FDA to Decide Status of Morning-After Pill
Agency Nears Decision on Over-the-Counter Sale of Drug Known as 'Plan B'
WebMD News Archive
How Well Does Plan B Work?
To prevent pregnancy, Plan B should be used as soon as possible after sex. That's why family planners encourage sexually active women who do not want to become pregnant to keep an emergency contraceptive in their medicine chest.
Theoretically, Plan B should work until the fertilized egg is implanted in the womb. It's been tested for up to five days, Plourd says -- but it's strongly recommended that women use it within 72 hours of sex.
If 100 women have sex one time during a single menstrual cycle -- without using any form of contraceptive -- eight of them will get pregnant.
If those same 100 women take Plan B within 72 hours of sex, two of them will become pregnant. That, Plourd says, means it's 75% effective.
"Preventing pregnancy 75% of the time is less than almost every other form of contraception," Plourd says. "That is why it is plan B, not plan A."
How Safe Is Plan B?
Julie A. Johnson, PharmD, chairwoman of the University of Florida department of pharmacy practice, was a member of the 2003 FDA advisory panel that voted to approve Plan B for over-the-counter sale.
"I've been on this committee, the Nonprescription Drug Advisory Committee, for almost four years, and I would take this to be the safest product that we have seen brought before us," Johnson said in a transcript of the panel meetings. Johnson voted with the majority for nonprescription approval.
Few argue that Plan B is unsafe for adult women. But some of the panelists expressed concern that the drug had not been tested in enough teenage girls. And panel chairman Louis R. Cantilena Jr., MD, PhD, worried that tests of Plan B -- designed to mimic actual use of the drug -- did not reflect the way the drug would be used in real-life nonprescription situations.
"My concern [with the Plan B actual-use safety study] is that it doesn't accurately reflect what will likely be the most common setting for this product based on what we've heard," Cantilena said in the transcript. "So the actual use [study] was not as close to possible to what we think will actually happen with the drug." Cantilena voted with the minority to disallow nonprescription sales of Plan B.