FDA Issues ‘Black Box’ Warning for Injectable Contraceptive
FDA on Wednesday said it will add a "black box" warning -- the strongest warning a drug can carry -- to the labeling of Pfizer's Depo-Provera because of evidence that extended use of the injectable contraceptive can cause "significant" bone density loss, the AP/Yahoo! News reports (AP/Yahoo! News, 11/17). Depo-Provera -- which works by releasing a high level of progestin to stop the ovaries from releasing eggs -- is administered by a shot from a health care worker about every three months and has a failure rate of about 1% (Wall Street Journal, 11/18). Although FDA says the drug remains "safe and effective," the agency and Pfizer decided to add the warning label to "ensure that physicians and patients have access to this important information," according to an FDA release (FDA release, 11/17).
The black box warning states that bone density loss increases the longer the drug is used and that such bone density loss is not always completely reversible after use of the drug is discontinued (AP/Yahoo! News, 11/17). In addition, the labeling will warn that patients should not use the drug for more than two years unless all other birth control methods have been deemed inadequate (FDA release, 11/17). FDA issued the warning after reviewing data from two separate studies that showed Depo-Provera's effect on bone density during prolonged use. One study began in 1994 and enrolled 540 women ages 25 to 38. The other study -- which started in 1997 and will continue through 2006 -- enrolled about 400 girls ages 12 to 18 who were taking the drug and is examining ways to reverse bone mineral density loss, according to a Pfizer spokesperson. In addition to the black box warning, Pfizer also is planning to issue a letter to physicians that will explain the effect of long-term use of the contraceptive on bone density, according to the AP/Yahoo! News (AP/Yahoo! News, 11/17).