Oral contraceptive Pill (OCP) failure is seen with all except:
Drugs leading to OCP failure are: Rifampicin Tetracyclines Phenytoin Phenobarbitone Antifungals Cephalosporin Ritonavir for HIV (interferes with absorptionn of OCP) Ref: online resources (ncb.nlm.nih.gov)
Rifampicin
Phenobarbitone
Valproate
Phenytoin
Contraception