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.[…]
But American manufacturers do not currently advise American customers of weight limits for levonorgestrel-based emergency contraceptives.
Because the Food and Drug Administration prohibits generic drug manufacturers from changing product information unless the brand name manufacturer makes a change, companies that manufacture generic versions of Plan B One-Step cannot update their packaging information unless Teva Pharmaceutical Industries, the exclusive manufacturer of Plan B One-Step, acts first. […]
The average weight for women in the US over 20 is 166 lbs.
NotMax
Irrelevant. What is the average weight for women of child-bearing age?
cathyx
Can they take 2?
Punchy
As a pharmaceutical chemist, I should understand why weight makes a difference here, but I cannot. We dont see this effect for other meds, such as ibuprofen and vi#gra, etc., so what’s so unique about this progesterone-mimic that makes is so weight sensitive? I’m guessing it has to do with its lipophillicity, and thus its ability to be absorbed by too much adipose tissue before it reaches the target areas….but again, docs dont prescribe regular birth control dosages based on weight, do they?
Punchy
Dammit…stuck in moderation b/c I used the dreaded V-word. Help?
MattR
@NotMax:
Isn’t the more important question – what percent of women of child bearing age weigh more than 176 lbs?
? Martin
Well, can’t wait to see what the GOP distorts this into. No doubt this will be proof that Plan B was designed by liberals exclusively for 12 year old girls in order to destroy America.
Zifnab25
I can’t wait until the factoid pops up in anti-abortion literature. “Plan B is terrible because it murders babies! Also it doesn’t work at all for anybody ever.”
Davis X. Machina
@Zifnab25: And the portions are so small!
TooManyJens
@cathyx: The article says
I don’t have my PubMed-searching fingers on right now, but “not proven to be a solution for this problem” probably just means that the studies haven’t been done, not that they’ve been done and don’t show that higher doses are effective for larger women.
@? Martin:
More likely, it’ll be a conspiracy theory about how the evil birth control pushers deliberately made faulty contraception that gave women a false sense of security about having sex, so that they could make money on the abortions those women get when they get pregnant. (I wish I were kidding, but I’ve seen this one before.)
catclub
@MattR: And what about the airspeed velocity of an unladen swallow?
cathyx
Per CDC:Measured average height, weight, and waist circumference for adults ages 20 years and over
Men:
Height (inches): 69.3
Weight (pounds): 195.5
Waist circumference (inches): 39.7
Women:
Height (inches): 63.8
Weight (pounds): 166.2
Waist circumference (inches): 37.5
EconWatcher
@MattR:
Plus, to say the obvious, an average of a varied population is rarely meaningful. Warren Buffet and I have an average net worth in the billions.
rikyrah
this is a huge deal…didn’t know it at all
ThresherK
@cathyx: Yeah, is this a mg-per-pound thing?
I don’t take a lot of meds, and I haven’t fluctuated weight much after starting any. However…
TooManyJens
@MattR: These data are slightly old (2003-2006), but Table 4 should give you some idea. The median weight for women of reproductive age runs about 8-10 pounds less than the mean.
http://www.cdc.gov/nchs/data/nhsr/nhsr010.pdf
Eyeballing it, I’d say probably around 40% of women of childbearing age are over 176. Or were in 2003-2006.
Mino
Have never heard of a situation like this appears to be. Increased dosage for increased weight is ineffective?
dpm (dread pirate mistermix)
@TooManyJens: Thanks for looking that up.
TooManyJens
@Mino: It’s not increased dosage, though. Plan B is a standard dose. They don’t know whether increased dosage would be effective for increased weight. I imagine somebody will be doing that study soon.
MomSense
This is one time when I am grateful to be below average.
aimai
@Davis X. Machina: Well played.
cathyx
@TooManyJens: But why would weight matter if it didn’t have anything to do with distribution of the drug in the body?
TooManyJens
@TooManyJens: My eyeballs aren’t that good — probably closer to 30%, looking again. Fewer for white women, more for African-American women.
@cathyx: I’m not sure I understand the question.
John D.
http://www.ncbi.nlm.nih.gov/pubmed/21920190 appears to be the ONE STUDY used to make this extraordinary claim. The grain of salt I’d have to ingest to buy this without a lot more research weighs 176 lbs or so.
shortstop
@? Martin: I think we can count on a few gratuitious “No fat chicks!” as well.
Joel
@Punchy: My guess would be that steroid hormones, being lipophilic, can get trapped in fat tissue.
shortstop
@shortstop: (I know how to spell gratuitous. I didn’t get back in time to correct it.)
Three-nineteen
So Plan B One-Step is not sold in the US, only the generic medication is? Because, if this weight limit is true, that would seem to be a huge labeling problem for Teva, and not only in the US. I can’t imagine any of the European regulatory bodies accepting that such a limitation is not in the labeling.
Mnemosyne
@Punchy:
IANAChemist (or medical person of any type), but the way I’ve heard it explained is that women can store estrogen in their fat, which can throw off the dosage. IIRC, the estrogen issue also makes being overweight a risk factor for breast cancer.
I have a friend who learned the hard way that you need a higher dose of oral contraceptives to prevent pregnancy if you’re overweight. Her husband ended up having a vasectomy after their daughter was born.
