Pharmacology Flashcards
What is the cascade of events when using GA ?
Describe the major organ responses of β1 and β2 agonists
- What Class of Drug induces Vomiting?
- Give an example of these
- What Class of drug would stop vomiting? What must you do before administration?
- Give an example of these
- Emetics
- Apomorphine (dopamine agonist) tablet mixed with water and then give IV or SC. or tab in the conjunctival sac. NOT FOR USE IN CATS
- Xylazine (Alpha-2 agonist at the CTZ) For CATS
- Anti-Emetics - Rule out GIT obstruction
- Metoclopramide (Maxolon) 1. anti-emetic effect (central action) 2. weak upper GI prokinetic effect (peripheral action) IV, IM, PO. Short DOA >6hrs
- Prochlorperazine (Stemetil) Blocks the CTZ via antidopaminergic and antihistaminergic effects
- Ondansetron (Zofran) Blocks Serotonin (5-HT3)
- Maropitant (Cerenia) Highly efficacious neurokinin-1 blocker. Stings! Use cold!
Define and explain the process of protein binding ?
Vd is affected by protein binding.
Drug molecules can bind to plasma proteins (albumin) = bound drugs.
Only free drugs can leave the blood
Protein binding is ; reversible & dynamic
with bound and unbound drugs is equilibrium.
Whatdo we need to check before using Prednislone eyedrops?
Must check for the presence of a corneal ulcer. DO NOT USE, can cause ulcer to get worse and eye rupture.
Provide examples of drugs which may inhibit or induce HME’s ? Hepatic metabolising enzymes
- Induced by anti-convulsants
- Inhibited by ketoconazole (anti-fungal) , can inhibit an expensive drug (cyclosporin) that is used in itchy skin - reducing the cost by using less of the more expensive drug.
- NSAID’s MOA will reduce inflammation by inhibiting cyclo-oxygenase (COX). Which COX would we prefer to select for?
- Name some NSAID’s that Select (Inhibit) for this COX.
- What is a NSAID with no selectivity
- COX-2
- Cox 2 Selective
- Firocoxib - Horses, Dogs, Cats
- Carprofen - Not as Selective for Horses
- Meloxicam
- Ketoprofen
What is the clinical uses of Tropicamide
- What is a MIC?
- What is MBC
- What if MBC>>>MIC?
- What if MBC ~ MIC?
Minimun inhibitory concentration
= the lowest concentration that prevents visible growth after 24hours incubation
Calculated quantitatively by serial dilution techniques
A MIC is a unique number that refers to a specific concentration of an antibiotic that will inhibit the growth of a particular bacterium. This means that there is a MIC for every combination of antibiotic-bacterium
- Minimum Bactericidal concentration = The lowest concentration where 99.9% of a culture is killed after 24hrs incubation.
- If MBC >>> MIC = Bacteristatic (microorganism arrestor)
- If MBC ~ mic = Bactericidal (microorganism killer)
Corticosteroids
What is a :-
- Glucocorticoids
- Mineralocorticoids
- Glucocorticoid - specifically relating to the corticosteroids predominatly produced by the Zona fasciculata “zone” of the adrenal cortex eg cortisol
- Mineralocorticoid - specifically relating to the corticosteroids predominantly produced by the Zona glomerulosa “zone” of the adrenal cortex eg. aldosterone
How does the vaopur concentration affect anaesthesia ?
Why does this occur ?
The more lipid soluble the vaopur the slower the
* anaesthetic induction
* rate of change of depth
* rate of recovery
Why - because the more molecules need to solubilise in the blood for equilibrium to establish or re-establish itself.
Explain the difference between the pattern of drug distrubution and the volume of distribution?
The propensity that a drug has for leaving the blood and entering thte tissues is calculated by the pharmacokinetic term volume of distribution (Vd).
Vd does not inform on the pattern of distrubtion ( lots of drugs in the brain) just the propensity of the drug to leave the blood.
List the sympathetic adrenoceptor agonist drugs and their uses.
- Adrenaline - Anaphylaxis, added to improve other drugs efficacy, cardiac arrest
- Noradrenaline - Similar to Adr but less Beta2 effects
- Salbutamol, Salmeteral - Beta2 agonists for rapid relief of bronchiolar constriction
- Clenbuterol - Beta2 Agonist primary affect the respiratory system but can cause uterine relaxation. This is used to facilitate calvings.
- Phenylpropanolamine - Alpha1 - Constriction of urethral smooth muscle retaining urine therefore used for urinary incontinence
- Xylazine - ALpha2 agonist - sedative
- Yohimbine - Alpha2 antagonist - Reverse sedative effects of Xylazine
- Phenoxybenzamine - Aplha1 antagonist - Relaxing the smooth muscle of the uretheral sphincter - helps clear urinary blockages
- Propranolol, Atenolol - Beta antagonist - Beta Blockers
Describe the factors and identify the rate limiting factors that affect drug absorption?
Disintegration
Dissolution
Absorption
Drug solubility
Surface area
First past metabolism ; exception of oral mucosa & rectum, all absorption from the ailmentary canal , goes directly into the portal vein an so drugs will be exposed to the metabolising enzymes in the liver prior to reaching the systemic circulation.
Vascularity / disease process; decreased blood supply to the site of admin will decrease absorption, decreased GIT motility , delayed gastric emptying leading to reduced exposure time to the small intestine.
Bupviacaine (LA) is beneficial for what applications ?
Why is this the case ? & when is it no appropriate to use ?
- Good for epidurals
- Long acting due to strong affinity with the sodium channels ,slow associatation and disassociation means its long lasting, but also slow to be effective
- when rapid desensitisation is required, due to the slow onset of action it takes a long time to become effective
Explain what ADT or EOD is?
What must you do when a patient is longer term steroids? and why?
Alternate Day Therapy
A method for achieving the lowest possible dose that is still therapeutic, eg Treating a patient with prenisolone for its atopy.
Cephalexin
Beta Lactam
1st Generation Cephalosporin
- Predominantly Gram +ve
- Well suited for Staph pyoderm
Define loading dose and maintenance dose rate ?
Loading dose - amount of drug given intially to obtain the desired plasma concentration asap, expressed in mg / kg.
Maintenance dose rate; rate at which drug needs to be administered to maintain a desireg plasma concentration , expressed in mg/kg/min.
Define the pharmacokinetic parameter of elimination half life T 1/2 .
Is defined as the time taken for the blood/plasma drug concentration to fall by 1/2 (50%).
The pharmacokinetic parameters that determine half - life , are Vd and clearance.
Tetracyclines
- What is the Spectrum of Activity for tetracyclines?
- List the specific diseases where these antibiotics are indicated.
- List the limitations, side-effects
- List teh Tetracyclines
Tetracyclines
- Broad Spectrum bacteriostatic - Gram +ves, Gram -ves (not Pseudomonas), Anaerobes (variable)
- Gold Standard against Chlamydia and good agains Mycoplasma and Rickettsia
- Common side effect is GIT upset with given orally. Some nephrotoxicity,
- Oxytetracycline, Doxycycline (upper respiratory tract small animals)
Name a phosphodiesterase inhibitor
Mode of Action
Contraindications
Pimobendan
Generalised vasodilation including pulmonary, artery less afterload.
Weak Vasodilator
Can I use Corticosteroids as an antimicriobial?
NO
Why are Second generation H1 antagonists (eg Cetirizine) often advitised as “non drowsy?
Histamine contributes to arousal (wakefulness) in the brain and therefore the antagonism of histamine can cause drowsiness. Because the 2nd generation H1 antihistamines do not cross the blood brain barrier significantly (unlike 1st Generation) this side effect reduced and these drugs can therefore be sold as being non drowsy
- What do Macrocylic Lactones kill
- What is their MOA
- Toxicity?
