Mifepristone dose in the regimen with misoprostol for medical abortion.

Medical abortion with the antiprogesterone mifepristone followed by a prostaglandin is highly effective and widely used. The mifepristone dose registered is a single dose of 600 mg followed by a suitable prostaglandin analogue 36-48 h later. The 600-mg dose was chosen arbitrarily, and later studies have proven one third of this dose to be equally effective when combined with a prostaglandin analogue. This report reviews published data on the efficacy of mifepristone in different doses and demonstrates that there are no differences neither clinically nor in pharmacokinetics if the dose is reduced to 200 mg.