Joel
@John D.: It’s not really an extraordinary claim. It’s easy to envision a mechanism for why there would be a weight cutoff, and plenty of drugs are dosed according to weight.
TooManyJens
@Three-nineteen: Plan B One-Step is sold in the U.S. Teva’s already been under pressure from advocates to update their product labeling to reflect the current scientific consensus on its mechanism of action (namely, that it doesn’t prevent implantation), so I hope they’ll get that done as well as updating with this new weight information.
John D.
@Joel: It’s an extraordinary claim because *nobody else* has seen this cutoff. There are many studies that indicate that levonorgestrel is ineffective post-fertilization (http://www.ncbi.nlm.nih.gov/pubmed/20399948 and http://www.ncbi.nlm.nih.gov/pubmed/17241840 to name two), but nothing of the sort of weight effect has been seen in any of the other studies to date. THAT makes it extraordinary, and that makes drawing the sweeping (and very oddly specific) claims of the sort made in the MJ article suspicious.
David in NY
Whoa. I weigh 165 lbs. I’m eight inches taller than the average American woman.
srv
I’ll give you three: Chastity, Celibacy, Continence
TooManyJens
@John D.:
I don’t know about the EC studies, but according to this article in Contraception, women over 130% of their ideal body weight have generally been excluded from studies of oral contraceptives. If that’s also true of the EC studies, then of course they wouldn’t have found an effect.
EthylEster
front pager wrote: The average weight for women in the US over 20 is 166 lbs.
Linky?
Doesn’t sound right to me.
TooManyJens
@EthylEster: See the link in #15. Those are older, slightly different numbers, but close.
Capri
@Punchy:
Actually, the doses for adults are not weight-specific because it’s assumed that everyone weighs 170 pounds, It’s not because humans all uniquely get the same effect from a drug despite their weight, lean body mass, percent fat, or anything like that. It’s because adults were enough alike that it’s been assumed that the “average” person is close enough to anyone’s individual weight.
In children and veterinary medicine – where body weights vary a great deal, the vast majority of the exact same drugs are dosed on a mg/kg basis.
Ironically, hormones are a class of drugs that is least weight sensitive. I give a 1600 pound horse 2X the amount of antibiotic that I’d give an 800 pound horse, but they’d both get the same dose of prostaglandin.
Bill in Section 147
@David in NY: So it shouldn’t be a problem for you. Keep using as directed.
Bill in Section 147
@srv: That is a great plan but every conservative fails to be able to implement that as a personal policy.
shortstop
@srv: Bishop Paprocki, is that you?
Joel
@John D.: I’m not very involved in clinical studies, but typically studies are designed around hypothesis-testing. That means you’re looking at results consistent with (or inconsistent with) an existing hypothesis and doing your best to control for everything else. The fact that other studies haven’t identified this risk factor is essentially meaningless unless they were specifically looking for it.
Goblue72
@cathyx: @cathyx: what this tells me is Americans are really fat.
beltane
The average weight for women over the age of 20 is 166 lbs? Really? Thank you for making me feel like a supermodel.
Steve S
That is mind-boggling.
muricafukyea
Then again if you weight that much you probably won’t have that problem very often!
Villago Delenda Est
This is not a problem, really. No woman over 140 lbs ever has sex.
(OK…I’ll go stand quietly in a corner now)
PhoenixRising
@TooManyJens:
Wait, what? Link didn’t work for me, but I’m confounded by the suggestion that the Pill isn’t tested on a representative sample of sizes of womyn but instead on the skinny ones? That seems…what’s the word…incompetent? To the point of actionable?
If true, I’m going to law school so I can rake in 33% of a whole lotta wrongful-life settlements against Ortho.
YellowJournalism
@PhoenixRising: Only skinny chicks get laid. Only svelte, blonde white women in their teen years or twenties are ever at risk of a sexual assault that could result in a pregnancy.
greenergood
@Villago Delenda Est: Sadly, we women over 140 lbs do have sex – we just hate ourselves all the way through it, ’cause that’s what we’ve been told to do. Meanwhile the big guys?? Well they don’t have enough magazines telling them to be skinny, or die lonely. NB: this is not any slur against big guys that have conflicts about their weight, attractiveness etc – it’s just that 98% of magazines are focused on women’s slenderness, abs, ‘thigh gap’ whatever the f that is – and now women of contraception-using age have something else to worry about.Sheesh …
TooManyJens
@PhoenixRising: I don’t know what went wrong with the link. Try this one: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2736633/
From what I can tell, it’s because they want to do the testing on healthy women, and over a certain weight people are considered “unhealthy” by definition. Which is a hell of a vicious circle, since fat people taking drugs that are only tested on thinner people isn’t likely to do wonders for their health.
Fort Geek
@cathyx: I seem to remember that fat cells have an effect on estrogen levels (the Wikipedia entry notes that fat cells produce it (but doesn’t mention amounts, vs. the ovaries’ own supply).
Maybe the additional estro from fat interferes with the Plan B’s effects? (Not an expert…just looking at a possible answer)
Paul in KY
What if the plus-size woman takes 2 of them?
Mr_Gravity
Hidden somewhere in the numbers is the implication that the “average” woman over twenty could curbstomp me into the middle of next week primarily because I haven’t been eating enough pizza.
I’ve got work to do.