- Name some?
- Broad spectrum - nematondes and arthropods (not trematodes or cestodes).
- Equine -endo and ecto-parasites as oral
- Cattle endo amd ecto-parasites as topical pour-ons
- Sheep endoparasites as oral drenches
- Small animal Heartworm prevention and mite management
- MOA - agonist at glutamate R & GABA-Gated chloride ion channels
- Toxicity, Safe except in Collie breeds who MDR1 gene
- Ivermectin (heartguard plus), Moxidectin (Proheart), Selamectin, Milbemycin
What is the equipment needed for an IV or inhalant GA ?
What control and speed do you have for IV and inhalants for induction and maintenance ?
IV- minimal equip ; suitable for fieldwork, IM for wild animals.
Inhalant - substantial & costly, 02 supply, vaporiser, anaesthetic circuit.
Induction IV - easy, quick & smooth, Bolus doses can be dangerous. Maint -difficult to make even if using additional boluses doses. finer control if using IV CRI.
Induction Inhalant - difficult, slow , usually struggle but maintenance has fine control.
- What is the main side effect of NSAID use?
- What can we try and do to alleviate these side effects?
- What are the other NSAID Side Effects?
- What over the counter NSAID may kill a cat?
- Mostly related to inadvertent inhibition of Cox1 NSAIDS potentially cause Erosion, ulceration and haemorrhage of the GI tract.
- Use of anti-ulcer mediations
- Histamine type-2 blockers
- Proton-Pump inhibitors
- PGE1 analogues
- Barrier medications
- Effects - Related to the inadvertant inhibition of COX-1
- Altered Platelet Function
- irreversibly reduces platelet thromboxane (TXA2) and temporarily decrease endothelial PGI2 –> a net decrease in platelet aggregation used therapeutically as an antithrombic
- Kidney
- Potential for
- Water retention –> Hypertension
- Decreased renal blood flow leading to interstital papillary necrosis and nephritis
- Patients with heart disease are at greater risk of kidney related NSAID complications
- Potential for
- Altered Platelet Function
- 1/2 a 500mg paracetamol
Explain the difference between Efficacy and Potency
Efficacy - maximum effect that a drug can produce regardless of dose. Potency - amount of a drug that is needed to produce a given effect
Cefovecin (Convenia)
Beta Lactam
Very high protein binding (>99%) and decreases clearance rates in dogs and cats prolongs DOA to 2 weeks (will be more efficacious if given q7d)
Skin, Urinary and dental conditions
Difficult to pill animals and where compliance will be an issue, costs about the same as the equivalent oral course. But Beware of the colour change.
Drugs are scheduled depending on what 2 factors?
- The risk of harm to people when used appropriately and inappropriately
- The risk of addiction to people eg Heroin
What does a Insect Growth Regulator (IGR) do
- What is the downside?
- Name some
- IGR
- Insect Growth Hormone antagonists (they dont grow up, - eg Methoprene (the Plus in frontline)
- Inhibit the chitin synthesis pathways –> cannot develop, needed for exoskeleton and eggs
- Not an adulticidal, so must give one if adults are present
- Fipronnil, Imidacloprid, Spinosad, Indoxacarb (Activyl)
Beta-Lactams
- What is the MOA for Beta Lactams
- Define the Sub-Groups
Beta Lactams
- Penicillin tranverses Gram +ve cell wall and reaches cell membrane, Binds to Penicillin Binding Protien (PBP), Disrupts Cell wall synthesis, Bacteria lyse due ot impaired osmotic regulation. BetaLactams can only kill bacteria during thei replication phase. It is a Time Dependent Bactercidal
- SubGroups
- Penicillins,
- Cephalosporins,
- Carbapenems
Beta Lactams
Of the Carbapenem Sub Group what is the Spectrum of Action
- One of our Reserve Drug Classes
- extreamly efficacious
- Gram +ve and -ve aerobes and anaerobes
- highly resistant to beta-lactamases
- not effective agains vancomycin-resistant Enterococci (VRE) or Methicillin-Resistant Staphylococcus aureus (MSRA)
- Often used for severly ill immunocompromised people
- Imipenem, Meropenem
- What is a Prokinetics? And when are they used?
- What do you need to beware of when using?
- Name some
- Stimulating GIT motility, GIT motility often decreased after surgery
- Can make GIT obstructions worse
- Metoclopramine
- Cisapride Dose-Dependent increase in motility from Stomach –> LI
What Gram +ve Obligate Anaerobe is found in ruminants
Clostridum
Understand when a loading dose should be administered.
To quickly enter the therapuetic window of desired drug plasma concentration.
to “fill up “ the Vd. when it is necessary to achieve a high plasma concentration quickly
What are the central CNS effects of histamine?
- Maintains wakefulness
- emesis
- Pharmacokinetic variation
- within the H1 antagonists, lipophilicity can effect the ability to cross the BBB and cause drowsiness
Name an α2 antagonist and its Clinical Uses
Yohimbine
Used to reverse the sedative effects of xylazine
What is the purpose of an excipient?
Excipient is an inactive substance used to carry an active substance. It may make the drug work better or make the drug easier to work with.
Understand the factors of how loading doses are administered?
- Bolus
- Route
Without a LD, 3-5 half lives are required to reach a steady blood concentration.
With a LD , steady blood concentration is achieved straight away.
Name some of the local anaesthetic ?
What is the mode of action for LA?
- Lignocaine, Mepivacaine, Bupivacaine, Proxymetacine.
- Blocking conduction of nerve action potentials & binds to receptor site on neurons NA channel -sodium channel closes - no nerve conductions
What is a corticosteroid?
- Physiology - The steroids that are produced by the adrenal cortex eg cortisol, aldersterone
- Pharmacology - Symthetic steroids with corticosteroid like effect eg prednisolone, dexamethasone, methylprednisolone
What are Schedule 5 drugs?
Give some examples
Must have the word CAUTION on the lable, very low risk unlikely to cause harm.
- Glyphosate (roundup)
- Methiocarb (Baysol Snail Pellets)
- Petrol
- Ethylene glyco (Radiator Coolant)
- Warfarin (RatSack)
Name the Various Drug Administration Routes and list the advantages and disadvantages to each
There are 2 main routes of administration, Oral (PO = per oral or Per OS) and Parenteral (given by injection).
Oral ;drug absorption unreliable and slow through gi tract. safest, economical & convenient route.
Parenteral abreviations -; Most rapid route , high concentrations quickly in systemic circulation. injection injuries, celluitis, pain.
IV - Intravenous; immediate pharmalogical response direct into bloodstream
IM - Intramuscular; greater response than SC due to greater tissue blood flow
SC, SQ - Subcutaneous ; slow rate of absorption , sustained effect.
Intrathercal ; injected directed into the spinal subarachnoid space, bypasses blood brain barrier.
Epidural; injected into spinal canal on or outside the dura mater
Intraosseous; delivered into bone marrow
Intra- articular ; delivered into synovial cavity of a joint
Intraperitoneal; admin into peritoneal cavity
Intrapleural; admin into the pleura
What are the legal authorities who regulate drugs
WA Health Dept
Dept of Agriculture
Veterinary Surgeons Board
Of teh 3 Main Antibacterial targes which are Time depenent, Dose Dependent bactercidals or Bacteristatic?
Explain Placebo Controlled - (negative controlled)
A term used to describe a method of research in which an inactive substance (a placebo) is given to one group of participants, while the treatment (usually a drug or vaccine) being tested is given to another group
Which GA are considered barbituates ?
