FRIDAY, Jan. 18 (HealthDay News) -- A birth control skin patch used by many American women carries a risk of serious blood clots that is higher than the risk already recognized for the birth control pill, the U.S. Food and Drug Administration warned late Friday.

Based on the results of a new study that discovered the increased danger, the agency said it has approved changes to the labeling for the Ortho Evra Contraceptive Transdermal Patch, to better warn women and their doctors of the potential risk.

"For women that choose to use contraceptives, it is important that they thoroughly discuss with their health-care providers the risks and benefits involved," Dr. Janet Woodcock, deputy commissioner for scientific and medical programs at the FDA, said in a statement.

The warning followed reports out of Canada last week of two deaths, one heart attack and 16 cases of blood clots since 2004 among women who used the patch.

Approved by the FDA in 2001, the patch is sold by prescription and releases ethinyl estradiol (a type of estrogen), and a progestin called norelgestromin via the skin into the bloodstream. But the FDA noted that the body processes hormones delivered in this way differently than hormones delivered in pill form, so that "women using the product will be exposed to about 60 percent more estrogen than if they were using typical birth control pills."

Blood clots called venous thromboembolisms (VTEs) -- which can travel to the lungs as life-threatening pulmonary embolisms -- have long been known to be a rare but potential side effect of the birth control pill, and for the patch as well. In fact, the FDA had already revised the Ortho Evra label once in 2006, after a study found it doubled women's odds for VTE. Another study found use of the birth control patch boosted women's odds for the clots by about the same amount as did the Pill.

However, an epidemiological study just conducted by the Boston Collaborative Drug Surveillance Program, on behalf of drug maker Johnson & Johnson -- has found the patch may carry an even higher clotting risk than the Pill does. According to the FDA, that study looked at women aged 15 to 44 and "found that users of the birth control patch were at higher risk of developing serious blood clots than women using birth control pills."

The patch does have a checkered past. In November 2006, a group of 43 women sued the product's New Jersey-based maker, Ortho-McNeil Pharmaceutical Co. (a subsidiary of Johnson & Johnson), and San Francisco-based distributor McKesson Corp, alleging that they suffered blood clots and other health woes after being placed on Ortho-Evra.

"This product should not be on the market," Shawn Khorrami, an attorney for the plaintiffs, told the Associated Press at the time. "When you put out a product that gives women more hormones than they need, then you're increasing their risk of developing those ailments."

Similar worries have surfaced in Canada. But Janssen-Ortho, the patch's Canadian distributor, defended the product. "The risk of serious adverse events is small in healthy women, but increases significantly if associated with the presence of other risk factors, such as obesity or smoking," the company said in a statement.

The FDA is also stressing proper use of the Ortho Evra patch. In its statement issued Friday, the agency said it believes the product "is a safe and effective method of contraception when used according to the labeling, which recommends that women with concerns or risk factors for serious blood clots talk with their health-care provider about using Ortho Evra versus other contraceptive options."

Sidney Wolfe, director of the Washington, D.C.-based consumer advocacy group Public Citizen, told Toronto's The Globe and Mail newspaper that women "shouldn't use [the patch]. It shouldn't be used because it's a new product with no unique advantage."

One gynecologist begged to differ, however. "When you look at any estrogen-containing contraceptive product available on the market, whether it's the Pill or the Evra patch or NuvaRing, the vaginal ring, all of them slightly increase the risk of blood clot," Dr. Melissa Mirosh, former fellow of the contraceptive advice, research and education fellowship program at Queen's University in Kingston, Ontario, told the Canadian Press.

More information

There's more on reproductive health at the U.S. Centers for Disease Control and Prevention.

SOURCES: Jan. 18, 2008, U.S. Food and Drug Administration news release; Jan. 8-9, 2008, Canadian Press; Jan. 18, 2008, Associated Press

Copyright © 2008 ScoutNews, LLC. All rights reserved.