The effect of metoclopramide and prochlorperazine on the absorption of effervescent paracetamol in migraine.

Antiemetics modify gastric emptying, a rate-limiting step in drug absorption. The absorption of effervescent paracetamol in water solution was studied in three groups of 10 female patients during acute migraine attacks. Paracetamol was preceded 30 min earlier by a rectal dose of metoclopramide, prochlorperazine maleate, or placebo. Each patient was retested with paracetamol when headache-free. Migraine attacks delayed slightly the absorption of paracetamol solution. Prior administration of rectal prochlorperazine had a minor delaying effect on paracetamol absorption. The peak concentration, the time to reach the peak, and the area under the time-concentration curve from 0 to 6 h of paracetamol were similar with the three treatments.