Mirena contains 52 mg of levonorgestrel (LNG). Initially, LNG is released at a dose rate of approximately 20 mcg/day. This rate decreases progressively to half that value after 5 years. Mirena must be removed by the end of the fifth year and can be replaced at the time of removal with a new Mirena if continued contraceptive protection is desired. Drug interactions and warnings include potential interactions with insulin , warfarin (Coumadin) and steroids. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Mirena should not be used during pregnancy. This device can cause severe infection, miscarriage , premature birth , or death of the mother if it is left in place during pregnancy. Tell your doctor right away if you become pregnant while using the Mirena intrauterine system. Small amounts of progestins such as those in Mirena pass into breast milk. If you have recently had a baby and are breastfeeding, wait until your baby is at least 6 weeks old before you start using Mirena.
Sometimes, putative medical adverse effects are regarded as controversial and generate heated discussions in society and lawsuits against drug manufacturers. One example is the recent controversy as to whether autism was linked to the MMR vaccine (or by thiomersal , a mercury -based preservative used in some vaccines ). No link has been found in several large studies, and despite removal of thimerosal from vaccines a decade ago the rate of autism has not decreased as would be expected if it had been the causative agent.