When Plan B really isn’t
I don’t usually turn to Twitter for my medical news. Celebrity gossip? Sure. Political updates? You bet. Clinical information relevant to the care of my patients? Not so much.
So I was a wee bit unprepared this morning for this:
Teva makes an estimated $60 million a year on Plan B. How much of that is threatened by this news? http://t.co/bTE1RqVt8E
— NickBaumann (@NickBaumann) November 25, 2013
“What’s this?” thought I. Which immediately changed to “WTF?!??!” and “Yikes!” when I clicked on through.
From Mother Jones:
The European manufacturer of an emergency contraceptive pill identical to Plan B, also known as the morning-after pill, will warn women 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. HRA Pharma, the French manufacturer of the European drug, Norlevo, is changing its packaging information to reflect the weight limits. European pharmaceutical regulators approved the change on November 10, but it has not been previously reported.
Anna Glasier, a professor of obstetrics and gynecology at the University of Edinborough, published research in 2011 showing emergency contraceptive pills that use levonorgestrel are prone to fail in women with a higher body mass index. [emphasis added]
Um… holy crap.
From the abstract to the study linked above:
The risk of pregnancy was more than threefold greater for obese women compared with women with normal body mass index (odds ratio (OR), 3.60; 95% confidence interval (CI), 1.96-6.53; p< .0001), whichever EC was taken. However, for obese women, the risk was greater for those taking levonorgestrel (OR, 4.41; 95% CI, 2.05-9.44, p=.0002) than for UPA users (OR, 2.62; 95% CI, 0.89-7.00; ns)
I don’t subscribe to the journal and I don’t see it as part of Children’s Hospital’s institutional subscriptions, either. I will assume that it was a well-designed and executed study comparing levonorgestrel (the hormone in Plan B, a commonly-used form of emergency contraception [EC], now available without a prescription) with a different, prescription-only form of EC. Regardless of its quality, however, it’s only one study and as such not necessarily something that would make me do a spit-take with my morning coffee.
What’s striking is that the manufacturer’s own review is prompting a change in its labeling and how surprising those weight limits are. As the Mother Jones article notes, the average weight for American women is 166 lbs, and 176 lbs isn’t in the range that would qualify most people as obese.
Even though I’m the adolescent medicine specialist in my practice, I don’t do a lot of contraceptive counseling these days. (Most of our patients seeking that kind of advice opt for one of the female providers in my office.) The last time I attended the annual conference in pediatric and adolescent gynecology sponsored by the medical school where I’m on faculty was a few years ago, before the study out of Scotland was published. I wasn’t aware of its findings, though if I look for them specifically I can find some information out there.
However, I checked with a colleague who did attend the conference when it was held a couple of months ago, and she says there was no mention at all of a link between obesity and lowered EC efficacy rates. And if the weight limit for maximum efficacy is 165 lbs and for any efficacy is 176 lbs, that’s a really big deal! I didn’t expect that preventing pregnancy with EC in a significant number of American women to be just another story medical providers have been telling ourselves.
It is dismaying to consider that such a significant factor in the effectiveness of a medication I’ve dispensed to God knows how many patients was not detected in premarket clinical trials. I’m also a bit confounded that I had to search for information regarding the Contraception study, and that its results weren’t more widely publicized within the medical community. (As a pediatrician, albeit one with specialized interest in that area, it is admittedly quite plausible that I missed information that received more attention in other specialty areas like OB/GYN or family medicine. I do plan to attend that same conference again next year, and will be listening extra hard for mention of this issue.)
If this news is only coming to me through happenstance as of now, I can only imagine that the overwhelming majority of American women who might consider using this medication have no idea how much their weight might be affecting its potential benefit to them. I certainly hope Teva plans to alter its package materials in accordance with its European counterpart, and would politely suggest they go to some additional length to inform women that their medication may not be quite so effective a back-up plan as they once thought.