FDA updates emergency contraceptive consumer label to specify mechanism of action

The FDA has updated the consumer information leaflet for levonorgestrel 1.5 mg, or Plan B One-Step, to specify that this medication is not an abortifacient and will not affect an existing pregnancy.

Plan B One-Step is a 1.5 mg levonorgestrel (Odyssea Pharma) pill taken by mouth following unprotected sex or contraceptive failure. It is available as a nonprescription over-the-counter drug. The medication works by stopping or delaying the release of an egg from the ovary to prevent pregnancy. Currently, the FDA recommends using Plan B One-Step within 72 hours following unprotected sex or contraceptive failure for it to be most effective.

After reviewing currently available scientific evidence on the mechanism of action for Plan B One-Step, the FDA has determined that this drug inhibits or delays ovulation and the midcycle hormonal changes and does not directly affect fertilization or implantation. The FDA has updated the mechanism of action information to best relay available evidence.

This label change specifies that Plan B One-Step will not be effective if the person taking it is already pregnant and, therefore, will not affect an existing pregnancy. This pill prevents pregnancy before its occurrence, and evidence does not support that the drug impacts implantation or pregnancy maintenance following implantation and is not an abortifacient.

“Based on careful consideration of the applicant’s labeling supplement, as amended, and additional scientific evidence, FDA determined that the labeling for Plan B One-Step should be updated to have the mechanism of action information be primarily in the Consumer Information Leaflet,” the FDA wrote. “The mechanism of action in the Consumer Information Leaflet was updated so it is now consistent with the best available scientific evidence.”