The pill and other drugs.
Drugs may interact with oral contraceptives by influencing their absorption, stimulating or inhibiting their metabolism, or acting through the same or physiologically opposing receptor mechanisms. Breakthrough bleeding and spotting are the warning signs that should encourage enquiry about additional drug taking. The use of powerful enzyme-inducing drugs like phenobarbitone or rifampicin, effectively rules out the use of oral contraception as a reliable method of fertility control. The problem of drug interaction with oral contraceptives should be kept in perspective; the number of reports is still very low.
D000900:Anti-Bacterial Agents; D003276:Contraceptives, Oral / Q000378:metabolism*; D004347:Drug Interactions; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D007668:Kidney / Q000378:metabolism; D011247:Pregnancy; D011485:Protein Binding
D000900:Anti-Bacterial Agents; D003276:Contraceptives, Oral; D004791:Enzyme Inhibitors