Ovulation-inducing drugs: a drug utilization and risk study in the Dutch population

This study describes the use of the ovulation stimulating drugs clomifene, human chorionic gonadotropin (hCG) and human menopausal gonadotropin (hMG) in a representative sample of a population of Dutch women in the child-bearing age group. Clomifene or hMG/hCG are seldom used alone. A considerable percentage of the women received at least four different ovulation-inducing and related drugs during the observation period of two years. Thirty percent of the women who used clomifene were treated for 6 or more cycles. These findings argue for a relative "overuse" and "misuse" of clomifene. Buserelin, a drug not registered for the indication ovulation induction in The Netherlands but used in in vitro fertilization (IVF) programs as inhibitors of pituitary gonadotropin production, was nevertheless prescribed to 38% of the hMG /hCG users and to 11 % of the clomifene users. Our study indicates that, though the potential risks of congenital malformations due to clomifene are difficult to assess, they may be considerable; this, and the fact that different ovulation-inducing drugs are used together with clomifene, emphasizes the need for post-marketing surveillance.