Drug concentrations higher in women

A study presented at the National Conference on Women and HIV in Pasadena, CA, showed that the drug combination of delavirdine (Rescriptor) and zidovudine (AZT) resulted in a drug trough concentration 1.8 times higher in women than in men.

Although the clinical significance of higher drug trough concentration is unknown, the study, which included 139 women, demonstrates gender differences in AIDS treatment.

"There are several possibilities for higher levels of Rescriptor in the blood of female patients," said study presenter Lynne Wathen, PhD, a clinical monitor for its manufacturer, Pharmica & Upjohn. "Women tend to have smaller body size so they have higher dose per kilogram ratio than men. They may also have altered metabolism at various phases of the menstrual cycle or there may be gender differences in drug clearance."

Despite the different concentrations, the efficacy of the drug combination was the same in male and female patients.