Week 1 Flashcards
what is pharmacokinetics?
translocation and metabolism of drugs Absorption Distribution Metabolism Elimination
food in, exocrine secretoin, absorption, excretion.
describe Absorption?
oral, most common, can be intravenous straight to plasma
Solublity - water, lipid.
Ionisations status pKa - weak acids and weak bases.
what is Vd?
volume of plasma that would contain the total body content off the drug at the conc equal to the plasma
Vd = amount of drug in body / conc of drug in plasma
drugs with a HIGH Vd have a high conc in extravascular tissues.
describe metabolism?
Phase 1/ Phase 2 reactions.
Drug - Phase 1 - Derivative - Phase 2 - Conjugate , increase in H2O solubility as it goes on.
Phase 1 - describe it?
includes oxidation, hydrolysation, hydrolysis. derivative is made
Phase 2 - desicbe it and give some reactions?
conjugate made common conjugates in cats - glucuronyl - glucorndation sulphate - suplhation methyl - methylation common in dogs - acetyl - acetylation.
Phase 1 - give some common reactions?
reactions - Locations - enzymes oxidation Liver. Cytochrome P450 reduction. lungs hydrolysis skin hydration. kidney
what does Cytochrome P450?
cycle eneyxme reaction
DOGS - greyhounds deficient in subtype of P450,
can use at different doses and frequrenxyx
CATS - deficient in demethyaltion
PIGS - altred metabolic activity
RUMINANTS - plasmasoudoestrane deficiency.
what consequences can occurs form phase 1/2 reactions/
poor bioavaialbilty, larger does needed, marked inter-indivial variation, species, breed, indiviudal etc
what does the induction of micromomal enzymes do?
some drugs induce synthesis of microsomal enzymes , results in ⬆️ metabolism + increase/decrease toxicity.
what is clearance?
effieceny pf irreversible wlimatoin of a drug form the systematic circulation
OR
volume of blood cleaned of a drug per unit time.
what are OCTs and OATs
organic cation transports and organic anion transports.. passes into the gut and removes more waste products
what is enteroheptic circulation?
gut is able to breakdown molecules, glucoropides hydrolysed and reabsorbed - up to 20% of drug.
describe 0 order kinetics?
Sc/St = k
rare in practice
Describe 1st order kinetics?
Sc/St = kC
most drugs
what is half life?
amount of time taken for a quantity to fall to half it value as measured at start of time period
what is affinity?
a measure of the attraction between drug and receptor
what is Efficacy?
the ability of a ligand, once bound, to elicit a response
what is an agonist?
is a chemical that binds to a receptor and activates the receptor to produce a biological response.
what is an antagonist?
type of ligand or drug that avoids or dampens a biological reaction. Upon binding to the receptor, it does not activate.
what are the Types of antagonism?
completive and non-competitive,
physiological
chemical
pharmacokinetic
what is a single compartment model (Pharmacokinetic)
a single, well-stirred compartment into which a drug is introduced and is well eliminated
what is a two compartment model? (pharmacokinetics)
admin i.v. “central compartment
distribute to “peripheral compartment
extra compartments affect time to drug action NOT steady state
name the parameters used to investigate liver damage?
Hepatocellular enzymes
Billary enzymes.
name the hepatocelluler enzymes used for liver investigation?
Alanine aminotransferase
Asparate aminotransferae
Sorbitol dehydrogenase
Glutamate dehydrogenase
describe how Alanine aminotransferase is used for liver damage?
leaks from cytosine of damaged hepatocytes. liver specific.
small animals mainly.
there is a poor correlation between serum levels and hepatic dysfunction.
describe how Asparate aminotransferae is used for lover damage?
cytosolic + mitochondria isoenzymes exist, food in skeletal + cardiac muscle + erythrocytes.
desire how Sorbitol dehydrogenase + Glutamate dehydrogenase r used for liver damage?
both, cytosol (fluid) of hepatocytes
SDH - useful in horse and cattle
GLDH - horse and cattle, sensitive monitor for hepatic injury
how are Biliary enzyme used for liver damage?
alkaline phosphate (ALP) gamma glutamyl transferrace (GGT) = both membrane bound enzymes
how is Alkaline Phosphate (ALP) used for diagnosis of liver damage?
found in hepatocytes, impairment of bile flow, markedly increased ALP activity.
Isoenzymes, hepatic, inerrnal, bone, placental.
what does ⬆️ ALP indicate? in liver?
cholestasis, drug induction, bone remodelling
DOGS - steroid induced ALP unique in dogs
CATS - less capacity for hepatic production of ALP
L.A - wide referee ranges.
how is gamma glytanyl transferase (GGT) used for diagnosis of liver damage?
found in hepostabilty system + renal tables.
useful for cattle, horses and cats
GGT may rise in dogs - recovery costocortiods,
renal disease - GGT found in urine!
what parameters can be used to access hepatic function?
