Flashcards in 00 Drug Interactions Deck (18)
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1
Which enzyme is Warfarin metabolized by?
CYP 2C9
2
What is one of the strongest and broadest enzyme inducers?
Rifampin (many medications given with this will have to have higher doses)
3
Which enzymes do many pain and psychiatric drugs go through?
CYP 2D6
4
What are some of the strong P-gp INHIBITORS?
Azoles (keto-, itraconazole), Verapamil, Macrolides (Clarithro-, erythromycin)
5
What are some of the strong P-gp INDUCERS?
Rifampin, Carbamazepine, Phenytoin, St. Johns Wort
6
Quick Study Tool: PS PORCS (Big CYP Inducers)
Phenytoin, Smoking, Phenobarbital, Oxcarbazepine, Rifampin, Carbamazepine, St. Johns Wort
7
Quick Study Tool: G <3 PACMAN (Big Inhibitors)
Grapefruit, Protease Inhibitors (ritonavir, etc.), Azoles (fluconazole, itraconazole, ketoconazole, etc.), Cyclosporine & Cimetidine, Macrolides (clarithromycin, erythromycin, but not azithromycin), Amiodarone, Non-DHP CCBs (Diltiazem and Verapamil)
8
What are some significant drug interactions that can be seen with Amiodarone?
Digoxin and Warfarin (likely to be given with amiodarone d/t heart failure/arrhythmia). Digoxin and Warfarin dose will need to be decreased
9
What can happen if Warfarin is given with Ginseng?
May decrease the effectiveness of Warfarin (seng, like sink: drains warfarin)
10
What can happen if Warfarin is given with Thyroid Hormones?
Altered INR (incr or decr) - usually increases warfarin effects - Monitor INR
11
What can happen if Bactrim is given with Phenytoin or Methotrexate?
Can increase the Phenytoin/MTX concentrations, increasing toxicity
12
What can happen if Digoxin is given with Cholestyramine or Colestipol?
Decrease levels of digoxin (decreased GI absorption d/t binding and also interruption of enterohepatic recycling of digoxin)
13
What can happen if ACE-Is are given with Potassium-sparing diuretics or Potassium supplements?
May increase serum potassium concentration, especially in renal impaired patients
14
What can happen if ACE-Is are given with Lithium?
Increase levels of lithium by 200-300% (dose-related)
15
What drugs can increase Lithium levels?
STAND: decreased Sodium intake, Thiazides, ACE-I, NSAIDs, Dehydration
16
What can happen if Valproic Acid is given with Phenobarbital or Lamotrigine?
Increases Phenobarbital or Lamotrigine levels
17
What can happen if TCAs are given with MAO-Is?
May lead to hypertensive crisis
18
