CYP

Question 1

CYP “inhibitors”

Answer 1

decrease [enzyme] –> decreases activity –> increases [drug]

Question 2

CYP “inducers”

Answer 2

increases [enzyme] –> increases activity –> decreases [drug]

Question 3

CYP1A2 substrates

Answer 3

1. TCAs (amitriptyline, clomiprimine, desipramine, imipramine)
2. duloxetine (SNRI)
3. theophylline

Question 4

CYP1A2 inhibitors

Answer 4

1. amiodarone*
2. cimetidine
3. ciprofloxacin
4. estrogens (HRT & OC)

Question 5

CYP1A2 inducers

Answer 5

1. carbamazepine/phenytoin (autoinducers)
2. rifampin (TB)
3. smoking

Question 6

CYP2C8 or C9 substrates

Answer 6

1. carvedilol* (non-selective B blocker)
2. phenytoin
3. pioglitazone (diabetic med)
4. TCAs (amitriptyline, clomipramine, desipramine, imipramine)
5. warfarin*

Question 7

CYP2C8 or C9 inhibitors

Answer 7

1. amiodarone
2. gemfibrozil/fenofibrate (dec TG)
3. fluconazole
4. metronidazole (for C. diff, anaerobes)
5. TMP-SMX
6. clopidogrel
7. valproate (anti-seizure, teratogen)

Question 8

CYP2C8 or C9 inducers

Answer 8

1. phenytoin/carbamazepine
2. rifampin
3. St. John’s wart
   * same as CYP2C19, CYP3A4 and P-gp (+dexamethasone)

Question 9

CYP2C19 substrates

Answer 9

1. phenytoin
2. citalopram*
3. clopidogrel*
4. most PPIs (ie omeprazole)*
5. most TCAs (amitriptyline, clomipramine, desipramine, imipramine)

Question 10

CYP2C19 inhibitors

Answer 10

1. fluconazole
2. fluoxetine
3. cimetidine
4. gemfibrozil
5. omeprazole/esomeprazole*

Question 11

CYP2C19 inducers

Answer 11

1. phenytoin/carbamazepine
2. rifampin
3. St. John’s Wart

Question 12

CYP2D6 substrates

Answer 12

1. atypical antipsychotics (aripiprazole, risperidone, etc)
2. codeine*
3. fluoxetine*, paroxetine, duloxetine (SSRIs)
4. metoprolol*
5. most TCAs (amitriptyline, imipramine, clomipramine, desipramine)

Question 13

CYP2D6 inhibitors

Answer 13

1. amiodarone
2. antidepressants (fluoxetine*, sertraline, paroxotine, duloxetine, buproprion)
3. cimetidine (PPI)

Question 14

CYP2D6 inducers

Answer 14

NOT an inducible enzyme!

Question 15

CYP3A4 substrates

Answer 15

1. apixaban/rivaroxaban
2. amiodarone
3. BZDs (most)
4. carbamazepine
5. CCBs (amlodipine, verapamil, diltiazem)
6. clarithromycin
7. cyclosporine, tacrolimus, sirolimus (last 2 are transplant meds)
8. estrogens
9. protease inhibitors (ex. ritonavir)
10. PDE5 inhibitors (sildanafil, tadalafil, vardenafil
11. OCPs
12. opioids (hydrocodone, oxycodone)
13. SSRIs (citalopram, paroxetine, sertraline)
14. theophylline

Question 16

CYP3A4 inhibitors

Answer 16

1. amiodarone
2. non-DHP CCBs (verapamil, diltiazem)
3. cimetidine
4. clarithromycin
5. fluconazole
6. grapefruit juice*
7. protease inhibitors (ritonavir)

Question 17

CYP3A4 inducers

Answer 17

1. phenytoin/carbamazepine
2. rifampin
3. St. John’s Wart
   * same as CYP2C19, CYP2C8 or C9 and P-gp (+dexamethasone)*

Question 18

what is p-glycoprotein? Many p-gp substrates are also _____ substrates.

Answer 18

drug efflux pump found in liver, kidney, BBBs, and cancer cells–> pumps drugs out of cells and into gut, bile, and/or urine for excretion–think of it as a defense against potential poisons

-CYP3A4 substrates; for most p-gp interactions, CYP450 enzyme inhibition or induction is also involved

Question 19

p-gp substrates

Answer 19

1. amiodarone
2. atorvastatin/simvastatin
3. carbamazepine/phenytoin
4. dabigatran/rivaroxaban
5. digoxin
6. estrogen
7. omeprazole
8. paroxetine/sertraline
9. many chemotherapeutics

Question 20

p-gp inhibitors

Answer 20

1. amiodarone
2. carvedilol
3. clarithromycin
4. diltiazem/verapamil

Question 21

p-gp inducers

Answer 21

1. carbamazepine/phenytoin
2. dexamethasone
3. rifampin
4. St. John’s wart
   * same as CYP3A4, CYP2C8 or 9, CYP2C19, (-) dexamethasone*