FDA to Review If Teva Plan B Contraceptive Works on Heavier Women

U.S. health officials indicate that an investigation has been launched into the effectiveness of the Teva Plan B Emergency Contraceptive Pill, as a French manufacturer of a virtually identical pill issued a statement recently saying that the “morning-after pill” may not work for heavier women.  

HRA Pharma issued a statement November 26, indicating that its Norlevo emergency contraceptive pill is ineffective on women weighing more than 176 pounds. The announcement came after new data suggested problems with the efficacy of levonorgestrel, the active ingredient in both Norlevo and the Teva Plan B.

The FDA announced plans to launch an investigation after reports by European drug regulators, who ordered versions of the pill there to carry new label warnings that alert users that the morning after pill may be less effective on larger women.

FDA officials said they are currently reviewing scientific information, including a 2011 study by researchers at Edinburgh University which led to the concerns in Europe. The agency said it will decide whether the Teva Plan B requires a similar warning as a result of that investigation.

According to HRA officials, their scientists found that the Norlevo lost some effectiveness in women weighing about 165 pounds, and was completely ineffective in women weighing more than 176 pounds. The company made the discovery while looking for data on another subject.

The Plan B One Step and generic versions are sold in the U.S. as an over-the-counter product without age restrictions.

Levonorgestrel is commonly used in numerous older long-term birth control pills and has been considered highly effective in those products for years. It is unclear why it would lose effectiveness in emergency contraception pills.

Morning after pills are used differently from traditional birth control pills, which are taken daily. Instead, they are one-dose pills taken in cases where other forms of contraception, such as condoms, are believed to have failed.