What is the mode of action for barbituates ?
What other applications suit this GA ?
- Thiopentone & pentobarbitone
- Barbituates decrease the CNS excitability via GABA agonism.
- injectable GA, anticonvulsant, humane euthanasia.
List the uses of Adrenaline and what adrenergic receptors it increases or decreases activity of.
What is the sequence of events that translate an idea into a registered and scheduled drug?
- Drug Development - Very expensive, long winded process undertaken by the drug company
- Drug Testing - Huge financial investment to get the drug to the market, testing is done under the supervision of the body who will register the drug.
- Registration - Australian Pesticides and Veterinary Medicines Authority (APVMA) registration legalises supply, sale and use of veterinary chemical. Therapeutic Goods Administration (TGA) registers the drugs for people often utilising independent scientific advice.
- Scheduling - TGA schedule all “poisons” via Standard for the Uniform Scheduling of Medicines and Poisons.
Of the following Drugs which will agonise which adrenergic receptors?
- Adrenaline (Adr)
- Noradrenaline (NAdr)
- Salbutamol (=Albuterol), Salmeterol, Clenbuterol
- Phenylpropanolamine
- Xylazine
In terms of Inhalant GA , what does MAC stand for?
What is MAC ? and how does this affect the vaopur setting.
Minimum Alveolar Concentration
Which is the partial pressure (concentration) if anaesthetic vapour required to anaesthetise
EG an anaesthetic vapour with a high MAC requires a lot of the vapour to be inhaled to achieve anaesthesia and so the vapour setting will be higher.
Procaine Penicillin
Beta Lactam
Large Animal Practices use this alot
Excellent anaerobic coverage (G+ and G-)
DOES NOT work against Beta lactamase producing bacteria
IM, SC NEVER IV
GA barbitaute Thiopentone is an ultra short acting anaesthetic and has a ___________ anaesthetic effect ?
How does this affect its useage ?
Other considerations ?
Thiopentone is a cumulative anaesthetic.
the culmative effect is most pronounced in lean dogs because there is less fat for the drug to redistribute to , leads to very long recoveries from post op sedation
Avoid thiopentone use in sighthounds, and it needs to be in a highly alkaline (ph11) solution to maintain solubility , dont use in liver failure or for caesareans.
List the things that the Sympathetic chain of the Autonomic Nervous System controls
Fight or Flight
What are Corticosteriod side effects?
- All the NSAID side effect (COX inhibition)
- GIT Ulceration
- Degrease PGE and Decrease PGI2
- additional action here is that is unclear decrease mucosal blood flow
- Kidney failure, hypertension
- GIT Ulceration
- Metabolic
- iatrogenic hyperadrenocorticism during therapy
- Suppression of the hypothalmic-Pituitary-Adrenal axis (HPA axis)
- Sudden cessation of corticosteroids leads to hypoadrenocortical crisis
- Immune System
- Immunosuppression
- more prone to infections and those infections will be more severe.
- Immunosuppression
List the uses of Noradrenaline and what adrenergic receptors it increases or decreases activity of.
Similar to Adr but has considerably less β2
effects
What are the Parasympatholitic drugs and thir clinical uses
Fluroquinolones
- What is the Mode of Action.
- Is there resistance and where should we not use them?
Flouroquinolones
- MOA = Inhibits DNA gyrase action –> Cell Death as cannot cut, untangle and rejoin DNA
- Big probelms once widespread resistance emerges, DO NOT use in Australia for food producing animals.
- REnal degeneration in Cats if label dose exceeded (5mg/kg), Cartlage Deformities (Chelates magnesium) avoid in growing animals
What are Schedule 10 drugs?
Give some examples
Substance of such danger to health as to warrant prohibition of sale, supply and use
Illegal importation
Substances that are prohibited for the purpose listed in each poison.
- Very strong alkali for domestic uses eg pH>11.5 (food additives) or Ph>12.5 (dishwashing additives)
- Ethylene glycol at > 0.25% in toothpaste or mouthwash
- formaldehyde at >0.1% in oral hygine products
- Paints with >0.1% lead
Briefly crtitique the manufactruere claim that their insect growth regulator registered for use against sheep lice is a “rapig knockdown lousicide” ?
Insect grwoth regulators by inhibitinh insect growth hormone and chitin synthesis they are not adulticides. Because they do not directly kill the lice, it is misleading to refer to them as lousicides.
Another LA topical use lignocaine with phenylephrine is more commonly used for ?
Mode of action ?
Other uses ?
topical LA to spray onto larynx of a cat prior to intubation,
Desensitises (not paralysis) & prevents potentially fatal laryngospasm in the cat
Can also be used for removing nasal foreign bodies & nose bleeds.
After Staining Bacteria what colour do Gram Positive bacteria stain?
What colour do Gram negative bacteria stain?
Purple = Gram Positive
Red = Gram Negative
In inhalant GA high lipid solubility gives you ?
A slow and low repsonse.
List the Neurotransmitters and receptors for the sympathetic, parasympathetic, somatic and neuroendocrine systems
Discuss with specific examples, the range of sequale for drug metabolism ?
- Excretion of water soluble metabolite
- Conversion of pro-drugs, through the formation of active metabolites (ie tramadol & prednisone)
H1 antihistamine toxicity?
- CNS
- sedation (drowsiness)
- But at high doses of after rapid IV administration, seizures or CNS excitement
- DO NOT GIVE H1 antihistamines intravenously
- Some antimuscarinic effects (dry as a bone, mad as ahatter, red as a beet)
- dry mouth, mydriasis, tachycardia
Define the term pharmacokinetic parameter clearance (CL).
Clearance describes the ability of an individual organ or the body to eliminate a drug.
List 3 major types of Diuretics
Relate site of action
Loop - Frusemide - Ascending Loop of Henley
Potassium Sparing (Spironolactone) - Collecting ducts
Osmotic (mannitol) -Moves fluid from tissues into plasma
What two controls should a drug study consist of? Describe why these are important.
1) Positive Control, Negative/Placebo Control. 2) In a drug study, a positive control is a compound that is widely accepted to have efficacy for a desired effect. A negative control should not have any effect, so any effect seen should be a representation of the error inherent to the study. By testing a drug against both of these controls, its efficacy AND proven inefficacy. These same controls can be used to measure a compound’s safety
Name some injectable GA ?
Thiopentone , pentobarbitone, propofol, alfaxalone,
ketamine, teletamine-zolazepam.
List the effects of Sympathetic discharge (aganosim)
What is a Placebo?
A Placebo is a tablet, injection etc that does not contain the active ingredient. It should be identical in its taste, appearance etc except that it has no effect (therapeutic or adverse.
What is the mode of action of a Glucocorticoid?
It inhibits Phospholipase A2 therefor decreasing Arachidonic Acid which suppresses COX (1 & 2) and LOX synthesis. Therefore decreasing prostaglandins and leukotrienes
Describe what is meant by Drug Absorption?
Getting the drug from site of administration into the blood (systemic circulation). No absorption phase for IV injections.
Rate and extent the drug gets into the blood is calcuated by the pharmacokinetic term - bioavailability
What are Schedule 6 drugs?
Give some examples
Poison - Moderate potential for harm. Distinctive packaging with strong warnings and safety instructions
- Arsenic (Ant Bait)
- Formaldehyde
- Selenium
- Brodifacoum
Phenylpropanolamine can be used for urinary
incontinence. Why must we be careful of its use
in hypertensive patients? (1 mark)
This drug is an alpha-1 agonist and will therefore
have a vasoconstrictive effect on the systemic
blood supply (except muscles). The use of this
drug would therefore be expected to exacerbate
the hypertension in the hypertensive patient.
