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.
One concept to reduce the adverse effects of opioids is the use of very small doses of opioid antagonists. 25 – 28 The rationale is that agents such as naloxone (Narcan) have a biphasic effect whereby very low doses reduce the incidence of opioid adverse effects and may augment the analgesic effect. 25 , 28 Much of the data are limited to the inpatient setting with intravenous administration of the opioid antagonist. 25 – 27 Concomitant administration of intravenous naloxone with morphine infusions has been studied, but the results have been mixed. 25 – 27 More research is needed before this treatment is implemented as part of routine practice.
C-C chemokine receptors on CD4 cells include CCR5 (R5) and CXCR4 (X4). Maraviroc, an entry inhibitor, is the only available CCR5 antagonist. It is approved for use in both treatment-naive and treatment-experienced patients. 18 , 19 Maraviroc works only on R5 cells; therefore, an R5 tropism test should be performed before initiating therapy with maraviroc. 1 Maraviroc is as effective as efavirenz when each drug is combined with lamivudine/zidovudine (Combivir). However, maraviroc is better tolerated; percent of patients discontinued therapy with efavirenz because of adverse effects, whereas only percent discontinued maraviroc. 20 Compared with patients taking efavirenz, those receiving maraviroc have more cases of bronchitis and nasopharyngitis. Patients taking maraviroc also report more fever and esophageal candidiasis, but fewer headache symptoms than those receiving placebo. 18 Lipid profiles in patients receiving maraviroc are also better compared with those receiving efavirenz. Studies of interactions with other medications are limited.