The latest class of fertility pills are aromatase inhibitors, drugs which temporarily prevent the body from making estrogen. In a fashion not too different from clomiphene, aromatase inhibitors initiate the release of FSH which stimulates the growth of follicles. At Main Line Fertility we use the aromatase inhibitor named letrozole (Femara).
Letrozole appears to be slightly less reliable than clomiphene for inducing ovulation. On the other hand, its advantages include less drying -up of cervical mucus, thicker development of the lining of the uterus, and a far lower chance of multiple gestation. As is the case with tamoxifen, metformin and rosiglitazone, letrozole is not certified for use as a fertility drug by the FDA (government). Doctors are free to use these drugs for off-label indications at their discretion.
Occasionally, we employ a drug called tamoxifen as an alternative to clomiphene. This medication works through the same mechanisms as clomiphene. It is not FDA approved for use as a fertility drug, but may be used for this "off-label" indication at the discretion of the physician.
Another popular "off-label" drug usage involves medications normally prescribed to non-insulin requiring diabetics. Metformin (Glucophage), pioglitazone (Actos) and rosiglitazone (Avandia) are examples of medications that lower a woman's insulin levels. Lowering insulin levels improves ovulation in some women with the condition known as polycystic ovarian syndrome (PCO).
Common side effects of metformin include gas and intestinal upset. Serious side effects are extremely rare. Rosiglitazone and pioglitazone have fewer common/minor side effects, but require blood test monitoring to detect liver problems. The incidence of miscarriage and, perhaps, birth defects may be reduced in PCO patients who take insulin lowering drugs.
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Letrozole and Other Drugs