FDA medical bulletin : important information for health professionals from the U.S. Food & Drug Administration最新文献

The Food and Drug Administration approved the first so-called female condom on May 7. Despite limited data on the effectiveness of the Reality Vaginal Pouch in sexually transmitted diseases (STDs) and a relatively high pregnancy rate among users, the device was approved because it is the first barrier contraceptive for women that provides some protection against STDs. The label will be required to emphasize that for "highly effective protection" against STDs, including AIDS, latex condoms for men are the best choice. The panel must also compare the pregnancy rate for the female condom--approximately 26%/year--to rates for other barrier contraceptives, which are lower. For example, the pregnancy rate for male latex condoms is approximately 15%/year. The females condom consists of a lubricated polyurethane sheath with a flexible polyurethane ring on each end. One ring is inserted into the vagina much like a diaphragm; the other remains outside, partially covering the labia. In addition to the labeling restrictions, FDA is also requiring the manufacturer of the product, Wisconsin Pharmacal of Jackson, Wis., to take part in additional effectiveness studies for the product. FDA's decision to approve the female condom was based on a review of clinical data submitted by the manufacturer and the unanimous recommendation of the agency's Obstetrics and Gynecology Devices Advisory Panel at its meeting on December 10, 1992. Wisconsin Pharmacal studies 200 women who used the device for 6 months. The estimated pregnancy rate of 26%/year in the study is believed to have been due in part to improper use of the device by some of the subjects. (The expected rate of pregnancy among women not using any contraceptive method is 85%). Women who use the device correctly each time they have intercourse can expect a lower pregnancy rate.

FDA has approved medroxyprogesterone acetate as Depo Provera Contraceptive Injection, effective for 3 months in preventing pregnancy in women. In clinical studies, the drug's failure rate was less than 1%. However, physicians must ensure that patients receive injections on schedule to prevent pregnancy. The recommended dose is 150 mg administered every 3 months by deep, intramuscular injection in the gluteal or deltoid muscle. Most women in clinical studies of Depo Provera experienced menstrual irregularities. As use continued, amenorrhea became common, reported by 57% of the women by the end of a year of treatment. Other side effects included weight gain, headache, nervousness, abdominal pain or discomfort, dizziness, and asthenia. Physicians should administer the drug only to women found not to be pregnant, because fetal exposure may lead to low birth weight and other problems. Recent data have demonstrated that longterm use may contribute to osteoporosis, and the drug's manufacturer, the Upjohn Company of Kalamazoo, Michigan, will conduct additional research to study this possible side effect. Contraindications are similar to those for other contraceptives and include undiagnosed vaginal bleeding, known or suspected malignancy of breast, thromboembolic disorders, cerebral vascular disease, and liver dysfunction. Depo Provera was developed in the 1960s and has been approved for contraception in many other countries. When FDA first reviewed data on the drug in the 1970s, animal studies raised questions about its potential to cause breast cancer. Since then, longterm controlled clinical studies in other countries have shown a risk of breast cancer comparable to oral contraceptives, and no increased risk for ovarian, liver, or cervical cancer. The studies also showed that the contraceptive injection reduced the risk of endometrial cancer. FDA approved the drug October 29, 1992.

FDA has developed standardized, simplified instructions for all brands of combined estrogen and progestogen oral contraceptives (OCs) to help reduce unplanned pregnancies. FDA asked manufacturers in April to incorporate these changes into patient package inserts as soon as possible. Since current instructions vary significantly from brand to brand, problems can occur when women switch brands and compare instructions. If they become confused, women may either take the pills incorrectly or stop altogether, risking an unwanted pregnancy. In addition to reducing patients' confusion about correct use, the new recommended instructions reflect current research on the effective use of OCs. An important change concerns when women should start taking pills. The new instructions provide only 2 options (current instructions provide more): either start on day 1 of the next normal menstrual cycle ("Day 1 Start") or on the 1st Sunday after the next cycle begins ("Sunday Start"). Although the "Sunday Start" option is popular, the "Day 1 Start" has been shown to be more effective since back-up contraceptive methods are not required for the 1st week, as they are for the "Sunday Start." Other changes in the patient package insert simplify and clarify the instructions when different numbers of pills are missed. Any patient who is unsure about what to do when pills are missed is told to use a back-up method of birth control and to keep taking pills with hormones until she van consult with a health professional. The new labeling also advises women to consult a health professional regarding other methods of contraception if taking a daily pill is a problem. These new directions for patients are for combination pills and do not apply to progestin-only OCs. FDA is still developing new labeling for them. FDA's Fertility and Maternal Health Advisory Committee recommended on FEb. 8, 1991, that the agency ask manufacturers of OCs to make these changes in the patient package insert.