Mirena Drug Interactions

Note: The prescribing information of concomitant medications should be consulted to identify potential interactions.
Effects of other medicinal products on Mirena: Interactions can occur with drugs that induce or inhibit microsomal enzymes, which can result in increased or decreased clearance of sex hormones.
Substances increasing the clearance of levonorgestrel, e.g.: Phenytoin, barbiturates, primidone, carbamazepine, rifampicin and possibly also oxcarbazepine, topiramate, felbamate, griseofulvin and products containing St. John's wort.
The influence of these drugs on the contraceptive efficacy of Mirena has not been studied but is not believed to be of major importance due to the local mechanism of action.
Substances with variable effects on the clearance of levonorgestrel: When co-administered with sex hormones, many HIV/HCV protease inhibitors and non-nucleoside reverse transcriptase inhibitors can increase or decrease plasma concentrations of the progestin.
Substances decreasing the clearance of levonorgestrel (enzyme inhibitors), e.g.: Strong and moderate CYP3A4 inhibitors such as azole antifungals (e.g. fluconazole, itraconazole, ketoconazole, voriconazole), verapamil, macrolides (e.g. clarithromycin, erythromycin), diltiazem and grapefruit juice can increase plasma concentrations of the progestin.