Name some Fluoroquinolones
- Enrofloxacin
- Ciprofloxacin
- MarboFloxacin
What is Drug Compounding
It is the manipulation of a drug to form a
medication that is prepared by a veterinarian or
pharmacist on instruction (prescription) from an
authorised person e.g. doctor, dentist or
veterinary surgeon, to meet the specific medical
needs of an individual patient
Metronidazole
- MOA?
- Bactercidal or Bacterstatic?
- Spectrum of Action
Metronidozole
- Unknown MOA
- Bactercidal
- Excellent Anaerobic and anti-protozoal efficacy
- Kills Clostridium difficile (The bad gut anaerobe that prolifereates after you accidently wipe out the normal gut flora.
- What happens in anaphylaxis.
- What is used in the treatment of anaphylaxis and why?
- Why would we not use H1 antihistamine for anaphylaxis
- Can you use a H1 antihistamine on a puppy with a puffy face?
IgE binds to mast cells and cause (1) massive degranulation to release large quantities of histamine and (2) the release of other mediators
- respiratory smooth muscle contration –> bronchiolar constriction
- Arteriolar vasodilation –> Hypotension (species dependent)
- Adrenaline is used in the treatment of anaphylaxis because its ability to rapidly reverse hypotension and bronchiolar constriction is unmatched
- May work but you may be dead before the drug kicks in. May not work as other mediators are involved in anaphylaxis (cytokines, eicosanoids)
- Yes a hypersensitivity reaction to a vaccine, bee sting etc can be symptomatically treated with a H1 antihistamine, usually given with a glucocorticoid
Staphylococcus, Streptococcus and Enteroccus are all what kind of bacteria?
Gram +ve Facultative Anaerobe (Uses ATP when in presence of Oxygen and Fermation when not)
Propofol is a GA agent, what is the mode of action ?
Why are the benefits of using it for a GA?
Given as an IV or other ?
What is the general colour ?
Other uses ?
GABA Agonist with CVS depression, non cumulative drug.
rapidly taken up by the brain then rapidly redistributed and extensively metabolised which accounts for a rapid & smooth induction anaesthetic along with a smooth recovery for anaesthesia.
IV -extravascular absorption is poor
White
goood use in caesareans as its rapidly eliminated by newborns & anticonvulsant ; MPEC will condiser CRI propofol if diazepam( +/- phenobarbiatone) is unable to control seizures.
Explain Randomisation
A study in which people are allocated at random (by chance alone) to receive one of several clinical interventions
Beta Lactams
- In the Subgroup Penicillins give us the Spectrum of activity
- Natural Penicillins
- Narrow Spectrum
- Predominatly Gram +ves and Anaerobes
- Staphylococcus (only non penicillinase producing) Streptococcus, Obligate anaerobes (eg Fusobacterium)
- Penicillin G (Procaine and benzathine salts), Benzylpenicillin
- Aminopenicillins
- Broader Spectrum
- Same as Natural Penicillins plus some Gram -ves eg. E.Coli and Proteus
- Amoxycillin, Ampicillin
- Others
- Beta-Lactamase stable penicillins eg methicillin (MRSA), cloxacillin
- Extended spectrum eg. ticarcillin, piperacillin
- What is the MOA for Pyrethrins & Pyrethroids
- Give some examples
Affects the sodium channels capacity to depolarise –> death of parasite
- Anything endint with thrin
allethrin, permethrin
What are our front line corticosteroids that we use in Veterinary practice, What are their Duration of Action
- Prednisolone, 24-36hrs (IV, Tablet, Oral Liquid, Granules [For horses/Chronic Skin conditions])
- Dexamethasone Overused and Misused DOA 72hrs, Onlable Pigs, Cattle, Sheep, Horses, Cats and Dogs
- Hydrocortisone acetate - Old topical cream that gets licked off
- Hydrocortisone aceponate “Cortavance” (Brilliant idea absorbed through skin)
HISTAMINE
What does a H1 receptor do
What does a H2 receptor do
- H1 receptor
- Veno- and arterio dilation, increased vascular permeability –> erythema & oedema during inflammation
- Contraction of GIT and respiratory smooth muscle –> anaphylaxis
- Therefoe, the H1 -antagonists are used for histamine-mediated inflammatory processes e.g pollen allergies
- H2 receptor
- Mediates gastric acid secretion using non-mast cell poool
- therefore, the H2-antagonists are used for histamine-mediated gastric ulceration
Why is the idea of a single dose of each antibiotic (eg what the dose rate of clav?) an overly simplistic one?
Different species (and even different strains and different isolates of the same species) of bacteria will have different susceptibilities to the same antibiotic. so choosing one dose for each antibiotic, and expecting it to applyy to all bacteria is naive, ignorant, cretenous and moronic
What are the legal authorities that oversea the testing, registration, scheduling and regulation of various poisons
APVMA for Veterinary Chemicals
TGA for Drugs for people
Name a topical antifungal sutible for dermatophytosis in a dog
Miconazole, clotrimazole
Decribe the fate of the drug
Define and explain the concept of apparent volume of distribution ?
V is therefore an apparent volume of distribution , it is mathematically determined and so is not bound by rules of physiology.
How do we find out is a pathogen is sensitive or resistant to the antibiotics we have available?
- Grow the Bacteria
- Add a disc of antibiotic and observe that happens
Amoxycillin - Clavulanic Acid
HotSpots - Staphylococcus pseudintermedius
Beta Lactam
Most common antibiotic in small animal practice
- Predominantly Gram +ve
- Excelent Anaerobic (G+ & G-) coverage
- Works against many Beta-lactamase producing bacteria
- IM, SC NEVER IV
- SID
What NSAIDs do we use for Equine patients
- Phenylbutazone “Bute”
- No Cox1/COX2 selectivity
- Excellent analgesic for lame horses
- Meloxicam
- Large Animal increased concentration
- uncommonly used
- fewer side effects than Bute
- Flunixin
- Very Common
- Excellent analgesic for colic horses
What are Schedule 1 drugs?
Give some examples
This is not currently in use.
No examples
- When using a Laxative what do you need to be careful of
- When are laxitives used in clinics
- Name a Emollient Laxative
- What is a Cathartic
- Name some Osmotic cathartics
- Beware of dehydration
- Horse sand colic, Old dehydrated cat.
- Paraffin Oil, Docusate Sodium (Coloxyl)
- (purgatives = more fluidy evacuation
- Magnesium Sulphate (Epsom Salts)
- When using ketamine , what cannot be used as an indication of effectiveness ?
- What ketamine variations are good for sheep and horses ?
- Other effects of ketamine ?
- Human use has it scheduled as an S?
- Many reflexes are still present (other GA dull the reflexes and can then be used to guide the depth of anaesthesia)
- Sheep ( xylazine-ketamine) & Horses (xylazine-diazepam-ketamine)
- No CVS depression, increase in sympathetic drive.Dont use on own-stormy recovery
- S8 due to human abuse, must be locked away and recorded.
What could administration of corticosteroids cause in a horse?
Can I give corticosteroids with NSAIDS to Horse? eg Lame horse with an allergy
To all other Species of Animal?
Laminitis
Yes - Horses seem to be highly resilient to the adverse effects of concurrent use of CSts and NSAIDs
No - Synergistic side effects (1+1=3)
List the effects of excessive ACh discharge
What is the difference between local anaesthetics ?
General mode of action ?
- no qualitative differences so all will numb an area equally. variations in speed of onset of action and duration of action are related to the affinity for the receptor.
- the nociceptive fibres have less myelin and are closer to the surface of nerve bundles allowing a better chance a LA will work on them
Using the graph, classify a drug as being
agonist
antagonist
partial agonist
What questions would you ask a prospective compounding pharmacy you are intending to use the services of?
