Pharmacology Flashcards
Indications
reasons for giving a drug to a patient
Contradictions
reasons for not giving a drug to a patient
legend drugs
Prescription drugs
Prescription drugs (mention legend)
Regulated by the FDA and must be labeled with the following statement (or legend):
“Caution: Federal law restricts the use of this drug to use by or on the order of a licensed veterinarian.
veterinarian-client relationship
*The vet has responsibility for
-clinical judgments about the health of the animal and the treatment, and the client has agreed to follow the veterinarian’s instructions.
*The vet has sufficient knowledge of the animal(s) to issue a diagnosis.
-must have seen pet “recently” (typically 6 months)
*The veterinarian must be available for follow-up evaluations of the patient.
Drug regiman
Kind of drug
Route of administration
Dosage
Frequency
Duration
Transdermal meds
- Also called topical drugs
*placed on the skin.
*Some painkillers come as patch
– allows slow absorption of the drug over time
*drugs that penetrate animal skin will often penetrate human skin as well
– where gloves
Bioavailability
The amount of drug that gets absorbed and is available to the patient.
–where the drug goes in the body influenced by it’s characteristics and its relative concentrations
Water-soluble drugs
Tend to stay in the bloodstream, where they can be bound to various proteins (such as albumin) or remain free.
Lipid-soluble drugs
*Absorbed by bodily fats (or lipids).
*Tend to move out of the bloodstream into the interstitial fluid or tissue areas.
*Fat, liver, kidneys, and bone may act as storage sites
Possible drug barrier site
Placenta and bloodbrain barrier
metabolite
What’s produced by the metabolism of a drug
Four processes of medicine transformation
Oxidation -
Reduction -
Hydrolysis -
Conjugation -
Conjugation (transformation of a drug)
Basic concept= joining together two compounds
Example - The drug molecule and glucuronic acid join to make another compound that dissolves more quickly in water (less important)
What may metabolize drugs differently
Cats and young animals
(due to a lack of enzymes)
Drug excretion routes
*Primary routes are liver and kidneys
–through the liver via bile (bile digests fats)
– kidneys via urine
* Other routes
–the mammary
–the lungs,
– the gastrointestinal (GI) tract,
– sweat glands
– saliva
– skin
Residues
Drugs that appear in the animal’s milk or meat products
Therapeutic Dose
The quantity which is required to elicit the desired therapeutic response in the individual
Pharmacodynamics (not drug interaction)
the study of the mechanisms by which drugs produce physiological changes in the body.
agonists (drugs)
Drugs that attach to certain receptors and cause-specific actions
antagonists (drugs)
Drugs that block receptors from being acted on
therapeutic index
**the relationship between a drug’s efficacy and its tendency to produce toxic effects.
**It is expressed as the ratio between the LD50/ED50,
**The LD50 is the dose of a drug that is lethal to 50% of the animals in a dose-related trial.
**The ED50 is the dose of a drug that produces the desired effect in 50% of the animals in a dose-related trial.
Drug labels must contain (6 things)
Drug names (both generic and trade names)
Drug concentration and quantity
Name and address of the manufacturer
Controlled substance status
Manufacturer’s control or lot number
Drug expiration date
Prescription drug records should contain:
Drug names (both generic and trade names)
Drug concentration and quantity
Name and address of the manufacturer
Controlled substance status
Manufacturer’s control or lot number
Drug expiration date
The Animal Medicinal Drug Use Clarification Act (AMDUCA)
Extralabel use of approved veterinary drugs legal under certain well-defined conditions.
FDA policy on compounding
The condition compounding is authorized include:
*a legitimate veterinary medical need
* The need for an appropriate regimen for a particular species, size, gender, or medical condition of the patient
* Lack of an approved animal or human drug
* Not enough time to secure the drug needed to treat the condition
Veterinary Feed Directive (VFD)
Gave the Center for Veterinary Medicine (CVM) the ability to better regulate drugs that go into animal feeds.
