00 Drug Interactions Flashcards Preview

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Flashcards in 00 Drug Interactions Deck (18):
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

What can happen is Azole antifungals are given with Cola and other acidic drinks and foods?

May increase absorption and levels of the azole antifungals