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  5. Plan B One-Step (1.5 mg levonorgestrel) Information
  1. Postmarket Drug Safety Information for Patients and Providers

Plan B One-Step (1.5 mg levonorgestrel) Information

Plan B One-Step is an emergency contraceptive, a backup method of birth control. Emergency contraception is used to reduce the chance of pregnancy after unprotected sex (if other birth control failed or was not used). It is not for routine contraceptive use. Plan B One-Step is available as a nonprescription (over-the-counter or OTC) drug.

A brief history of Plan B and Plan B One-Step is as follows:

  • On July 28, 1999, FDA approved a new drug application (NDA) for the original product, Plan B, for prescription use.
  • On August 24, 2006, FDA approved a supplemental NDA permitting nonprescription availability of Plan B for women 18 years and older and by prescription for women 17 years and younger.
  • On July 10, 2009, FDA approved a supplemental NDA permitting nonprescription availability of Plan B for women 17 years and older and by prescription for women 16 years and younger. Plan B has been discontinued and is no longer being marketed.
  • On July 10, 2009, FDA also approved Plan B One-Step (PBOS) (levonorgestrel) tablet, 1.5 mg as a nonprescription product for women ages 17 and older, and as a prescription-only product for women ages 16 and below. Plan B used a two-dose regimen with 0.75 mg of levonorgestrel in each tablet to be taken 12 hours apart, while PBOS is a single dose tablet that contains 1.5 mg of levonorgestrel.
  • On June 20, 2013, FDA approved PBOS for nonprescription use without age restrictions.

Q. What is emergency contraception?
A. Emergency contraception is a method of preventing pregnancy to be used after another contraceptive fails or after unprotected sex. It is not for routine contraceptive use. Drugs used for this purpose are called emergency contraceptive pills, post-coital pills, or morning-after pills. Emergency contraceptives contain hormonally active drugs.

Q. What is Plan B One-Step?
A. Plan B One-Step is an emergency contraceptive, a backup method to other birth control. It is in the form of one levonorgestrel pill (1.5 mg) that is taken by mouth after unprotected sex or contraceptive failure. Levonorgestrel is a synthetic hormone used in birth control pills for over 35 years. Plan B One-Step is available as a nonprescription (over-the-counter or OTC) drug.

Q. How does Plan B One-Step work?
A. Plan B One-Step works before release of an egg from the ovary. As a result, Plan B One-Step usually stops or delays the release of an egg from the ovary. It is one tablet that contains a higher dose of levonorgestrel than birth control pills and works in a similar way to prevent pregnancy.

Q. Is Plan B One-Step effective?
A. The most important factor affecting how well emergency contraception works is how quickly it is taken after unprotected sex or contraceptive failure. Therefore, FDA recommends that all people using levonorgestrel emergency contraceptives follow the product directions exactly and take the product as soon as possible within 72 hours after unprotected sex or contraceptive failure.

FDA recommends that consumers talk to their health care provider about emergency contraception in advance of needing it and understand the importance of using these products as intended.

Consumers and health care professionals are encouraged to report adverse reactions from the use of Plan B One-Step to the FDA’s MedWatch Adverse Event Reporting program at www.fda.gov/MedWatch or by calling 1-800-FDA-1088.

Q. Is Plan B One-Step an abortifacient (causing abortion)?
A. No. Plan B One-Step will not work if a person is already pregnant, meaning it will not affect an existing pregnancy. Plan B One-Step prevents pregnancy by acting on ovulation, which occurs well before implantation. Evidence does not support that the drug affects implantation or maintenance of a pregnancy after implantation, therefore it does not terminate a pregnancy.

Q. Why was the mechanism of action modified on the Drug Facts label and Consumer Information Leaflet in 2022?
A. The applicant for Plan B One-Step submitted a supplemental new drug application (labeling supplement), as amended, to FDA requesting approval to modify some the mechanism of action information on the Drug Facts label and in the Consumer Information Leaflet.

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 mechanism of action in the Consumer Information Leaflet was updated so it is now consistent with the best available scientific evidence.

