Morning-after pill ineffective for heavier women, says European maker

A European manufacturer of an emergency contraceptive drug identical to Plan-B, more commonly known as the morning-after pill, will soon issue warnings on packaging sold in Europe after research found that the drug loses its effectiveness in women who weigh more than 165 pounds, according to a Mother Jones report published Monday.

The findings could have serious implications for American women who use emergency contraceptives. On average, women in the U.S. weigh 166 pounds, according to the Centers for Disease Control and Prevention. More than two in three Americans women are overweight or obese, according to the National Institutes of Health.

Sold under the name Norlevo, the emergency contraceptive contains a compound called levonorgestrel to prevent pregnancies. Clinical data from 2011 revealed that pills containing levonorgestrel are likely to fail in women with a higher body mass index, according to Mother Jones. 

Specifically, the research showed that the drug is completely ineffective for women who weigh more than 176 pounds, and begins to lose effectiveness in women who weigh more than 165 pounds.

The U.S. Food and Drug Administration (FDA) responded to the report late Monday.

The FDA is "currently reviewing the available and related scientific information on this issue, including the publication upon which the Norlevo labeling change was based," FDA spokeswoman Erica Jefferson told Reuters Monday via an email. "The agency will then determine what, if any, labeling changes to approved emergency contraceptives are warranted."

HRA Pharma, the French manufacturer of the drug, requested permission from a European Union governing body to update its product information after reviewing the data.

A new packaging slip with the weight warning will appear in boxes of Norlevo sold in Europe in the first half of 2014, reported Mother Jones.

About 6 million American women used emergency contraceptive pills from 2006 to 2010, according to a CDC survey published in February.

American manufacturers of levonorgestrel-based emergency contraceptives do not currently advise American women of a weight limit.

The FDA prohibits generic drug manufacturers in the U.S. from making any changes to their products unless the brand drug manufacturer makes the change first. Generic manufacturers of Plan B One-Step are thus prevented from issuing a weight warning unless Teva Pharmaceutical Industries, the manufacturer of Plan B, takes action first.

Earlier this month, the FDA proposed a rule change that would allow generic drug makers to update product labeling independently of the brand drug manufacturer.

Emergency contraceptive pills sold in the U.S. include Plan B One-Step, My Way and Next Choice One Dose. Plan B is the only brand sold in the U.S. that is available to women of all ages without a prescription.

The pills are up to 89 percent effective when taken within 72 hours after unprotected sex, according to Planned Parenthood’s website, making them the most effective morning-after pills available without a prescription.

They continue to reduce the risk of pregnancy up to five days after unprotected sex, but become less effective as time passes.

It is not known whether drugmakers can produce an effective levonorgestrel pill for women who weigh more than 165 pounds. Karina Gajek, a spokeswoman for HRA Pharma, told Mother Jones that increasing the dose was not shown to resolve the problem. She recommended that women with higher weight discuss “alternative emergency contraceptive options with their physician: IUD or alternative oral emergency contraceptive."

Amel Ahmed contributed to this report.