The concomitant use of oestrogens with progestogens may rendered less effective and an increased incidence of breakthrough bleeding may occur by virtue of drug interaction with rifampicin, isoniazid, ampicillin, tetracycline, neomycin, penicillin, chloramphenicol, sulphonamides, nitrofurantoin, barbiturates, phenytoin, primidone, analgesics, tranquilisers, antimigraine preparations and antihistamines. They may also alter the effectiveness of drugs such as oral anticoagulants, anti-convulsants, tricyclic anti-depressants, anti-hypertensive agents (e.g. guanethidine), vitamins, hypoglycaemic agents, tranquilisers, hypnotic preparations and theophylline.
Register or sign in to continue
Asia's one-stop resource for medical news, clinical reference and education
Sign Out
