CONTRACEPTIVES AND ISONIAZID

One or two cases of combined oral contraceptive failure have been reported with isoniazid. However, there is evidence that isoniazid does not cause contraceptive failure when used in combination with other antimycobacterials (without rifampicin (rifampin)). These isolated cases are anecdotal and unconfirmed, and the interaction (if such it is) appears to be very rare.
For guidance on the use of antibacterials with contraceptives, see contraceptives.