Levonorgestrel and ethinyl estradiol and Rifampin interaction
Levonorgestrel and ethinyl estradiol and Rifampin: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Levonorgestrel and ethinyl estradiol (Tyblume) label · effective 2026-08-27
Enzyme inducers (e.g., CYP3A4) : May decrease the effectiveness of TYBLUME or increase breakthrough bleeding.
Metabolic Enzyme Inducers Clinical effect Concomitant use of CHCs with metabolic enzyme inducers may decrease the plasma concentrations of the estrogen and/or progestin component of CHCs [see Clinical Pharmacology (12.3) ] .
Examples Aprepitant, barbiturates, bosentan, carbamazepine, efavirenz, felbamate, griseofulvin, oxcarbazepine, phenytoin, rifampin, primidone, phenylbutazone, rifabutin, rufinamide, topiramate, products containing St.
Counsel patients to use a back-up or alternative method of contraception when enzyme inducers are used with TYBLUME.
Prevention or management Counsel females to use an alternative method of contraception or a backup method when enzyme inducers are used with CHCs.
From the Rifampin (Rifadin IV) label · effective 2026-05-27
Telaprevir Decrease AUC by 92% Systemic Hormonal Contraceptives Prevention or Management: Advise patients to change to non-hormonal methods of birth control during rifampin therapy Estrogens Decrease exposure Progestins Anticonvulsants Phenytoin Administered with rifampin 450 mg daily Decrease exposure Antiarrhythmics Disopyramide Decrease exposure Mexiletine…
Decrease AUC by 56% Narcotic Analgesics Oxycodone Decrease AUC by 86% Morphine Decrease exposure Progestin Antagonist Mifepristone Prevention or Management: Refer to the posttreatment assessment in the mifepristone prescribing information to verify that treatment has been successful.
The patient should be advised that the reliability of oral or other systemic hormonal contraceptives may be affected; consideration should be given to using alternative contraceptive measures.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.