Emerging preventative treatments for migraine

Over the last decade new drugs have become available for both acute and preventive migraine treatments. Recent evaluation of botulinum toxin type A and the antiepileptic drug topiramate in the prevention of migraine have shown favourable results as far as efficacy and tolerability is concerned. Angiotensin converting enzyme inhibition or receptor blockade is a new approach to migraine prevention that needs to be further evaluated.

Recent research into the pathophysiology of migraine has demonstrated that migraine is a neurovascular disorder with a central nervous system generator. As a result of these new findings, the direction of migraine management has switched from targetting intracranial vascular tone to attempting to modulate neurotransmitter systems.Emerging treatments for migraine prevention include botulinum toxin type A, the antiepileptic drug topiramate and angiotensin II receptor blockade.Botulinum toxin type A is a well-known potent neurotoxin that has been used for many years for its dose-dependent muscle relaxation effect. It also has an analgesic effect, which is believed to be mediated via inhibition of the release of substance P from trigeminal nerves. Recent clinical trials have evaluated the efficacy of botulinum toxin type-A in the prophylactic treatment of migraine. These trials have shown a significant reduction in both migraine frequency and severity in patients treated with botulinum toxin type-A. Botulinum toxin type-A is safe and well tolerated with virtually no systemic side-effects. It also has a long duration of action (up to 4months), making it particularly appealing to patients who do not comply with daily drug treatments. Topiramate is a structurally unique antiepileptic drug with many possibly mechanisms of action for migraine prevention. Several clinical studies have recently been conducted to assess the efficacy of topiramate in migraine prevention. The studies show a reduction in frequency and severity of migraines, as well as reduced consumption of acute-treatment medications, in the patients treated with topiramate.The most common adverse events associated with topiramate treatment are paresthesias, fatigue, nausea, anorexia and abnormal taste. The cognitive effects that are commonly associated with topiramate when it is used in the treatment of epilepsy, are less of a concern with the lower doses needed for migraine. A common result of topiramate use is weight loss.Angiotensin converting enzyme inhibition or receptor blockade is a new approach to migraine prevention that needs to be further evaluated. At present, the mechanism of action in migraine is unknown. In recent studies, candesartan, a long-acting angiotensin II type 1 receptor antagonist, has been effective in reducing the frequency and severity of migraine. Its adverse effect profile has been similar to that of placebo. (Source: Current Opinion in Neurology 2003, 16:341-345)