Drug Ix and stuff Flashcards
Enzyme Inducers (remember CRAPGPS)
Carbamazepine
Rifampicin
Alcohol - chronic
Phenytoin
Griseofulvin
Phenobarbital
Sulphonylureas
Enzyme Inhibitors (remember SICKFACES.COM
Sodium Valproate
Isoniazid
Cimetidine
Ketoconazole
Fluconazole
Alcohol - acute/binging
Chloramphenicol
Erythromycin
Sulfonamides
Ciprofloxacin
Omeprazole
Metronidazole
Warfarin with naproxen
Nap displaces W from plasma protein binding sites - more free warfarin = ++ effect
NSAIDs bind to albumin dominantly
Doxycycline with Iron
iron decreases abs. of tetracycline abx; tetracyclines bind to Fe strongly => poorly soluble chelate = less readily absorbed by GIT = decreased serum conc
Phenytoin
Phenytoin is CYP3A4 inducer => effect of COC is decreased (up to 50%)
Must use alt. method of contraception; IUD, depots, barrier. For less than 2 months use of phenytoin, consider additional consistent use of condoms during and for at least 28 days after stopping phenytoin.
MTX with NSAIDs
Competition at the proximal tubules. MTX is cleared unchanged, but NSAIDs can increase MTX concentration due to nephrotoxic effect; MTX clearance reduces by approx 40% after ibuprofen use. Avoid NSAIDs with MTX - use alt analgesic or monitor MTX levels or observe for toxic effects if NSAID use is unavoidable
Omeprazole with clopidogrel
Decrease antiplatelet effect; omeprazole is enzyme inhibitor and clop is a prodrug
SSRI with NSAIDs
Increased risk of upper GI bleeding
MTX with trimethoprim (TMP)
Bone marrow suppression eventually leading to pancytopenia
Verapamil + BBs (inlcuding ocular)
Cardiac depression
ACEi + K-sparing diuretics (spironolactone, aka an MRA drug)
increased risk of hyperkalaemia and acute kidney injury
Clarithromycin with simvastatin
Clarithro inhibits CYP3A4, so increased conc of simvastatin, 8-10x increase with multiple doses of clarithro, or 4x increase with single dose of clarithro. Toxicity - myopathies and rhabdomyolysis. Withhold simvastatin while administering clarithro
