FDA Discovers Major Gender Differences in Drug Metabolism

[Gemini]

FDA's Sandra Kweder interviewed on "60 Minutes" Feb 9, 2014 describes why the dose of Ambien has been cut in half for women:

http://www.cbsnews.com/news/sex-matters-drugs-can-affect-sexes-differently/ [20-minute video]

Kweder directed the recent ME/CFS "Voice of the Patient" project. The report does not mention ME/CFS but has broad implications for new clinical trials and research studies across the board.

Sex differences have been found in pain receptors, liver enzymes, & wiring of the brain.

 

[rosie26]

What about the differences in weight as well. ? Should a slimmer person get less than someone that is larger in body weight. ? Or a larger person more than a person with less bodyweight.

 

[adreno]

What about the differences in weight as well. ? Should a slimmer person get less than someone that is larger in body weight. ? Or a larger person more than a person with less bodyweight.

That would make sense, but sex probably accounts for a higher degree of differences.

 

[rosie26]

It's always concerned me a bit @adreno as I am on the slimmer side and I think the smaller body weight takes a bigger hit with some of these powerful drugs. I don't tolerate tablets at all except for antibiotic's, which I seem to be okay on.

But 2 years ago I had what looked like a toenail fungal infection, so I felt I had to go on Terbinafine which is very hard on the liver. I noticed the dose I was on was the same for everybody!. I felt ill about about a week into it and ended up having to stop it. It could be too hard to adjust for bodyweight, I don't know.

 

[Little Bluestem]

Age can make a difference, too. Nonetheless, I think we should be very proud of the FDA for figuring out the difference between girls and boys.

 

[alex3619]

It has long been recognized that a huge hole in much of the drug research was that it was done on healthy adult caucasian males initially, then sick males unless it was a female disorder. For statistical reasons a homogeneous group means its more powerful to do a study with just one sex, or one narrow type of patient. Similar problems occurred with children's drugs.

What they buy with that is also reduced generalizability of the results. At least, that should be the case, but it seems to frequently be ignored.

Many drugs are based on dosage per weight. However standardization, such as tablets at fixed dosages, or pre-loaded syringes, fail to enable proper drug titration.

Its for similar reasons that many CFS and ME studies are on women. You can get a much better statistical power, therefore a smaller and cheaper study, by using only one sex. The results are then often presumed to apply to men, and teenagers. There is always danger in doing that. Similarly most CFS or ME studies are on mild and moderate patients, not the severe. If using weak definitions such as the Oxford definition, then there is potentially huge patient diversity. Something that applies to a mild CFS female patient in her mid-30s, might not apply to a young male teenager with severe ME. Yet the problem is usually lack of funding. How do they get the most research for the least cost? That is the question that plagues our researchers.

 

[peggy-sue]

Initially, women were not used in drug trials because they had "complicated things" such as the reproductive hormone cycle going on which was difficult to control for.
It has been known for some time that men and women respond differently to morphine, and that adrenalin is experienced as anger in men, but anxiety in women.

 

[WillowJ]

I have read articles on this before, actually. In some medicines women seem to need higher doses (e.g. pain medicine, which isn't prescribed readily to women anyway), so it's kind of dangerous to assume lowering the dose is always the right thing to do. Sometimes it is, sometimes it isn't. But it sounds like they will be studying that, so this is good.

It's very good that FDA has noticed people differ from one another and we cannot generalize from one group to another. I hope they keep up noticing more groups are different.

 

[MeSci]

Maybe one day UK doctors will also realise that normal urine output is linked to body mass. I spent years trying to explain this to doctors from GPs up to consultant endocrinologist who all refused to believe that I had polyuria. I provided them with links to support my argument but they just ignored them. So I gave up.

I knew that blood volume was related to BMI because I was rejected as a blood donor several times on the grounds that they had to take a standard amount, and that this was too much for someone weighing less than 50 kg. This abstract confirms the relationship between (lean) body mass and body fluid volume.

Normal urine flow is proportional to blood volume because the kidneys produce urine by filtering the blood.

Yet UK doctors appear to think that a 50kg person should produce the same amount of urine as someone weighing 100kg!

 

[peggy-sue]

Maybe one day they'll retake their arithmatic "O" -levels...