What Medications Interact with Birth Control Pills?

Several medications can reduce birth control pill effectiveness by up to 50%. Antibiotics like rifampin, anti-seizure medications including phenytoin and carbamazepine, and HIV medications such as ritonavir are primary culprits. St. John's wort, a common herbal supplement, significantly decreases hormone levels in oral contraceptives. Barbiturates and some antifungal medications also interfere with pill absorption. Additionally, medications that cause vomiting or diarrhea within 3-4 hours of taking your pill can prevent proper absorption. Always inform your healthcare provider about all medications and supplements you're taking to discuss backup contraception methods when necessary.