Comparing two drugs used for ovarian stimulation: clomiphene citrate and tamoxifen.

This study compared pregnancy outcomes in patients who received one of two ovulation stimulating drugs – tamoxifen or clomiphene citrate.

Treatment for female infertility usually begins with drugs that stimulate ovulation. By producing more eggs, there is a higher likelihood of a successful pregnancy. A class of drugs used for ovarian stimulation is called SERMs (selective estrogen receptor modulators). Of these, one drug commonly used to induce ovulation is called clomiphene citrate. Another SERM called tamoxifen, is not approved by the FDA for this indication, and is used off-label. Tamoxifen is also used in the treatment of breast cancer.

Researchers analyzed data derived from 4 large trials comparing tamoxifen to clomiphene citrate as ovulation stimulators. Results showed that there was no statistical difference between the two drugs in inducing ovulation. Similarly, there was no difference between the drugs with regard to achieving pregnancy. Of the four trials included in the analysis, only one had compared the rates of successful births and found no significant differences between the two drugs.

Tamoxifen and clomiphene citrate seemed to be equally effective in inducing ovulation and achieving a successful pregnancy.

Due to the vast experience of using tamoxifen in breast cancer, its side effects are better understood. However, until FDA approval many doctors may choose not to prescribe this drug and instead opt for clomiphene citrate. Moreover, the safety profile of tamoxifen as an ovarian stimulating drug (i.e. it's effect on the rates of live births, and birth defects) is not well studied.

You should ask your doctor whether tamoxifen or clomiphene citrate is better for you.