• Does the pharmacist have experience and training in complex compounding of
veterinary products and comply with the Pharmacy Board of Australia Compounding
Guidelines and published pharmacy practice standards in compounding?
• Are (and what) quality assurance programs are in place?
• Do sterile compounding facilities
comply with the Australian Standards
for clean rooms and are there sterility
testing programs in place?
• What are the Standard Operating
Procedures (SOPs) in case of a recall,
compliant or adverse reaction?
• Does the pharmacist have or have
access to the appropriate texts and
reference books for animal dosages and
side effects?
How is Food Withholding Periods determined?
How long till the drug residue drops below the Maximum residue limit (MRL)
List the effects of parasympathetic discharge
REST
• CVS
– decreased heart rate
– mild decrease in atrial
myocardial contractile
strength
(weaker effect on ventricles)
• Respiratory system
– bronchiolar constriction
ANd Digest
• GIT
– profuse watery salivation
– increased GIT motility
– increased gastric acid secretions
– sphincters open – not anal
– defaecation
• Miscellaneous
– micturition via fundic contraction and
trigone/sphincter relaxation
– pupils contract (miosis)
– lacrimation
What are the isoxazolines?
MOA
Name some
Chewable dog tablets for ticks and fleas
End with Laner
Fluralaner (Bravecto)
Afoxolaner (NexGard)
Suralaner (Simparica)
MOA = Neural Toxicity
Understand the advantages and disadvantages of compounded drugs.
- Advantages
- Can get what you want
• compounds that are no longer commercially
viable can be made available to the veterinary
market like cisapride (heart attacks in small % of
people)
• assuming not under patent
• assuming raw drug is available - Can get it how you want it
• exact amounts of drug (e.g. 12.5mg instead of 250mg) in
capsules, tablets and injections
– e.g. amlodipine – 1/8th of a small tablet
• Transdermals
– be VERY cautious
– can you measure the drug concentration or the effect of the
drug (e.g. feline hyperthryoidism)?
• flavoured with a wide range of palatants
• “polypills” e.g. 3 drugs in 1 pill - When you want it
• the efficacy and the safety of the products does not
need to be proved so things get done quickly - Sometimes cheaper
• registered products exist but you can use a cheaper
compounded version (a “mimic” drug)
– compounding pharmacist has access to wholesale
prices of drug from chemical supplier
– e.g. pimobendan, fluconazole
– makes the drug companies VERY upset
– illegal in US, not Australia
• OWNER CONSENT!
- Can get what you want
- Disadvantages
- Efficacy is unproven
– 80% of patients will get better despite what you do
– can you OBJECTIVELY measure the plasma concentration or an
effect of the drug?
• plasma concentrations following the administration of cyclosporine
• very difficult to assess the efficacy of analgesics (pain killers), antibiotics
and many other drug types - Safety is unproven
- quality control??
• drug company = good
manufacturing practice (GMP) =
VERY high standard
• compounding pharmacist = the
professional standards of the PSA - how long is the preparation
stable for (e.g. what is the
expiry date)??
• “intended for immediate usage”,
Pharmaceutical Society of Australia (PSA)
• for the expiry date, often an
arbitrary date of 28 days is applied
• an American compounded
preparation of doxycycline was
found only to be stable for 7 days,
despite the unsubstantiated claim
of 28 days
- Efficacy is unproven
What are the H1 Antihistamine drugs
- 1st Generation
- 2nd Generation
What do Immunomodulators do?
What are the 2 that we use?
- Chlorpherniramine (for allergies, to lower Corticsteroid doses used in atopy DO NOT GIVE IV)
- Cetirizine (Zyrtec) - Less lipophilic so cross the BBB less, so result in less drowsiness, primary used for allergies
Immunomodulators - Block Interleukin-31 which is involved in sending messages from the periphery to brain that is interpreted as itchiness. (injection of IL-31 elicts a pruritic response, dogs with atopy have higher blood concentrations of IL-31 than those that dont.
- Oclacitinib (Apoquel)
- Alternative to Glucocorticoid for atopic and allergic dog.
- tyrosine kinase inhibitor (Blocks interactions between IL-31 and the nervous system
- Lokivetmab (Cytopoint)
- Not yet approved by APVMA
- OOA = 8hours, DOA = 1 month
Beta Lactams
Of the Cephalosporin SubGroup What is thier spectrum of activity
- First Generation
- Spectrum similar to aminopenicillins but:
- Less anaerobic activity but better activity against Staphylococcus
- Cephalexin, Cefazolin
- Spectrum similar to aminopenicillins but:
- Second Generation
- Expanded Gram -ve activity
- Decreased Gram +ve activity
- Not commonly used in some intrammaries for bovine mastitis
- Third Generaion
- Further improved gram -ve activity but reduced gram +ve activity
- Ceftiofur, Cefyazidime, Cefovecin
What spectrum of activity would you exspect from a topical preparation of imidacloprif and moxidectin in a dog ?
Treatment of fleas, mites (including demodex) and intestingal nematodes. Also prevention of heartworm.
Name an α2 agonist and its Clinical Uses
Xylazine
used as a sedative
- What is the mode of action for a Barbiturates
- What are some that we use
- What would you not use Barbiturates for?
- Decrease CNS excitability via GABA Agonism.
- Propofol (White Liquid that goes in vein), Alfaxalone
- Dont use for Liver Failure or caesareans
What is the difference between a poineer (innovator), generic and compounded drug?
- Pioneer drugs the company has spent $millions creating the drug, testing the drug and satisfying stringent regulatory requirements of safety, efficacy and manufacturing. Because of this they have a patent period of 10 years meaning no other company can copy the drug and sell it within that period meaning the price can be what ever the drug company wants.
- Generic - company has spent 10s-100s of thousands of $ creating a copycat drug whose bioavailability has been proven to be within an acceptable range of the pioneer product (=bioequivalence). Payoff = ability to sell an expensive and/or high demand product at a cheaper price and therefore make some money by getting into a new market.
- Compound - Company has not spent a significant amount of money to create an unregistered preparation of a drug whose bioavailability (and therefore bioequivalence) is unproven and therefore the safety and efficacy of the product is unknown. Pay off = freedom to create novel preparations that meet the doctors/dentists/veterinarians needs
What drug could you use if your bitch had urinary incontinence?
How does this work?
Phenylpropanolamine
Describe the major organ responses of α1, α2 agonists
What is cumulative anaesthetic ?
- Dose 1 (give drug) anaesthesia occurs given the dose is high enough, then the anaesthetic wears off because lots of the drug has redistributed from the brain to the less perfused organs.
- Dose 2 given while the animal is sedated / during anaesthesia (ie before dose1 has cleared the body) leads to anaesthesia which then takes longer to wear off because distribution away from the brain is slowed down by the blood having lots of drugs in it .
What are the increased requirements for the safe use and dispensing of S8’s
- Must live in locked Safe
- Must keep a Register of Drugs of Addiction recording all incomings and outgoings, every dose is to be signed off by a Vet, Dr or dentist, Inventory to be done monthly, kept up to date and ready for unannounced spot audit by WA Health Dept
Explain the Spectrum of activity
How can administration frequency influence the efficacy of beta lactam antibiotics?
