Drug Excretion Flashcards
_____ is the major and most important organ of excretion
Kidney
Drug excretion is the _____ elimination of ________ or ______ from the body via various organs of excretion
Irreversible
Unchanged Parent Drugs/ their metabolites
Drugs excreted by large intestine/rectum(biliary and faecal) excretion are:
Vancomycin-antibiotic
Vincristine-anti-cancer drug
In the excretion of drugs via tongue(saliva), ___ drugs are excreted in saliva of PH ___ — ___ as a result of ____ diffusion across cells of the _____ and _____. Examples:
Basic
5.8-8.4
Passive
salivary glands and oral epithelium
Phenytoin, diazepam, theophylline, caffeine & lithium
Drugs excreted via tears?
Mechanism: occurs by ____ diffusion of ____, _____, ______ molecules from plasma across eccrine and ____ glands.
Cytarabine
Passive
unionized , lipophilic, non-protein bound
Lacrimal
Drugs excreted via skin(sweat):
Alcohol, antipyrine, benzoic acid, cocaine, salicylic acid, lead and mercury.
____ is excreted by lungs
ANAESTHETICS
Example of drug excreted by breast(breast milk):
Aspirin
Drugs excreted via Hair:
Methamphetamine
Methoxyphetamine
Phenobarbital
Glomerular filtration filters small molecules of size _____ such as ___, ___, _____ and ______ via pores at the base of glomerulus.
< 20000
Salt
Water
Sugar
Unbound drugs
Tubular reabsorption occurs by ____ while tubular secretion occurs via ______
Passive diffusion
Carrier -mediated
Two types of half life namely:
Biological
Plasma
Define biological half life:
Biological half life is the time taken for substance to lose half of its physiological, pharmacological or radioactive activity
Definition of Plasma half life:
Plasma t1⁄2 is the time required for the plasma
concentration of a drug to be reduced to half.
Plasma half life depends on
Rate of excretion
Metabolism of the drug
Factors affecting drug excretion:
(6 factors)
Lipid solubility
PH
Enterohepatic cycling
Particle size
Protein binding
Renal disease
Lipid solubility decreases excretion except for drugs excreted via the ____
Lungs
Enterohepatic cycling ____ drug excretion and ___ half life
Examples of drugs seen here are:
Reduce
Increase
Tetracycline, chloramphenicol, digitoxin, phenytoin, oestradiol, colchicine, flurbiprofen, leflunomide
What drug inhibits excretion of penicillin by competing with it for tubular secretion at PCT thereby prolonging it’s action?
PROBENECID
Normal kidney function:
100-130ml/min/1.73m2
Kidney function in kidney disease:
<60 ml/min/1.73m2
Kidney function in kidney failure:
<15 ml/min/1.73m2
Drugs
Tetracycline, chloramphenicol, digitoxin, phenytoin, oestradiol, colchicine, flurbiprofen, leflunomide
