There seems to be no evidence that the reliability of combined hormonal contracep- tives is affected by isotretinoin, and they are the contraceptive method of choice with these teratogenic drugs. Progestogen-only oral
contraceptives are not generally considered reliable enough for use with teratogenic drugs. The adverse effects of
isotretinoin on lipids may be additive with those of oral
contraceptives, but the importance of this is not known.
Contraceptives should be started one month before
isotretinoin and continued for one month after stopping
isotretinoin. In the USA, it is standard practice to recommend that a second form of contraception, such as a barrier method, should also be used. This is because, even though hormonal methods of contraception are highly effective, they do, on rare occasions, fail.