Four most common medication routes
Oral
IV (intravenous)
IM (intramscular
SQ (subcutaneous)
Discuss the responsibilities of a veterinary technician in the administration of drug orders.
Ensure it’s the correct drug
Give by correct route at correct time
Monitor the pet
Ask questions if orders aren’t clear
Create/affix labels to meds
Explain meds to clients
Record in medical record
Efficacy
the degree to which a drug produces its desired effects in a patient
Withdrawal time
the amount of time that must elapse between the end of drug therapy and the elimination of that drug from the patient’s tissues or products.
Source of medications
Plants
Bacteria/molds
animals (rare now)
Minerals
synthetic materials
List some of the factors that influence drug absorption.
Process of absorption (passive, active, transported)
pH and ion status of drug
How absorptive is the area the drug is going
Blood supply to area
Solubility of drug (lipids)
Dosage form (liquid, tablet, capsule)
Status of GI tract
Interactions with other meds
Barriers (blood-brain and placenta)
What are three government agencies that regulate the development, approval, and use of animal health products?
The FDA
Environmental Protection Agency (EPA)
U.S. Department of Agriculture (USDA)
What is the purpose of FARAD?
To make sure that food animal products are safe for humans by providing information and education materials about drugs and their effects on animals
The Food Animal Residue Avoidance Databank
Compounding
Combining, mixing, or altering ingredients to create a different dosage form other than what is approved by the FDA to accommodate a specific patient’s needs
Classes of Drug interactions
pharmacokinetic
pharmacodynamic
pharmaceutic.
pharmacokinetic interaction
complex series of events that occurs once a drug is administered to the patient,
influences by the manner in which the drug is given, some routes have limitation
pharmacodynamic drug interaction
interaction is one in which the action or effect of one drug is altered by another
pharmaceutic interaction
when physical or chemical reactions take place as a result of mixing of drugs in a syringe or other container.
Once a drug has been biotransformed, it is called a _____
metabolite.
List the six practices recommended by the AVMA for the safe disposal of unwanted drugs.
- Incinerate unwanted drugs when possible.
- Unused drugs should be sent to the landfill when incineration is not possible.
- Never flush unwanted pharmaceuticals down the toilet or drain.
- Maintain close inventory control.
- Always follow federal and state guidelines.
- Educate clients on proper disposal.
Cerumen
A waxy secretion of the glands of the external ear canal.
Counterirritant
An agent that produces superficial irritation that is intended to relieve some other irritation.
Elixir
compound liquid medications held in solution by alcohol, contains flavoring and sweeteners to help mask the taste of the drug
Emulsion
A medicinal agent that consists of oily substances dispersed in an aqueous medium with an additive to stabilize the dispersion.
must be shaken to mix
Enteric coating
Acid resistant coating on a tablet that prevents it from being dissolved in an acid environment such as the stomach and are activated (dissolved) only when they reach an alkaline environment such as the small intestine.
Intravenous bolus
in which a single, precise amount of medication is given one time
Intravenous infusion
given at a slower rate over an extended period of time
Liniment
medicinal preparations for use on the skin as a counterirritant or to relieve pain.
Ointment
-a semisolid preparation of oil and water, plus a medicinal agent.
-The water in an ointment evaporates after application and leaves the drug behind on the skin’s surface
Speculum
An instrument for dilating a body orifice or cavity
Suspension (pharmacology)
Contains insoluble material suspended in a liquid
6 rights for drug administration
- Right patient
- Right drug—check label three times before administering the drug
- Right dose
- Right route
- Right time and frequency
- Right documentation
Categories - Routes of medication administration
Parenteral
Oral
Topical
Inhaled
List Oral med types and methods of medication
Pills/tablets
liquid medication through syringe
by hand or pill gun
using a speculum
Orogastric
nasogastric route
syringes (dribbled or injected)
Controlled drug laws
*Every vet that prescribes must be registered with DEA (good for 3 years)
* The upper right corner of the original container of controlled substances should show a code containing a capital C (controlled), followed by a Roman numeral
– Roman numerals I - V (V having lowest abuse potential)
* Records must also show the flow of controlled substances into and out of the practice including when drugs are acquired, inventoried, stolen, lost, or distributed.
macrodrip drip rate
10 drops, 15 drops, and 20 drops per ml.
micro drip rate
60gtt/nl
drugs that stimulate the action of neurotransmitters often end with
End with -mimetics
think (mime)
drugs that disrupt neurotransmitter end with
-lytics.