Bilirubin
Bile acids
Albumin Cholesterol Urea Clotting factors glucose
how is Bilirubin used as a parameter for hepatic function?
pigment produced by degeneration of heme proton of haemoglobin. RBCs lyse and heme is converted into bilirubin, is transported to liver, attracts albumin, liver takes up bilirubin it conjugates to be one water soluble and excited put bile duct of large intestine.
describe hyperbilibrumia?
pre-hepatic - haemolysis ⬆️ bilirubin , hepatic uptake, conjugation
Hepatic - anorexia/fasting in horses. may ⬇️ uptake of hepatocytes, inter-hepatic cholestasis
Post-hepatic - bile duct tumours, cholelithiasis, obstructer of bile flow.
what are bile acids?
synthesised form liver form chloerstol. used to solubuse lipids, aid fat digestion. recycled using enterohepatic circulation.
what is bile acid test?
DOGS/CATS - fasting + post prandial
2hrs later - serum bile acids measured
feeds include a bolus of bile acid to be released into intestine
increased bile acids effects?
portosystemic shunts - portal blood bypasses liver, hepatic atrophy.
Liver failure
Cholestrosis - causes relax pf bile acids in blood
bile acids not functional.
what is toxicology?
scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating exposures to toxins and toxicants.
what is poison?
substance which destroy life or injuries health when introduced to a living organism
what is toxicity?
high due or high sensitivity
what is LD?
lethal dose LP50 - dose to kill 50% test population
what is ED?
effective dose - ED50 - does to benefit 50% population
what are the 5 basic routes of intoxication?
ingestion, cularnaous, inhalation, injection, other,
how do you know if an animal has been treated from poison?
breathing, HR and temp stabilised, info form owner, prevent more poison, an antidote has been given.
what is gastric evacuation in an animal?
soon after injection - removes 40-60% ingested matter.
drugs to stimulate CTC to induce vommiting.
what are some products used to cause vomiting after poisoning?
Adsorbents - actiavted charcoal (slurry) acts as a sponge.
Give orally
Chelating agents - bind metal ion, bored ions `re chemically insert, chemical reaction, this preventing poisoning
Carthartics - sodium or magnesium sulphate - pull water into gut and increase movement though gut.
chocolate poison?
chocolate - source: theobromine occurrence: 3rd most common toxicity: white is most with milk the least. NO ANTIDOTE for it.
Rat poison (anticoagulant rodenticides)
1st gen - warfrain (less toxic)
2nd gen - difernancum (highly toxic)
occurrence: usually dogs
toxicity: vitamin K antagonist (reversible tho), interferes with clotting factors
Clinical signs - depression + anorexia, acute ingestion of very high doses = vascular collapse
Diagnosis - prodding clotting time, urine analysis, haemorrhage,
TREATMENT : vitamin K1, menadine, posit K1 (vit k3 not effective, not effective for treating rodenticide toxicity due to its delayed onset of action.)
Antifreeze poison?
attractive taste, common in cats highly mortality.
Toxicity: LD50 metabolites are toxic,
Clinical signs: weaness, vomiting, uncoordintaion, thirst, urine production, blood in urine
Treatment - Ethanol, substitute for ADH enzyme
20% ethanol IV 5.5ml/kg
5% sodium bicarbonate 8.8ml/kg counteracts acidosis caused by glycolic acid
what are some psychoactive drugs?
cocaine, amphetamine, narcotis
occurrence: little documentation but its a risk with sniffer dogs etc.
Toxicity: generally rapid CNS effects
Treatment: decontamination, specific antagonists.
Paracetamol poison?
household supplies,
occurence: rats especially susceptible
LD50 - cats 50-100 mg/kg
N-acetyl-p-benzoysime
clinical signs - facial/pulmonary oedema, cyanosis, lover damage, haemolysis, jaundice,
treatment - decontamination, supportive
N-acetyl-p-benzoysime precursor (toxbox)
Toxbox contains key treatments and antidotes.
what is the VPIS?
Veterinary poisons information service - subscription needed, not public, 12000 cases held,
provides: risk asseemsnts,, lab services, identity tablets, antidote, prefume survaalive.
provides a TOXBOX - activated charcoal - binding toxins
vit K1 - rat poison
intralipid 20%
what is cell injury
adaptive change, reversible cell injury or irreversible cell injury