Effects of prostaglandin E2 and F2alpha therapy.

Prostaglandins are widely distributed in the nervous system and have important effects on nerve cells. Prostaglandins of the E series tend to cause sedation, whereas this action is much less obvious with F prostaglandins. Prostaglandin therapy for termination of pregnancy is usually administered by the intrauterine route, which means that only very low concentrations of prostaglandin E2 or prostaglandin F2alpha reach the cerebral circulation after passage through the highly effecient metabolizing system in the lungs. The blood-brain barrier may also reduce the amount of prostaglandin reaching the nerve cells.However, prostaglandin F2alpha appears to have been responsible for major convulsions in a small proportion of patients, and the appearance of epileptiform spike activity has been clearly demonstrated in some patients with normal pretreatment EEGs. Prostaglandin E2 has not been reported to cause convulsions or epileptiform spike activity in normal women, although deterioration of an already abnormal EEG has been seen in one patient. Although the risk of convulsions with prostaglandin F2alpha is low, it seems preferable to use prostalgandins E2 where possible, particularly on patients with a history of epilepsy.