Do TB drugs reduce efficacy of birth control pills?

Q: I am taking AKT-4 for tuberculosis. Will this drug reduce the efficacy of my birth control pill? I am supposed to switch drugs soon. Do tuberculosis drugs tend to affect the efficacy of birth-control pills?

A:Anti-TB drugs (especially Rifampicin) could reduce the effect of oral contraceptives and vice versa due to induction of the liver enzymes, which metabolise these drugs. There is a potential risk of the anti-TB drugs reducing the effectiveness of the oral contraceptives and it is recommended that you discuss with your physician regarding the use of an additional non-hormonal means of contraception.