TABLE 5

Medications That Decrease COC Efficacy

Antibiotics
 Rifampin
Anticonvulsants
 Felbamate
 Ethosuximide
 Primidone
 Phenobarbital
 Phenytoin (Dilantin)
 Carbamazepine
 Oxcarbazepine
 Lamotriginea
 Rufinamidea
 Topiramate
Antidepressants
 St. John’s wortb,c
  • Source: World Health Organization. Medical Eligibility Criteria for Contraceptive Use. 4th ed. Geneva, Switzerland: World Health Organization; 2009.

  • a Fewer data are available for these newer antiepileptic drugs, but available data suggest they can decrease COC effectiveness.

  • b Advantages of COC use generally outweigh the risks.

  • c Murphy PA, Kern SE, Stanczyk FZ, Westhoff CL. Interaction of St. John’s Wort with oral contraceptives: effects on the pharmacokinetics of norethindrone and ethinyl estradiol, ovarian activity and breakthrough bleeding. Contraception. 2005;71(6):402-408.