Miconazole, sold under the brand name Monistat among others, is an antifungal medication used to treat ring worm, pityriasis versicolor, and yeast infections of the skin or vagina. It is used for ring worm of the body, groin (jock itch), and feet (athlete's foot). It is applied to the skin or vagina as a cream or ointment. Common side effects include itchiness or irritation of the area in which it was applied. Use in pregnancy is believed to be safe for the baby. Miconazole is in the imidazole family of medications. It works by decreasing the ability of fungi to make ergosterol, an important part of their cell membrane. Miconazole was patented in 1968 and approved for medical use in 1971. It is on the World Health Organization's List of Essential Medicines. Medical uses Miconazole is mainly used externally for the treatment of ringworm including jock itch and athlete's foot. Internal application is used for oral or vaginal thrush (yeast infection). This oral gel may also be used for the lip disorder angular cheilitis and other associated systems. In the UK, miconazole may be used to treat neonatal oral thrush, while the alternative nystatin is only licensed for patients over the age of one month, but drug interactions are possible. Side effects Miconazole is generally well tolerated. The oral gel can cause dry mouth, nausea and an unpleasant taste in about 1–10% of people. Anaphylactic reactions are rare. The drug prolongs the QT interval. Interactions The substance is partly absorbed in the intestinal tract when used orally, as with the oral gel, and possibly when used vaginally. This can lead to increased concentrations of drugs that are metabolized by the liver enzymes CYP3A4 and CYP2C9, because miconazole inhibits these enzymes. Such interactions occur for example with anticoagulants of the warfarin type, phenytoin, some newer atypical antipsychotics, ciclosporin, and most statins used to treat hypercholesterolemia. These interactions are not relevant for miconazole that is applied to the skin. Contraindications Miconazole is contraindicated for people who use certain drugs that are metabolized by CYP3A4, for the reasons mentioned above: drugs that also prolong the QT interval because of potential problems with the heart rhythm ergot alkaloids statins triazolam and oral midazolam sulfonamides with a potential to cause hypoglycaemia (low blood sugar) Pharmacology Mechanism of action Miconazole inhibits the fungal enzyme 14α-sterol demethylase, resulting in a reduced production of ergosterol. In addition to