Paracetamol migraine

Vomiting and diarrhea from any cause will obviously alter the likelihood of any medication being absorbed. In migraine even before the attack is fully developed and before vomiting has occurred, gastric stasis exists. Taking a prophylactic dose of aspirin or paracetamol is unlikely to be effective if it does not pass the pylorus. Suppository forms of e.g., ergota-mine, have been developed to permit self medication early in the attack. 

Migraine can often be treated with paracetamol, ibuprofen or aspirin alone, or with combination products containing them. There are also some non-prescription medicines specifically licensed for the treatment of migraine. One such is a coformulation of paracetamol, codeine and the antihistamine buclizine, included for its antiemetic action. Other specific migraine treatments are reviewed below. 

Isometheptene is a sympathomimetic, used in the treatment of migraine and throbbing headache for its vasoconstrictor effect. It is combined with paracetamol in one proprietary product. 

Intravenous metoclopramide 10 mg increased the peak plasma levels of a single 1.5-g dose of paracetamol by 64% in 5 healthy subjects (slow absorbers of paracetamol), and increased its rate of absorption (peak levels reached in 48 minutes instead of 120 minutes), but the total amount absorbed remained virtually unaltered. Oral metoclopramide also increases the rate of paracetamol absorption, probably because the rate of gastric emptying is increased. Similarly, the speed of absorption of paracetamol may also be increased by domperidone. This interaction is exploited in Paramax (a proprietary oral preparation containing both paracetamol and metoclopramide) to increase the effectiveness and onset of analgesia for the treatment of migraine. This is obviously an advantageous interaction in this situation. 

Seaber EJ, Ridout G, Layton G, Posner J, Peck RW. The novel anti-migraine zolmitriptan (Zomig 311C90) has no clinically significant interactions with paracetamol or metoclopramide. EurJ Clin Pharmacol (1997) 53,229-34. 

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