January 11, 2005

Depo-Provera and Bone Loss

Women's health groups say "I told you so"

by Lisa Nussey

The Dominion - http://www.dominionpaper.ca

On November 18, Pfizer Canada Inc. released a safety update on their long acting, injectable contraceptive Depo-Provera (medroxyprogesterone acetate), citing ongoing research that points to significant Bone Mineral Density (BMD) loss amongst its users. Pfizer warns health care professionals that "bone loss is greater with increasing duration and may not be completely reversible. It is unknown if the use of Depo-Provera during adolescence or early adulthood, a critical period for bone accretion, will reduce peak bone mass and increase the risk of osteoporotic fracture in later life."

Women's health groups say that the findings come as no surprise. For decades, activists have challenged the manufacturers and drug regulating bodies regarding both the political and health implications of the drug that is disproportionately prescribed to marginalized women at home and abroad.

Depo-Provera was first approved in the US in 1960 as a treatment for endometriosis and endometrial carcinoma. Despite persistent lobbying from Pharmacia and Upjohn, the original manufacturers of the drug before it was acquired in 2003 by Pfizer, the FDA would not approve it as a method of birth control in the US, citing doubts about long term effects and potential connections to cancer.

While Pharmacia lobbied for approval in the US, Canada and Europe, the drug was being exported to poor countries as part of a global population control strategy, despite the opposition from health groups in most of the affected countries. The export of Depo-Provera is often discussed in the same vein as the infamous Dalkon Shield IUD, banned in the US for its abysmal safety record, but continually sold to the underdeveloped world at a 48% discount.

In 1985, Pharmacia and Upjohn again challenged the FDA for approval, without success. At the same time women's and community health groups across the country formed the Canadian Coalition on Depo-Provera- an umbrella group of over 80 Canadian organizations. They lobbied not to have the drug approved for contraceptive use in this country because of their concerns about what was yet unknown about Depo-Provera and about the social misuse of the drug that had already been witnessed.

In addition, they demanded the creation of a registry of Depo users, both for purposes of tracking long-term effects and to ensure that if problems with the drug were discovered the women could be easily contacted. This registry was never created. They were successful in their request for a set of nation-wide hearings to be made available to women with experience with the drug, which took place in 1986. Following these hearings, Health Canada again denied approval of the drug.

Finally, in 1992 the drug was approved in the US, and then in 1997 in Canada. Consistent with current Health Canada policy, the data from the trials on which these approvals were made was never made available to the public.

Information that has been made available by the drug companies says that a woman needs to be extremely healthy in order for her body to cope with persistent levels of synthetic progesterone. A detailed history and physical exam is suggested before prescription, with periodic reevaluations throughout the course of use.

According to many critics, Depo-Provera is targeted at women on the margins of North American society, women who have inadequate access to health care and who usually suffer disproportionately from poor health.

Women in Canada have long been outspoken about the effects of Depo-Provera. In their 1991 letter to then federal Health and Welfare minister Benoit Bouchard, the Canadian Coalition on Depo-Provera pointed to a growing body of research connecting Depo use to breast cancer and osteoporosis. In addition, they cautioned about the side effects reported by women which include irregular or no menstrual periods, weight gain, decreased libido and depression.

In response to Pfizer's announcement, the Canadian Women's Health Network (CWHN), pointing to the history of the drug's approval, said that "women's health groups can be a far more reliable and informed source than either the drug companies or Health Canada." Madeline Boscoe, executive director of the CWHN and co-founder of the Canadian Coalition on Depo-Provera says that "my frustration is that they didn't listen to us and now our worries have come true."

According to groups like the CWHN, the history of women's medicine is characterized by such a silencing of women. In what they call repeated cases of experimentation without consent, such as Depo-Provera or last year's hormone replacement therapy revelations, women are consistently reassured that the pharmaceuticals they are using are safe, only to learn after the fact that their therapies are potentially doing more harm than good.