OC interactions

Question 1

anticonvulsants (phenytoin, carbamasepine)

Answer 1

induce metabolism of OCs- decreased efficacy- 50mcg EE+additional method

Question 2

colesevelam

Answer 2

reduce absorption of OCs- decreased efficacy

Question 3

corticosteroids

Answer 3

OCs inhibit metabolism of steroids- increased steroid side effects

Question 4

penicillins & tetracyclines

Answer 4

alter intestinal flora, reducing circulation of estrogen- decreased efficacy

Question 5

st john’s wort

Answer 5

induce metabolism of OCs- decreased efficacy

Question 6

theophylline

Answer 6

OCs decrease clearance of theopylline- increase theophylline side effects

Question 7

griseofulvin

Answer 7

decreased OC efficacy- use 2 methods

Question 8

NNRTIs

Answer 8

decreased OC efficacy- use IUD

Question 9

protease inhibitors

Answer 9

increased or decreased OC efficacy- use IUD

Question 10

rifampin

Answer 10

decreased OC efficacy- use 2 methods or IUD

Question 11

warfarin

Answer 11

increaed theomboembolic, decreased [progestin]-AVOID hormonal contraceptives

Question 12

stimulants-provigil

Answer 12

decreased OC efficacy- use 2 forms until 1 month after use

Question 13

retinoic acid derivatives

Answer 13

decreased [progestin]- use 2 forms