(think lyse)
Autonomic System Receptors
Its main receptors are alpha-1, alpha-2, beta-1, and beta-2 receptors.
Autonomic System neurotransmitters
Are epinephrine (adrenaline), norepinephrine, and dopamine.
Parasympathetic system neurotransmitters
acetylcholine.
Parasympathetic system receptors
Its main receptors are nicotinic and muscarinic.
Cholinergic agents can be used to
Primary focus- Increase of GI activity (examples control vomiting, treat urinary retention)
Bonus knowledge
They can also
*Help diagnose myasthenia gravis (a neuromuscular disease that causes muscle weakness and breathing problems)
*Reduce eye pressures with glaucoma
Cholinergic agents mimic and stimulate
acetylcholine and simulate receptor sites of the parasympathetic system.
Anticholinergic agents block
the action of acetylcholine at muscarinic receptors , which inhibits the simulation of the parasympathetic system
Anticholinergic agents (general)
Also called cholinergic blocking agents
Decrease GI motility,
Dry secretions
Dilate pupils
Prevent or treat bradycardia.
Adrenergic agents actions (receptors)
Cause excitement in alpha receptors and inhibitory responses in beta receptors.
Bonus - Epinephrine and neuroepinephrine are the neurotransmitter for adrenergic sites.
Adrenergic agents physiological effects (6 things)
- To stimulate the heart
- To reverse the hypotension and bronchoconstriction of anaphylactic shock
- To correct vasoconstriction- hypotension, prolong local anesthetics and capillary bleeding
- To treat urinary incontinence
- To reduce mucous membrane congestion (vasoconstriction) in allergic conditions
- To treat glaucoma (- Bonus — alpha stimulation increases the outflow of and beta stimulation decreases the production of aqueous humor)
Adrenergic blocking agents (related to nervous system)
Are used to disrupt/inhibit the activity of the sympathetic nervous system.
Barbiturates
Depress the CNS,
One of the oldest classes of drugs,
used to induce general anesthesia, as a sedative, an anticonvulsant, and in euthanasia solution.
metabolized by the liver.
ultra short acting barbiturates
*Duration of action of five to 30 minutes
*rapidly absorbed into the brain, and then redistributed into the body fat,
With multiple doses it can build up in the body fat and prolong recovery, especially in sight hounds because of their lack of body fat.
short acting barbiturates
Duration of action of 45 minutes to 1.5 hours
Long acting barbiturates
A duration of action of 8 to 12 hours
One example is phenobarbital
Barbiturates - warnings
Depressive effect on the respiratory and cardiovascular systems.
No reversal for these drugs, so the liver must metabolize the drug in order for the body to eliminate it.
Tranquilizers
*Depress the CNS
*used for calming/sedating, some have analgesic,
*used in combination with other types of drugs like opioids as pre-medications.
Phenothiazine tranquilizers, such as acepromazine (processed by liver) or chlorpromazine (processed by liver), will produce sedation without significant analgesia
Dissociative agents
- Work on CNS
*secreted through kidneys
*Used for sedation, restraint, analgesia, and anesthesia.
Dissociative agents may be combined with__
With other drugs such as a tranquilizer or an opioid for anesthesia.
If used alone they only immobilize the animal and do not provide any analgesia or surgical anesthesia.
Dissociative agents side effects and warnings
respiratory depression, convulsions, and seizure like activity.
Eyes remain open so lube them
Burns when injected intramuscularly
Opioid agonists (how used etc)
produce analgesia and sedation
work on deep centers of the brain
Many uses when used alone, but many more when used in combination with a tranquilizer.
