Misoprostol dosage is affected by factors such as the desired effect of the drug, the stage of pregnancy a woman is in and the method of administration of the drug. For example, for inducing labor in a patient, 50 micrograms (mg) should be given every four hours if taken orally, or 25 mg should be administered vaginally every six hours. For patients with an incomplete abortion within four to 12 weeks, 600 mg should be taken orally, once only. The recommended misoprostol dosage changes depending on circumstances such as these.
Misoprostol is classified as part of a hormone group called prostaglandins. The efficiency of the drug form of this hormone is dependent upon the amount of receptors the woman taking the medicine has. This can be generally determined by the stage of pregnancy, and the misoprostol dosage is partially based on this. In early pregnancy, the woman has fewer prostaglandin receptors and therefore needs a larger dose of the drug. In the later stages of pregnancy, there are more receptors and therefore less of the drug is required. Generally, misoprostol comes in 200 mg tablets, but can also be found in 100 mg tablets or 25 mg pessaries for vaginal administration.
The drug can be administered in a variety of different ways, and the recommended misoprostol dosage differs depending on these routes of administration. The drug can be administered orally, vaginally, rectally or sublingually, which means under the tongue. Generally, vaginal doses are more efficient than oral doses, but can only be given for certain conditions. Rectal administration generally requires a larger misoprostol dosage than when administered orally or sublingually.
When being used for induction of labor in patients over 24 weeks pregnant, the recommended misoprostol dosage is either 25 mg administered vaginally every six hours or 50 mg administered orally every four hours. If the drug is being used to aid cervical ripening and dilation, 400 mg of the drug should be administered vaginally three hours before the procedure. If the drug is being used for a missed abortion between the fourth and 12th week of pregnancy, 800 mg should be administered vaginally or sublingually.
The recommended misoprostol dosage largely changes based on these factors, but the dosage is generally determined as a result of the desired effect of the drug. For example, when misoprostol is being used to treat a postpartum hemorrhage, the recommended dosage is either 1,000 mg rectally, 200 mg orally, or 400 mg sublingually. The drug should only be taken under the supervision and direction of a medical professional.