The drug, which is approved for use in treating men with erectile dysfunction, did not appear to help women as well, according to a report presented Tuesday at the American College of Obstetricians and Gynecologists meeting here.

      In a study of 577 women with sexual arousal disorder, half were randomly assigned to take Viagra (sildenafil) and half took an inactive placebo drug. The women took the drug 1 hour before having sex, but no more than once a day, for 12 weeks.

      Three doses--10 mg, 50 mg and 100 mg--of the drug were tested, but placebo was more effective than Viagra at each dose, Dr. Rosemary Basson told Reuters Health in an interview. Basson, of the University of British Columbia in Canada, was lead author of the study.

      Women aged 18 to 55 who had some type of female sexual dysfunction disorder for 6 months or more were enrolled in the study. The study consisted of a 4-week nontreatment run-in period followed by a 12-week treatment period.

      Thirty-one percent of the 143 women taking 50 mg complained of headache and 35% of women taking this dose reported flushing, Basson noted. At 100 mg, the standard dose for men, 33% of women had headache and 38% had flushing. "Among men, headache and flushing is about 14% at this dose," she said. Women, however, "are more likely to get headaches than men," she added.