Micronized progesterone: clinical indications and comparison with current treatments

Objective: To integrate and evaluate the pharmacokinetic, endocrine, and cl inical effects of micronized progesterone formulations. Design: Published articles concerning the pharmacokinetics of orally admini stered progesterone and the potential clinical uses of oral micronized prog esterone were reviewed. Results concerning their use for secondary amenorrh ea, premenopausal bleeding disorders, luteal phase dysfunction, termination of premature labor, hormone replacement therapy, and premenopausal syndrom e are summarized. Critical issues to be resolved through ongoing preclinica l and clinical research are highlighted. Result(s): Because of the enhanced bioavailability of oral micronized proge sterone, the compound may be useful for a variety of therapeutic indication s. Oral micronized progesterone is available in France, and a formulation r ecently has been approved in the United States for the treatment of seconda ry amenorrhea and postmenopausal hormone replacement therapy. A large body of evidence, including the Postmenopausal Estrogen/Progestin Interventions study, suggests that the use of a combination of estrogen and oral microniz ed progesterone is optimal for long-term hormone replacement therapy. There also are data indicating that oral micronized progesterone could be of pot ential use fbr the treatment of premenopausal bleeding disorders, luteal ph ase disorders, and premature labor. Conclusion(s): Oral micronized progesterone has widespread clinical potenti al, particularly for the treatment of secondary amenorrhea and dysfunctiona l premenopausal bleeding, and as a component of postmenopausal hormone repl acement therapy. (Fertil Sterile 1999;72:389-97. (C) 1999 by American Socie ty for Reproductive Medicine.)