Low doses are used to treat conditions such as diarrhea or coughing because they reduce peristalsis and segmental contraction (muscle contraction) and depress the cough center of the brain.
example - tramadol
peristalsis
the involuntary constriction and relaxation of the muscles of the intestine or another canal, creating wave-like movements that push the contents of the canal forward.
Opioid contradictions and cautions
Mostly processed through the liver
Respiratory depression
GI Symptoms
Panting
Excitement- particularly in horses and cats and
–sometimes dogs if given IV rapidly.
Opioid antagonists
- Opioid antagonists block the effects of opioids by binding with opiate receptors, displacing narcotic molecules already present, and preventing further narcotic binding at the sites
-work very quickly, but only have a duration of one to two hours.
-Adverse effects for this classification of drug are rare if used at the correct dose.
Example - Naloxone (processed by liver)
CNS stimulants.
*Stimulate CNS receptors
*Used to treat cardiac and respiratory depression.
*Adverse effects is a rare if used correctly.
Epinephrine:
Stimulates all receptors
is a Catecholamine -
Primarily processed through the liver
Adverse Side Effects of Anticholinergic (5 things)
Overdoses can cause:
mental issues- drowsiness, disorientation, anxiety
tachycardia,
constipation
photophobia,
burning at the injection site.
Adrenergic adverse effects (4 things plus one)
include tachycardia, hypertension, nervousness, and cardiac arrhythmias..
pulmonary edema may occur with an overdose.
Enteral Route of medical admin
Oral
sublingual
Rectal
Alpha-2 Agonists
CNS agents
Sedative analgesics used commonly in veterinary medicine. -(this is the main thing to remember)
Dexmedetomidine is an example (not important)
neuroleptanalgesic are used for
produce reduced awareness and analgesia in which the patient may or may not remain conscious.
Useful for restraint, diagnostic procedures, as a preanesthetic, or for minor surgical procedures
MAC (anesthesia)
- Minimum alveolar concentration (MAC),
*a measure of potency - the alveolar concentration that prevents gross purposeful movement in 50% of patients in response to a standardized painful stimulus.
*Lower numbers indicate more potent agents.
Neuromuscular Blocking Drugs
Muscle relaxants,
interfere with neuromuscular transmission of impulses
used as an adjunct to general anesthesia.
Provide no analgesia or sedation.
stop ventilation, and this makes ventilation and constant patient monitoring necessary
The five neurotransmitters of clinical importance in behavioral pharmacotherapy are
acetylcholine, dopamine, norepinephrine, serotonin, and GABA.
Euthanasia Agents
Rapid unconsciousness without struggle
Example pentobarbital.
What do Muscarinic receptors do(4)
decrease heart activity
Increase gi and urinary activity
cause bronchoconstriction
increase secretions -bronchial salivary and sweat glands,
nicotinic receptors
Impacts sleep/consciousness
Causes skeletal muscle to contract.
Oxidation (med transformation
loss of electrons in the drug’s chemical makeup, makes a drug
Reduction (med transformation)
gain of electrons in the drug’s chemical makeup
Hydrolisis
splitting of the drug’s molecule and the addition of water molecules to each split portion
Types of injections
Intravenous (IV)
Intramuscular (IM)
Subcutaneous (SQ or SC)
Intradermal (ID)
Intraperitoneal (IP)
Intraarterial (IA)
Intraarticular
Intracardiac
Intramedullary
Epidural/subdural
Why are residues important to know about
some people may be
allergic to the drug residue and have a reaction to it, causes bacteria to become resistant to certain
antibiotics and may also cause cancer in some humans
How do drugs produce physiological changes
Drugs combine with parts of the cell membrane or with internal parts of the cell to cause
changes in how that cell functions.
Drugs may increase or decrease the activity of specific cells or tissues
formulary
- is a book that contains drug dosages and a listing of adverse reactions
Controlled drug log
enforced by DEA
Date of prescription
Owner and patient name
Drug name
Amount dispensed and strength of the drug
Initials of dispensing doctor
Drugs affect neurons by
Drugs interfere with the way neurons send, receive, and process signals via neurotransmitters.
