ROLE OF ACE INHIBITORS & AT-II RECEPTOR ANTAGONISTS IN MIGRAINE PROPHYLAXIS : AN OVERVIEW
Migraine is a chronic neurological disorder characterized by recurrent moderate to severe headaches, associated with a number of autonomic nervous system symptoms. Migraine constitutes 16% of primary headaches affecting 10-20% of general population according to International Headache Society. Typically the headache is unilateral (affecting one half of the head) and pulsating in nature, lasting from 2 to 72 hours. Associated symptoms may include nausea, vomiting, photophobia, phonophobia and the pain is generally aggravated by physical activity. Globally, approximately 15% of the population is affected by migraine at some point in life. Initial recommended management is with simple analgesics such as ibuprofen and acetaminophen for the headache, an antiemetic for the nausea, and the avoidance of triggers. Specific agents such as triptans or ergotamines may be used by those for whom simple analgesics are not effective. All the already available drugs have certain limitations. Either they are unable to produce complete relief or 30-40% patients are no responders or drugs produce adverse effects. A new class of drugs like angiotensin-converting enzyme inhibitors (ACE inhibitors) and angiotensin II receptor antagonists have recently been studied for their off label use in prophylaxis of migraine. Studies done so far, have shown results in favour of their clinical use because of the ability to reduce number of days with headache, number of days with migraine, hours with migraine, headache severity index, level of disability, improved Quality of life and decrease in consumption of specific or nonspecific analgesics. This article reviews the available evidence on the efficacy and safety of these drugs in prophylaxis of migraine. Relevent literatures were chosen, examining the efficacy of angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) for migraine prophylaxis.