Propranolol for migraine prophylaxis
Clinical bottom line
The amount of information on which to base treatment frequent migraine headaches with propranolol is small, and not consistent.
Reference
K Linde, K Rossnagel. Propranolol for migraine prophylaxis. Cochrane database of Systematic Reviews 2004 issue 2
Background
Propranolol, a beta-blocker, is one of the most commonly prescribed drugs for the prevention of migraine attacks. A previous systematic review in 1991 had limited information, but indicated that propranolol may be helpful in reducing the frequency of migraine attacks.
Methods of the review
- Date review completed: May 2003
- Number of trials included: 58 trials of at least 4 weeks duration, of parallel group or crossover design.
- Number of patients: 5072
- Control groups: Placebo, active comparators
- Main outcomes: Responders (usually at least 50% reduction in the number of migraine attacks, but occasionally at least 50% reduction in headache index or global assessment), headache frequency, adverse events
Results
The number of studies and patients that compared propranolol with placebo with the outcome of responder was small. Only four trials with 205 patients compared propranolol 80-160 mg with placebo (parallel group and first period crossover data), and the results in individual trials can be seen in Figure 1.
Figure 1: Individual trials comparing propranolol 80-160 mg with placebo for at least 50% reduction in migraine
Overall there is a significant increase in the number of responders with propranolol (53% compared with 31% with placebo). The relative benefit is 1.7 (95% confidence interval 1.2 to 2.4), and NNT 4.7 (2.9 to 12). However, as Figure 1 shows, the largest trial from 1996 with over 60% of the total number of patients showed no significant benefit. All the statistical significance comes from small trials from the 1970s with quality scores of 2/5 points, where some residual bias was possible even though the trials were described as randomised and double blind.
There were comparisons with other drugs, but these were mostly small and without any clear indications of difference.
Comment
There remains little evidence that propranolol is of great benefit in reducing migraine attack frequency.