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Paracetamol/Acetaminophen trial for migraine

Clinical bottom line

Paracetamol (acetaminophen) 1000 mg is effective for treating acute migraine.


The review of paracetamol for treating acute migraine had only just been completed when an important large trial reported [1]. It is important because it used IHS criteria for diagnosing migraine, and was large, well-conducted, and has outcome criteria comparable to those used in controlled trials of triptans.

Study

Patients with at least one episode of migraine with at least moderate pain every two months and aged at least 18 years were eligible. They were randomised by computer generated code to 1000 mg of paracetamol or identical placebo. Tablets had to be taken when pain was at least moderate, and rescue medication was to be avoided for at least two hours. Pain was scored between 0.5 and six hours. The main outcome measure was pain reduced to mild or none (headache response) at two hours.

Results

The trial was of high quality and scored 5 of 5 on a quality rating scale. The number randomized who took paracetamol was 147, and 142 took placebo. Migraine was of severe intensity in 40% of patients.

For headache response (pain mild or none) at two hours, the response rate was 58% for paracetamol 1000 mg and 39% for placebo. The number needed to treat was 5.2 (95% confidence interval 3.3 to 13).

For pain free at two hours the response rate was 22% for paracetamol 1000 mg and 11% for placebo. The number needed to treat was 8.9 (95% confidence interval 5.1 to 38).

Rescue medication was taken by 15% of patient with paracetamol, and 32% for those taking placebo. Paracetamol was rated good or excellent by 52% of those taking paracetamol and 28% of those taking placebo. Paracetamol also produced higher rates of patients whose photophobia and phonophobia symptoms were reduced to zero, and more patients whose functional disability was reduced to zero, both at two and six hours.

There was no difference between the groups for adverse event reporting.

Comment

This high quality study indicates that 1000 mg of paracetamol is effective in treating migraine attacks. It confirms results in a Bandolier review .

Reference:

RB Lipton et al. Efficacy and safety of acetaminophen in the treatment of migraine. Archives of Internal Medicine 2000 160: 3486-3492.