800mcg vaginally or sublingual 3-hrly (max x3 within 12 hrs)
Misoprostol is best administered following an initial dose of mifepristone. If misoprostol is used alone, its effectiveness is lower, the abortion process is longer and more painful, and it is associated with higher rate of gastrointestinal side-effects. However, misoprostol, used alone, is still effective in 75-90% of cases. It is therefore widely used in this way where mifepristone is unavailable.
The recommended misoprostol regimen is 800mcg administered vaginally or sublingually, and repeated at intervals no less than 3 hours but no more than 12 hours for up to three doses.
The regimen is 75-90% effective in completing abortion.
Sublingual administration is less effective than vaginal administration unless it is given every 3 hours, but this regimen has high rates of gastrointestinal side effects.
Oral administration is not recommended due to low efficacy.
The above guidance was taken from guidelines published by WHO Safe abortion: technical and policy guidance for health systems. To view the full text as a pdf click here: