pharmacology Flashcards
Cytochrome P-450
A key liver enzyme responsible for oxidation/reduction reactions in drug metabolism.
(phase I - microsomal enzyme)
Glucuronidation
A Phase II metabolism reaction that conjugates drugs with glucuronic acid to facilitate inactivation and excretion.
(example : paracetamol)
First-Pass Effect
Liver metabolism before systemic circulation that reduces the bioavailability of orally administered drugs.
Enterohepatic Circulation
Process where drugs cycle between the liver and intestines, prolonging their effects (e.g., Morphine).
Isoniazid (INH) Metabolism
Undergoes Phase II acetylation before Phase I hydrolysis, opposite of most drugs.
(acetylation)
Thiopental by oxidation reaction converting into
Pentobarbital.
Prednisone by reduction reaction converting into
Prednisolone
Prodrug activation where( Codeine ) is metabolized into
Morphine
( Clopidogrel ) by Prodrug activation, requiring liver metabolism to produce
(active thiol metabolite) for antiplatelet effects.
(Methanol) metabolism produces
(Formaldehyde), which can cause blindness and toxicity.
Acetaminophen (Paracetamol)
Overdose leads to (NAPQI accumulation), causing liver failure if glutathione is depleted.
Hepatic Microsomal Enzyme Inducers
Phenytoin, Carbamazepine, Rifampicin
Hepatic Microsomal Enzyme Inhibitors
Grapefruit Juice, Sodium Valproate, Erythromycin, Omeprazole
pseudo-cholinesterase Deficiency
Genetic disorder causing prolonged effects of Succinylcholine, leading to extended neuromuscular blockade.
Gray Baby Syndrome
Fatal condition in neonates due to an inability to metabolize Chloramphenicol, causing toxicity and cyanosis.
Alkalinization of urine enhances excretion of
weak acids (e.g., Aspirin).
Acidification of urine enhances excretion of
weak bases (e.g., Amphetamine).
Ampicillin & Biliary Excretion
Ampicillin is excreted in bile in an active form, making it useful for (Cholecystitis treatment).
Reduce hepatic blood flow???
Propranolol & Cimetidine
Enzyme inducers that accelerate metabolism of multiple drugs, reducing their plasma concentration.
Phenytoin & Carbamazepine
Powerful enzyme inducer,
Rifampicin
Potent enzyme inhibitors, slowing drug metabolism and increasing toxicity risk.
Erythromycin & Omeprazole
non-volatile drugs and metabolites are excreted in
URINE
Neostigmin
ionized - poor absorption
amphelamine
weak base drug
physostigmin
non-ionized - better absorption
digoxin
slow absorption
paracetamol & propranolol
rapid absorption
what is the effect of milk calcium
low oral absorption of tetracyclines
gastroparesis
(e.g in diabetes)
slow gastric emptying
opoids (morphin) & anticholinergics
delay gastric emptying
prokinetics
(e.g, metoclopramide)
accelerate gastric emptying
loperamide
anti-diarrheals
diazepam
basic drug
cholestyramine & charcoal
reduce absorption of many drugs by adsorption
tetracycline
reduce calcium & iron absorption by chelation
lung metabolize
prostagmine & nicotin
G.I.T & gut flora metabolize
tyrmine & histamine
plasma choline esterase inactivate??
acetyl choline