Beta Lactam antibiotics are time dependent bactericidals and for antibiotics of this class, efficacy is increased by maximising the lenght of time that the plasma concentration exceeds the MIC for the bacterium causing infection. This means by administrating beta lactams more frequently (eg TID compared to BID), efficacy is improved. Conversely administering the beta lactams less frequently decreases efficacy
What are some clinical Applications of Corticosteroids
MANY
- Replacement in adrenal insufficiency (Addisons = underactive adrenal cortex)
- Induction = initiating Birth
- Supraphysiologic to help with Ketosis
- Supraphysiologic to suppress
- Allergy - Atopy (=envrionmental skin allergies), insect bite hypersensitivity
- Inflammation - General Inflammation (bandaid solution)
- Immune Disease (eg autoimmune disorders)
- Veterinary Dermatology
- Ears
- Indctions
- Equine Airwaw Disease - Inhaland corticosteroidsAutoimmune Bleeding Disorders
- Shock (DO NOT USE) as exaserbates the reduction in perfusion of extremities
What are Schedule 8 drugs?
Give some examples
Controlled Drug
available for use but manufacturing, supply, distribution, possession and use restrictions apply. Prone to abuse and misuse. No public advertising.
Sources - Pharmicist, veterinarian. Can only be prescribed by vets, Doctors, Dentists
- Codeine (Highest Doses)
- Ketamine
- Methadone
- Morphine
- Alprazolam (xanax)
Local anaesthetic lignocaine is very commonly used for ? & any contraindictations/ side effects ?
For Cow caesareans & stitch ups
Stingy due to the aciditic to maintain its solubility
Summerise Pharmacokinetics (ADME)
What NSAIDS would we use for productions Animals (Cattle and Pigs)
What NSAID can we use on Sheep?
- Flunixin
- Old, Cheap Established WHP’s
- Tolfenamic Acid
- Expensive but fewer side effects than Flunixin
- Established WHP’s
- Meloxicam
- Large Animal Prep with increased Concentration.
- Fewer side effects
- Phenylbutazone
- Good analgesic for lameness pain
- NO ESTABLISHED WHP’s in production animals due to decreased and unpredictable drug clearance.
- Buccalgesic / Meloxicam
LA Proxymetacaine is commonly used for ?
Excellent topical LA for ocular examination
The 3 main antibacterial Targets
- Inhibitors of Cell Wall Synthesis
- Inhibitors of DNA Synthesis and integrity
- INhibitors of Transcription and Translation
- Beta Lactams (Penicillins, Cephalosporins)
- Sulphonamides, Flouoroquinolones
- Aminoglycosides, Tetracyclines, Macolides
What are Schedule 9 drugs?
Give some examples
Prohibited Substance
Illegal substance. only available for scientific/medical purposes and only once permission granted.
Sources - street dealer (import/exporter), some chemical suppliers
- coca leaf (cocaine)
- Cannabis
- Etorphine (Elephant Juice)
- Herion
What is a general anaesthetic ?
What are the 2 main types of GA ?
What does titrate mean in regards to GA ?
- A generalised , reversible depression of the CNS , leading to a lack of perception from ALL senses.
- Injectable & inhalant
- Give drug until desired effect is achieved .
Determine the factors that allow the maintenance dose rate to be converted into a practical dosing interval.
- Drug clearance - know the maintenance dose rate required (3mg/kg/hr).
Real World
- How quickly the plasma drug concentration decreases (half life)
- Therapuetic window
- Compliance
Aminioglycosides
- What is their Spectrum of Action? Pathogen and Bacteria
- What is thier mode of action?
- Are aminoglycosides Dose Depentent of Time Dependent?
- What is their Post-Antibiotic Effect? (PAE)
- Name some Aminoglycoside Toxicity’s
Aminoglycosides
- Gram -ves but good against staphyloccus spp, Not anaerobes.
- Through cell membrane via oxygen-dependent transport system.
- MOA = influx into bacteria –> cause breakdown in protein synthesis –> Bactercidal effect
- Dose Dependent
- Long PAE - Bactericidal after plasma concnetration < MIC
- Ototoxicity, Nephrotoxicity
- Who can request Drug compounding?
- Who does the Compounding?
- Who may use the compounded drug?
- An authorised person e.g. doctor, dentist
or veterinary surgeon via prescription. - prepared by a veterinarian or pharmacist
- meet the specific medical needs of
an individual patient.
Describe what is meant by the term firstpass
metabolism (2 marks).
This is where a drug is metabolised before it
enters the systemic blood supply. This
reduces the bioavailability of the
administered drug. For example, the oral
bioavailability of morphine is reduced due to
pre-systemic hepatic metabolism
Describe Parasympatholytic toxicity
List the clinical uses of Clenbuterol and what adrenergic receptors it increases or decreases activity of.
Name some Anti-Diarrhoeals
Diarrhoea is a sympton not a disease
- Opiods (MOA - increased water retention and increased transit time) Loperamide (imodium), Diphernoxylate (Lomotil)
- Kaolin (Scourban) - Clay that non-specifically absorbs everything. Production animals >Horses>Small Animals
- Activated Charcoal
Sulphonamides
- What is the mode of action?
- Are the Bactercidial or Bacteriostatic?
- What is their spectrum of action
- What is their toxicity?
- What are some Sulphonamides
Sulponimides
- Inhibit the synthesis adn conversion of folate (which must be synthesised by bacteria)
- Bacteriostatic
- Broad Spectrum - Gram + & - and coccidia (protozoa)
- Toxicity
- Hypersensitivity esp Doberman Pinschers - Hepatic Necrosis
- Keratoconjuctivitis sicca (KCS = Dry eye)
- Sulfadiazine, Trimethoprim, Silver Sulphadiazine (Flamazine)
What are Schedule 7 drugs?
Give some examples
Dangerous Poison
High potential for causing harm specially regulated and only available to authorised users. Can only be purchased from specialised chemical suppliers
- Strychnine
- Fluoroacetate (1080)
Mepivacaine (LA) is commonly used by vets for ?
Benefit to the animal when using ?
Equine use for nerve blocks in lame horses
Less irritating then lignocaine
Name an antibiotic suitable for chlamydia in a bird
Doxycycline
Corticosteroids are used at various doses depending upon what we are trying to achieve, what are some examples of this?
- Prednisolone in a dog
- Anti-Pruritic (anity-allergy) = 0.5mg/kg/day
- Anti-inflammatory - 1mg/kg/day
- Immunosuppressive = 2mg/kg/day
- Double it for cats
Always try and use the lowest possible dose for your patient to minimise side effects
Explain the difference between on label and off lable use
Off-Lable use is using the drug for a different species, at a different dosage recommendation (dose, route, frequency and duration) and/or a different purpose.
The Safety and efficacy has not been proven for such off lable use.
Where are most drugs eliminated from ?
Kidneys
- removal of drug from the body is usually from the urine / kidney.
- can be accelerated by diuresis
- can be slowed by Kidney and Heart disease.
- elimination is quantified by drug clearance.
List the clinical uses of Salbutamol, Salmeterol and what adrenergic receptors it increases or decreases activity of.
Blue Inhalers
Name the Adrenergic Antagonists and in atable what subclasses do they effect
Macrolides
- Bactercidal or Bacterioistatic?
- Dose or Time dependent?
- Spectrum of action
- Mode of Action, Good for?
- Name some
Macrolides
- Bacteriostatic
- Time Dependent
- Gram +ves and select few Gram -ves (Pasteurella), Moderate to excellent anaerobic coverage
- Macrolides get trapped in acidic environments eg abscesses, necrotic tissue, lungs, maststis, metritis, Bovine Respiratory Disease (BRD)
- Tylosin (concentrates in milk), Tilmicosin (SC only - will stop heart if given IM, IV) not to be used in Dairy Cows, Tulathromycin (Respiratory disease and 12 week dosing interval) SC for cattle, IM for pigs.
What are the 6 Mechanisms of Antibiotic Resistance?
