Single-dose letrozole equal to multiple-dose regimen in IUI.(Gynecology)

PHILADELPHIA -- Patients with unexplained infertility who undergo ovarian stimulation before intrauterine insemination have comparable pregnancy rates and side effects when treated with a single 25-mg dose of letrozole, compared with five daily doses of 5 mg each, Marinko M. Bijan, M.D., reported.

"A single dose may be more practical and convenient for patients," commented Dr. Biljan, medical director of the Montreal Fertility Centre, who reported his findings during the annual meeting of the American Society for Reproductive Medicine.

Letrozole, an aromatase inhibitor, was originally used for ovarian stimulation in infertility patients who responded poorly to clomiphene citrate or gonadotropin stimulation.

Dr. Biljan's previous work in this area has shown that, even in good responders to gonadotropins, letrozole used in combination with gonadotropins can reduce gonadotropin requirements by up to 50%.

Letrozole is considered by some specialists to be as effective as and possibly even superior to clomiphene for most patients undergoing intrauterine insemination (IUI).

But the traditional 5-mg dose starting at day 3 of the menstrual cycle and given through day 7 is often impractical, said Dr. Biljan, who now has experience with approximately 2,000 letrozole cycles.

"Patients would call us up and say they forgot their dose yesterday and [ask] should they take two doses today? It was becoming a problem," he said.