CYP Interactions Exam 4 (Seizure, schizophrenia, depression, bipolar)

Question 1

What anticonvulsants decrease the efficacy of estrogen-containing oral contraceptives through inducing CYP 3A4?

Answer 1

Lamotrigine, carbamazepine, clobazam, oxcarbazepine, phenobarbital, phenytoin, primidone, topiramate
Less pronounced: eslicarbazepine, felbamate, rufinamide

Question 2

What anticonvulsants are are a bad choice for smokers due to the induction of CYP 1A2 by tobacco?

Answer 2

Carbamazepine, phenobarbital, phenytoin, primidone

Question 3

What anticonvulsants interact with warfarin by inducing CYP 2C9?

Answer 3

Carbamazepine, phenobarbital, phenytoin, primidone

Question 4

What anticonvulsants interact with clopidogrel by INDUCING CYP 2C19?

Answer 4

Carbamazepine, phenobarbital, phenytoin, primidone

Question 5

What anticonvulsants interact with clopidogrel by INHIBITING CYP 2C19?

Answer 5

Eslicarbazepine, lacosamide, oxcarbazepine, topiramate

Question 6

What anticonvulsant interacts with SSRIs and SNRIs by inhibiting CYP 2D6?

Answer 6

Clobazam

Question 7

What anticonvulsant interacts with lamotrigine through inhibiting UGT?

Answer 7

Valproate

Question 8

What anticonvulsants interact with lamotrigine by inducing UGT?

Answer 8

Carbamazepine, eslicarbazepine, phenobarbital, phenytoin, primidone

Question 9

What antipsychotics are CYP 1A2 substrates and therefore are not ideal in patients who smoke?

Answer 9

Asenapine, clozapine, olanzapine

Question 10

What antipsychotics are CYP 3A4 substrates and may require dose adjustments when given with 3A4 inhibitors/inducers?

Answer 10

Aripiprazole, brexpiprazole, cariprazine, iloperidone, lurasidone, quetiapine

Question 11

What antipsychotics are CYP 2D6 substrates and therefore may require dose adjustments when given with CYP inhibitors/induces?

Answer 11

Aripiprazole, brexpiprazole, iloperidone, risperidone (produces paliperidone)

Question 12

What antipsychotic has no significant CYP metabolism but must be given with food to improve bioavailability?

Answer 12

Ziprasidone, paliperidone (already metabolized form)

Question 13

What antidepressants are substrates of CYP 3A4?

Answer 13

Escitalopram, vilazodone, levomilnacipran, venlafaxine, trazodone

Question 14

What antidepressant has a metabolite that strongly inhibits CYP 3A4?

Answer 14

Fluoxetine–norfluoxetine inhibits

Question 15

What antidepressants interact with clopidogrel through being a substrate of CYP 2C19?

Answer 15

Citalopram, escitalopram, fluoxetine, sertraline, imipramine

Question 16

What antidepressants inhibit CYP 1A2 and therefore interact with duloxetine, a substrate of CYP1A2?

Answer 16

Fluoxetine, fluvoxamine, tranylcypromine

Question 17

What antidepressants inhibit CYP 2D6, an enzyme important for degrading many SSRIs, duloxetine, venlafaxine, and trazodone?

Answer 17

Paroxetine, trazodone, tranylcypromine

Question 18

What antidepressants have no significant CYP interactions?

Answer 18

Desvenlafaxine, milnacipran, isocarboxazid, phenelzine,

Question 19

What drugs increase the risk of toxicity from lithium?

Answer 19

Thiazide diuretics, ACE/ARBs, NSAIDs

Question 20

What drugs decrease the levels of lithium?

Answer 20

Caffeine, osmotic diuretics, sodium bicarbonate, and high sodium intake