Q. Why was the mechanism of action in the Drug Facts label changed to remove wording about fertilization and implantation?
A. In response to the submission of the applicant’s labeling supplement, as amended, FDA reviewed currently available scientific evidence regarding the mechanism of action for Plan B One-Step. FDA determined the current science supports a conclusion that Plan B One-Step works by inhibiting or delaying ovulation and the midcycle hormonal changes. The evidence also supports the conclusion that there is no direct effect on fertilization or implantation. FDA also determined that the most appropriate placement of mechanism of action information was primarily in the Consumer Information Leaflet rather than in the Drug Facts label. Accordingly, FDA removed information directly related to the mechanism of action from the “Other Information” section of the Drug Facts label and updated the mechanism of action information in the Consumer Information Leaflet to be consistent with the best available evidence.

The mechanism of action is rarely included in nonprescription drug labeling (and, more specifically, the Drug Facts label) and is not required under FDA’s regulations for nonprescription labeling, as this information is not needed for the safe and effective use of nonprescription drugs in general. Because consumers may be interested in how Plan B One-Step works, information on the mechanism was kept in the Consumer Information Leaflet and updated to be consistent with the best available evidence. Also, both the Drug Facts label and Consumer Information Leaflet retain statements that are consistent with the mechanism of action—that the product will not work if the woman is already pregnant.

Q. Why was the mechanism of action in the Consumer Information Leaflet changed to modify wording about fertilization and implantation?
A. In response to the submission of the applicant’s labeling supplement, as amended, FDA reviewed currently available scientific evidence regarding the mechanism of action for Plan B One-Step. FDA determined the current science supports a conclusion that Plan B One-Step works by inhibiting or delaying ovulation and the midcycle hormonal changes. The evidence also supports the conclusion that there is no direct effect on postovulatory processes, such as fertilization or implantation. Accordingly, FDA updated the mechanism of action information in the Consumer Information Leaflet, which included removing references to the mechanisms not supported by the best available scientific evidence (that is, effects on fertilization and implantation).

Additional information on FDA’s scientific review is available in the decisional memorandum.

Q. Is there information about the mechanism of action that remains on the Plan B One-Step Drug Facts label and the Consumer Information Leaflet that helps inform consumers?
A. The Consumer Information Leaflet includes updated information on the mechanism of action to explain that Plan B One-Step works before release of an egg from the ovary. As a result, Plan B One-Step usually stops or delays the release of an egg from the ovary.

The Drug Facts label and Consumer Information Leaflet continue to include information that relates to when in the reproductive cycle Plan B One-Step works.

Specifically, the Drug Facts label retains the following statement in the “Warnings” section, under “Do not use”: “Do not use if you are already pregnant (because it will not work).”

In the Consumer Information Leaflet, the following statements are retained:

  • Under the heading “What Plan B One-Step is not,” the following statement will remain: “Plan B One-Step will not work if you are already pregnant and will not affect an existing pregnancy.”
  • Under the heading “When not to use Plan B One-Step,” the following statement will remain: “Plan B One-Step should not be used if you are already pregnant, because it will not work.”

These statements are consistent with the mechanism of action described in the Consumer Information Leaflet and remind the consumer that Plan B One-Step does not work when a woman is already pregnant. Therefore, when considering when in the reproductive cycle that Plan B One-Step might work, it will be clear to the consumer that Plan B One-Step works very early in the reproductive cycle (prior to ovulation).

Q. Are there generics of Plan B One-Step and will the labeling for these generics be updated to reflect the same labeling changes for Plan B One-Step?
A. There are multiple (11) generics of Plan B One-Step with an active marketing status. The generics for Plan B One-Step are approved for nonprescription use without age restrictions. A generic drug is required to have the same labeling as the reference listed drug except for certain permissible differences, and generic drug holders are expected to update their labeling after FDA has approved relevant changes to the labeling for the corresponding reference listed drug. Accordingly, the generics for Plan B One-Step are expected to update their labeling to reflect the changes made to the Plan B One-Step labeling by submitting their revised labeling as soon as possible.

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