Combined hormonal
contraceptives are less reliable during treatment with
rifampicin. Breakthrough bleeding and spotting are common, and pregnancies have occurred. Similarly, progestogen-only oral
contraceptives and emergency hormonal contracep- tives are considered to be less effective in those taking
rifampicin.
For advice on the use of
enzyme inducers, such as rifampicin, and
contraceptives, see
contraceptives. It has been recommended that an alternative or additional form of contraception should also be used for 4 to 8 weeks after stopping
rifampicin.