Catecholamines
act by stimulating the sympathetic nervous system to
Increase the force and rate of heart contractions
Constrict peripheral blood vessels (which increases blood pressure)
Elevate blood glucose levels
processed by the liver
Catecholamine examples (4)
epinephrine, isoproterenol, dopamine, and dobutamine
Catecholamine side effects
Side effects: Side effects include tachycardia, dyspnea, and wide ranges of blood pressure changes
Types of syringes
Slip tip – most common in vet med
Luer lock - have a screw top that secures the needle to the syringe, excellent for injecting thick fluids
Eccentric tip - used when injecting larger volumes (greater than 20 ml) into a vein
Catheter tip – good for oral feedings or for feeding with catheter
beta-1 adrenergic receptors
The beta-1 adrenergic receptor is the dominant receptor in heart
–(less important) equally sensitive to epinephrine and norepinephrine,
beta-2 adrenergic receptors are responsible for relaxation of vascular, uterine, and airway smooth muscle
–(less important) less sensitive to norepinephrine as compared to epinephrine
Intravenous (IV)
takes effect almost immediately
shortest duration
-Reaches peak plasma concentration as soon as the drug enters systemic circulation
-Useful for irritating drugs d/t the diluting effect of blood
-Administer IV drugs slowly to lessen toxic or allergic rxn
-Oil based and drugs with suspended particles should not be given IV d/t possible embolism
-Caution of extravasation which may cause phlebitis
Intramuscular (IM)
-Slower onset than IV
-Longer duration than IV (Onset of action is inversely related to duration of action)
-Irritating drugs should not be administered IM
-Always apply back pressure before injection to ensure no blood vessel involvement
Depot preparation
When a drug is placed in a solution which delays its absorption.
Typically injections
Subcutaneous (SQ or SC)
-Slower onset
-Slightly longer duration
-Absorption rate is slower as the drug must diffuse through the SQ tissue to reach the capillaries and then be absorbed into systemic circulation
-Irritating and hyperosmotic solutions should not be administered SQ
-Quantities of the drug to be administer should be considered to prevent possible dissection of the skin from underlying tissue leading to skin sloughing
Intradermal (ID)
-Injection of drugs into the skin
-Used typically for tuberculosis and allergy testing
Intraperitoneal (IP)
-Administration of drugs into the abdominal cavity
-Onset and duration are variable
-Used to administer fluids, blood, and other medications
-Caution should be used d/t possible adhesion or puncture of abdominal organs
Intraarterial (IA)
-Injection into an artery
-Seldom used
-Caution must be taken in horses; injection into the carotid results in direct delivery to the brain causes seizures or death
Intraarticular
-Injection of drug into a joint
-Used to treat inflammatory condition of the joint
-Requires sterile technique
-Typically DVM only
Intracardiac
-Injection of drug into the heart
-Immediate access to the bloodstream
-Used in cases of CPR and euthanasia
Intramedullary
- Injection of drug into the bone marrow
-Seldom used
-Bones typically used: femur and humerus
-Used to provide blood or fluids to animals with very small or damaged veins, or extreme hypotension
-Also sometimes called intraosseous
Epidural/subdural
-Spinal anesthesia
-Epidural- Administered outside the dura mater (meninges) but inside the spinal canal
-Subdural - Administered into the cerebrospinal fluid
-Typically DVM only
Opioid Agonists receptors
Mu - pain regulating parts of the brain (less important - contributes to analgesia, euphoria, respiratory depression, physical dependence, and hypothermic actions)
Sigma - responsible for struggling, whining, hallucinations, and mydriatic effects
Delta - modify Mu receptor activity (less important- contribute to analgesia)
Kappa - the cerebral cortex and spinal cord ( less important - contributes to analgesia, sedation, depression, and miosis)
Opioid types and examples
Natural - Example: Morphine
synthetic: Butorphanol, Apomorphine