- Intrinsic resistance eg. aminoglycosides and anaerobes
- Via a decreased permeability to the drug in the cytoplasmic membrane eg. some beta lactams and many gram -ves
- Increased production of a drug-destroying enzyme eg. beta-lactamase
- The target enzyme/protein is replaced by one with less affinity for the drug eg. altered penicillin binding protein in MRSA
- Active extrusion of the drug via MDR P-glycoprotein pump eg. Pseudomonas spp.
- Biofilms provide a barrier to host’s immune system and many antibiotics. Biofilms occur at solid-liquid interfaces eg. Bladder wall, Joints, IV Catheters, ear canals
Explain Positive-Controlled
Is a compound that is widely accepted to have efficacy for a desired effect.
Name an α1 antagonist and the clinical uses
What NSAID’s would be used for a dog and why?
- Cox-2 selective NSAIDS - coxibs
- Firocoxib “Previcox”
- Dogs - Oral
- Robenacoxib “Onsior”
- Dogs and Cats - Impressive Feline palatability
- Mavacoxib “Trocoxil”
- Dogs
- Dosing regime: Dose on day 1, 2 weeks later then monthly for 5 months, then one month off. (But can use other NSAIDs during rest period.
- Dogs
- Firocoxib “Previcox”
What is the most important thing you need to do/get before prescribing this for your patient?
Make sure the owner or patient has provided
INFORMED consent
– beware of “the vet never told me that a registered
version of this drug already existed”
– beware of “whatever you say doc” ≠ informed
What are some Common and Sporadic glucocorticoid side effects seen in the Early and Late stages of use?
EARLY (Days-Weeks)
- Common
- Polyuria and Polydipsia (ADH inhibition)
- Mood Change
- Euphoria/Dysphoria
- Weight Change (PP=Polyphagia)
- Catabolic State
- Transient adrenal suppression
- HPA suppression
- Sporadic
- Peptic Ulcer
- Decreased Mucosal blood flow
- Peptic Ulcer
LATE (Months-Years)
- Common
- Central obesity
- Redistribution of fat
- pendoulous abdomen
- Hair Loss
- Prolonged adrenal suppression
- HPA Suppression
- Central obesity
- Sporadic
- Cataracts/Diabetes
- Sugar levels too high in blood. Sugar deposits in lens and renders it opaque
- Hypertension
- Cataracts/Diabetes
What are Schedule 2 drugs?
Give some examples
Pharmacy Medicine
Safe use may require advice from a pharmacist.
- Asprin (<= 325mg*, <=500mg*, <=625mg*)
- ibuprofen (<=200)
- Paracetamol (<=500mg*, <=1000mg*)
* depending on pack size
- What are the 2 phases of drug metabolism?
- What is the purpose of Drug metabolism?
- 2 Phases of drug metabolism are
- Phase I (the P450 enzymes)
- Phase II (usually through glocuronidation)
- The biotransformation of a lipophilic compound
into a more hydrophilic compound in order to
facilitate elimination.
The more hydrophilic metabolite can be
eliminated by the kidney more easily
Phase II Metabolism deficiencies - Feline : Slow with some of the (not all) glucuronidation pathways
What is Post-Antibiotic Effect (PAE)
Persistent suppression of bacterial growth after removal of the antimicrobial agent.
Theories
- Drug persistence
- Synthesising enzymes prior to replication/slow recovery to non-lethal damage
What are Schedule 0 drugs?
Give some examples
Uncontrolled Products,
Chemicals used in childrens chemistry sets, most cosmetics, mosquito control, matches.
What are Schedule 4 drugs?
Give some examples
Prescription only medicine (peo ple) or Prescription animal remedy (animals)
Use and Supply only by permitted persons, Can be dispensed by pharmacist through a prescription. NO PUBLIC ADVERTISING
Sources - Pharmacist, veterinarian. Can only be prescribed by vets, doctors, dentists
- Asprin (if with paracetamol)
- Codine (<=30mg)
- Paracetamol (Slow-Release or >=500mg* or >=1000mg*)
* depending on pack size
Explain Double Blinded
A double-blind study is one in which neither the participants nor the experimenters know who is receiving a particular treatment. This procedure is utilized to prevent bias in research results. Double-blind studies are particularly useful for preventing bias due to demand characteristics or the placebo effect.
What are the clinical uses of Atrophine
- Anaesthesia -
- • primarily acts on HR. No effect on vascular tone; minimal effects on myocardial contractility
• used for reversing intraoperative bradycardia
• still used in private practice as a preanaesthetic medication to attempt to
diminish the CVS depressant effects of some of the anaesthetics and sedatives. This is no longer recommended
- • primarily acts on HR. No effect on vascular tone; minimal effects on myocardial contractility
- Atrophine for methiocarb toxicity
- because atropine is an antimuscarinic it
can be used to treat the muscarinic side
effects of OP/methiocarb toxicity
– i.e. vomiting, diarrhoea, lacrimation,
salivation, bradycardia etc
– dose conservatively: too high a dose will stop the GIT and prolong the residence time of ingested toxins
• but because it’s not an antinicotinic the
nicotinic effects will remain unchecked
and other treatments are used for these
side effects – i.e. muscle tremors
• there are also central CNS excitation
signs to worry about e.g. seizures
- because atropine is an antimuscarinic it
- Opthalmology
- commonly used as a cycloplegic (ciliary muscle paralysis to relieve ciliary spasm)
– part of the pain of a corneal ulcer is from ciliary muscle spasm
• will cause mydriasis for 1-3d+!
– beware of subsequent retinal damage
• for the ophthalmological examination of the retina, a mydriatic is needed but atropine should not be used for this purpose because the effects last too long
• contraindicated for glaucoma
– a consequence of mydriasis is closure of the aqueous drainage channels -> intraocular pressure (IOP) will increase and glaucoma will become worse
- commonly used as a cycloplegic (ciliary muscle paralysis to relieve ciliary spasm)
Explain the difference between Statistically significant and clinically significant
Results are said to be “statistically significant” if the probability that the result is compatible with the null hypothesis is very small. … Clinical significance, or clinical importance: Is the difference between new and old therapy found in the study large enough for you to alter your practice?
What are Schedule 3 drugs?
Give some examples
Pharmacist only Medicine
requires advice from pharmacist. No prescription needed.
- ibuprofen (<=400mg)
- some paracetamol-ibuprofen combinations
Combination drugs are scheduled according to the highest scheduled active
Define Pharmacokinetics
The study of the movement of drugs within the body and encompassing absorption, distribution, metabolism and elimination =ADME WHAT THE BODY DOES WITH THE DRUG
Define Pharmacodynamics
The study of the pharmacological response to the drug WHAT THE DRUG DOES TO THE BODY
Alfaxalone is a GABA _________ ?
Does alfaxalone have a cumulative effect ?
Does it have an analgesia effect ?
Given IV or IM ?
Alfaxan-CD RTU means ?
Agonist. smooth induction of anaesthetic
No cumulative effects -& can be used to provide top ups .
some analgesia -but limited evidence
IV vastly better than IM , extrvasation stings but doesnt cause tissue sloughing
Alfaxalone cyclodextran ready to use.
- What is the TOxicity of Beta Lactams?
- Side effects of Beta Lactams?
- Very Safe, can be used in geriatrics, juveniles, pregnancy and during lactation
- Usually come about through dysbiosis
- Killing good bacteria, recolonisation by a monomorphic population, toxin, GIT signs
- Diarrhoea, vomiting most common
- small herbivores
- Accidental IV with some preperations
ALLERGIES
Seems to be only a human problem only.
Discuss how pharmacogenetics can affect drug efficacy and safety?
