The Difference Between the Way Men and Women Metabolize Drugs.
This week Brett and I are talking about an article that was just published at the end of January 2013 in the New York Times. This article takes a look at the problems which are being identified by pharmacies and physicians around the idea that there need to be different dosage amounts for medicines taken by men and women. Men metabolize medicines differently than women, in part because of the size differences and in part because of the construction of our bodies. Women have more fat deposits than men do. Many medicines are fat soluable. Medicines rest in the fat tissue of the body until they can be metabolized. Since there are more fat deposits in a woman’s body it may be that women absorb more of a medicine than a man does and that will throw off the predictive values used to determine the proper dose.
One of the reasons that this is now becoming a concern is that until 1993 women of child-bearing age were not allowed to be included in testing programs for developing new drugs and taking them to market. As a result we had drugs come to market that were put into general use. After they were put on the market it was determined that there were problems or adverse effects on women. These drugs were then pulled off the market. A recent government accountability study found that between 1997 and 2000 eight out of ten drugs which were pulled off the market were pulled because of adverse side effects on women. 80% of the pulled drugs were pulled because women were not included in the studies.
We talk about several specific drugs, like Propecia, Androgel, and Flomax to point out the examples and differences. One point that gets made is that there are two doses for Propecia, a five mg dose for men and a one mg dose for women. This is really unusual and progressive. The problem however, is that the one mg dose cost about five times as much as the five mg dose. The best solution seems to be to prescribe the higher dose and then cutting the pill!
We also discussed over the counter medicines and supplements and the reality that the active doses are much less than they are in prescribed medicines.
One last focus of our discussion today is a report that the American Endocrine Society has come out in support of using hormone replacement treatments for women who are exhibiting symptoms due to the loss of hormones. They reinforce the message that the WHI study was incorrectly interpreted and encourage doctors and women to look at hormone replacement as a possible positive strategy.