Drug Elimination Flashcards
Drug elimination is essential no matter the route of administration. T/F
True
What is elimination?
The irreversible removal of metabolized and unmetabolized xenobiotics from the body.
What are the types of elimination?
Systemic elimination
Pre-systemic elimination
What is systemic elimination?
Drug eliminated form systemic circulation.
What is pre-systemic elimination?
Drug eliminated before entry into systemic circulation. Drugs eliminated by first pass effect.
What are the routes of elimination?
Kidneys/Urine Bile/Feces Lungs/Exhalation Breast Milk Skin/Sweat Tears Hair Saliva
What is the primary excretory organ?
Kidneys
What is the primary route for polar drugs and metabolites to be eliminated?
Kidneys
Non-polar drugs(phenytoin) are subject to tubular reabsorption.
What is the primary route for lipid-soluble drugs plus less polar drugs and metabolites to be eliminated?
Bile/Feces
What is the primary route for inhaled anesthetics to be eliminated?
Lungs
Why is breast milk clinically important even though it is not a major route of elimination?
Because drugs can be passed from mother to nursing infant.
Why is skin/sweat, saliva, or hair clinically important even though it is not a major route of elimination?
It may be used for monitoring or testing.
Why is tears clinically important even though it is not a major route of elimination?
It may be of concern to contact lens wearers.
What test can be used for hair?
Psychemedics PDT-90 test to test for marijuana, ecstasy, cocaine, crack, heroin, methamphetamine, phencyclidine (PCP or angel dust) for up to 3 months.
What are examples of drugs that are eliminated through the kidneys?
Vancomycin, atenolol, ampillicin (polar drugs with CA and amide)
Renal excretion is affected by?
Kidney disease Glomerular Filtration Rate Extent of back diffusion (unionized drug) or reabsorption Active Tubular secretion Tubular pH
What needs to be taken in to consideration when a patient has chronic kidney disease (CDK), HBP, or diabetes?
Certain drugs dose may need to be adjusted. Aminoglycoside antibiotics (Amikacin, Tobramycin) Cephalosporin antibiotics (Ceftazidime, Procainamide)
What elimination occurs through glomerular filtration?
Low MW (
What elimination occurs through tubular reabsorption?
Can be affected by pH change
Un-ionized drug is reabsorbed into plasma (Mostly passive back diffusion)
What elimination occurs through tubular secretion?
Kidney & GI OATPs, POTs, PGPs, MRP2 - are involved in Secretion and reabsorption.
Inhibitors/Inducers will impact drug elimination.