What are some reason why you would use a nerve block?
- Cow Caesarean - Inverted L-Block, Paravertebral never block
- Epidural - Calvings, Cruciate surgeries
- Dehorning
- Stitchups under Local
- Intravenous Regional Analgesia (IVRA) - Digit amputation MUST use a torniquet
- Peripheral Nerve Blocks - Blocking out entire regions of the leg
- Topical anaesthesia - third eye lid
- Regional Anaesthesia - Dental Blocks
Describe the role that ACh plays in the peripheral nervous system (sympathetic, parasympathetic and somatic) and describe the effects that ACh has on the major organs/systems
Acetylcholine will activate all :-
- Nicotinic and Muscarinic receptors in the Parasympathetic Pathway
- Nicotinic receptors at the ganglion of the sympathetic pathway
- Nicotinic receptors on the skeletal muscle of the somatic nervous system
Describe why extemely large burdens of ascarids should be treated in a cautious manner?
AScardis are large worms and incredibly high numbers can be found infesting a single animals intestine. If an anthelmintic is chosen that has high efficacy against the ascarid in question, mass ascarid die offs can cause verminous impactions in the gut .
List two antibiotics that would be suitable as an emprical selection for sepsis in a foal
A beta-lactamase resistant beta lactam and an aminoglycoside. Eg amoxycillin-clavulanic acid & Gentamicin.
This will provide broad spectrum Coverage with the ammoxycillin-clavulanic acid targeting the Gram +ve aerobes and Gram +ve and -ve anaerobes, while gentamicin will target the gram -ve aerobes
Bactericidal Antibiotics can be divided into 2 groups what are they?
- Time Dependent Killers - Duration of time (at any concentration beyone MIC) determines how many bugs are killed
- Dose Depentent Killers - The difference between the drug concentration and MIC determines how many bugs are killed eg. AUC:MIC, Cmax:MIC (=IQ)
Pentibarbitone primary use is ?
How is it used ?
What colour is the solution ?
Any other effects ?
Euthanasia solution
give an IV overdose quickly to euthanase the animal
high concentration preparations contain green dye
dont use in liver failure or caesareans.
Name an NSAID that is registered for use in a cat.
Meloxicam
- Explain the Mode of Action of NSAID’s
- What are the two isoforms?
- Inhibits Coclooxygenase 1 & 2 which reduces inflammation.
- Cox 1 (Constitutive) - Aways working to produce house keeping products with numerous protective roles. In blood vessels, Gastrointestinal mucosa and kidney PGE2 PGI2
- Cox 2 (Induced) - Induces after an insult (trauma etc) to produce the mediators of inflammation, pain and pyrexia
Inhalant GA are described as ?
What are the driving inputs of a gas anaesthesia ?
Name some inhalant GA formulations ?
- drugs that are given and largely remove using the lungs
- Oxygen, anasethetic gas which is an anaesthetic liquid converted into a gas by a vaporiser.
- Halothane, Isoflurane, Sevoflurane.
What does Parasympathomimetics mean?
List the Major Parasympathomimetics drugs and their clinical uses
- Parasympathomimetics = Muscarlinic Agonist
- Bethanecol
Compare the following four agonists to each other using the following criteria: Full v Partial agonist and realitve potency
- A = full agonist (assuming plateaus at maximum response), 2nd most potent
- B = partial agonist, most potent
- C = full agonist (assuming plateaus at maximum response), 3rd most potent
- D = full agonist (assuming plateaus at maximum response), least potent
List the things that the Parasympathetic chain of the Autonomic Nervous System controls
Rest and Digest
Aminoglycosides
Name some Aminoglycosides, what animals, Spectrum.
- Gentamicin, Horses, Broadening Spectrum (combine with Beta-Lactams), Banned in Food producing animals
- Amikacin, Less resistance and safer than Gentamicin, VERY EXPENSIVE
- Neomycin/Streptomycin - Went out with the ark
Graph the difference between Time dependent and Dose Dependent Bactericidals
Name an antibiotic suitable for pneumonia in a feedlot cow.
ANy one of : tylosin, timicosin, oxytetracycline, florfenicol, ceftiofur
Using your knowledge of the physiology of acid secretion in the stomach, discuss why the proton pump inhibitors are the strongest medicaitons for treatment of gasteric ulceration
There are various stimuli that all result in acid being secreted into the stomach eg. neurocrine (acetylocholine), pancrine (histamine) and endocrine (gastrin). Proton pump inhibitors are the most effective anti-ulcer medications because they will stop the release of acid into the stomach irrespective of the initiating cause. All other anti-ulcer medications are limited to more specific causes of acid secretion in the stomach
If we were treating Addisons Disease what groupd of corticosteroids would we use?
Addisons disease (= adrenal cortex insufficiency = hyperadrenocorticism) is more specifically a deficiency in Mineralocorticoid production more than it is a deficiency in glucocorticoid production. Therefore with replacement therapy we usually select a corticosteroid with preferential affinity to, and efficacy at, the mineralcorticoid receptor. eg flurocortisone
Each Corticosteroid has a unique “Spectrum” of activity
- Most are more efficacious at the glucocorticoid receptor
- Some are more effacious at the mineralcorticoid receptor
- Others are equal
Discuss how glucocorticoids can have both hyperadrenocorticism and hypoadrenocorticism as adverse side effects?
Exogenous glucocorticoids (ExGC) will mimic the effects of endogenous glucocorticoids (EnGC) and so if excessive amounts of ExGC are administrated, the effects will be indistinguishable from the adrenal gland disease wehre excessiver amounts of EnGC are produced hyperadrenocorticism.
ExGC will also act to negatively feedback on the release of Corticotropin-Releasing-Hormone (CRH) and Adrenocorticotropic hormone (ACTH) from the hypothalamus and the pituitary gland respectively. This results in a decrease in the production of EnGC. If the exogenous administration of GCs stops suddenly, the body will not have adequate amounts of GC for normal body functions. This disease is called Hypoadrenocorticism.
List an advantage that an inhalant offers over an injectable agent during induction of general anaesthesia?
Mask induction does not require the animal to be injected and considering most injectable general anaesthetics should be given intravenously, mask induction will nearly always be technically easier.
What is the Mode of Action for “the Chondroproctives” Polysulfated Glycosaminoglycans (Adequan, Cartrophen)
- Stimulates synovial fibropblases to produce hyaluronic acid
- Inhibition of inflammatory mediators (eg proteases, collagenase)
- Improves subchondral blood flow.
Used for Horses and Canine osteoarthritis
What effect would excessive ACh cause?
Overstimulation of the parasympathetic nervous system and the somatic nervous system and maybe even the CNS
- What happens when we suddenly stop cortisone?
- Why would this happen?
- Potentially get a hyperadrencortical crisis
- Exogenous Glucocorticoid eg cortisone (tablets) drive the negative feedback loop meaning if you suddenly stop them there potentially wont be enough cortisol resulting in a hypoadrenocorticalism (addisons) episode
- Ketamine is a GA what is its mode of action ?
- Ketamine is also known as a _________ anaesthetic?
- How is it best administrered?
- Highly complex , part of MOA is antagonist at NDMA receptors (N-Methyl D-aspartatea glutamate receptor) on excitory neurons.
- Disassociative anaesthesia - patient is grossly unresponsive to the environment , yet not asleep.
- Good non-IV bioavailability, non IV injections sting, capable of inducing GA when given IM or SC.
What is the advantage on an inhalant over an injectable GA during an induction ?
- mask induction does not require the animal to be injected . considering most injectable GA are IV administration, mask induction will nearly always be technically easier.
- Maintenace with inhalant is easier than injectable.
- Injectable is quick to induce