Abstract

PIP: Methotrexate, a folic acid antagonist, is approved by the US Food and Drug Administration for use in rheumatoid arthritis, psoriasis, and various types of cancer, including choriocarcinoma, and has also been used to terminate ectopic pregnancies. Misoprostol, a prostaglandin, is approved for the prevention of gastric ulcers induced by nonsteroidal anti-inflammatory drugs. In France, the UK, and Sweden, misoprostol and another prostaglandin is used with mifepristone (RU486) to induce abortion in early pregnancy. Recent articles in the press have suggested that in early pregnancy, an intramuscular injection of methotrexate and oral or vaginal administration of misoprostol offers a medical alternative to a surgically induced abortion. This paper describes the mechanisms of action, pharmacokinetics, clinical use, and adverse effects of the two drugs. It is concluded that an intramuscular injection of methotrexate followed up to seven days later by the intravaginal administration of misoprostol can terminate an early intrauterine pregnancy. Headache, nausea, vomiting, diarrhea, and prolonged bleeding have occurred. However, in the few studies published to date, no serious complications have been reported.