Medical Moment: Lower Dose Drugs for Women?

29 Aug Medical Moment: Lower Dose Drugs for Women?

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Dr. Heather Linder answers this week’s question: Should women be taking lower drug doses than men?

Dr. Heather Linder

For over 20 years women have been accidentally overdosing on Ambien.

Ambien (zolpidem) is the most popular sleep aid in the country, with over 40 million prescriptions annually.

After driving simulation studies, the FDA has lowered the recommended dose of Ambien for women.

Since women take longer to metabolize Ambien, they consequently have more of the drug remaining in their bloodstream in the morning. In fact, women may have up to 45% higher levels of Ambien in the bloodstream compared to men.

Eight hours after taking Ambien, approximately 10-15% of women will have a level of the active ingredient in their bloodstream that could impair driving, compared to 3% of men.

Therefore, the recommended dosages  for women have been cut in half from 10mg to 5mg for the immediate-release forms of Ambien and from 12.5mg to 6.25 mg for the extended release forms (Ambien CR).  In addition to the changes, the FDA is now requesting driving data on all sleep medications.  

Although Ambien is the only medication with different dosages for men and women, it may just be the tip of the iceberg. When it comes to medicine, men and women may be much more different than we once thought.

According to Dr. Janine Clayton, director for the Office of Research on Women’s Health at the National Institutes of Health, “there are a lot of sex differences for a lot of drugs, some of which are well known and some that are not well recognized.”

Until 1993, women of childbearing age were excluded from clinical trials and drugs were primarily tested on men. Therefore, we did not know the effects of many medications on women until the medications reached the market. Because of this, women may experience more adverse effects from medications.

Studies show that women are 50-75% more likely to have an adverse drug reaction compared to men. In fact, 8 out of 10 of the drugs removed from the market between 1997 and 2000 posed greater health risks to women as compared to men.

Researchers are still trying to understand why women metabolize drugs differently than men. Women tend to weigh less and have a greater percentage of body fat. Drugs that are attracted to fat cells tend to remain in females longer than males.

Women also may differ in how drugs are absorbed through the gastrointestinal system or how their liver and kidneys metabolize drugs.

Hormones also play a key role, especially estrogen. Oral contraceptives and post menopausal hormone replacements further complicate the picture and women may metabolize drugs differently at different times in their menstrual cycle.

Other examples of gender differences in drugs include the following:

• Aspirin is better at preventing heart attacks in men and strokes in women

• Opioid pain medication tends to work better in women compared to men

• Women may respond better to beta blockers than men

• Lotronex (alosetron) that is used to treat irritable bowel is only approved for women since it was found to be ineffective in men

• Giazo (balsalazide) that is used to treat ulcerative colitis in males was found to be ineffective in females

This may just be the beginning of what researchers are learning about the gender differences within medicine.

This Medical Moment was sponsored in part by Telluride Properties and through the generosity of an anonymous local supporter committed to a healthy Telluride and the future regional medical center.

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