Migraine involves the trigeminal sensory nerve distribution to intra-cranial arteries. These nerves stimulate the release of peptide neurotransmitters which leads to vasodilatation. The peptide neurotransmitters are calcitonin gene-related peptide (CGRP), which is a potent vasodilator, and also substance P and neurokinin A. This action of the neuropeptides may be the immediate cause of a pain response. Characteristics of migraine include aggravation by routine physical activity, moderate or severe intensity, association with nausea and usually it lasts about 4 to 72 hours.

Treatment of migraine

• Ergot Alkaloids - The action of Ergot derivatives specifically relates to the vasoconstriction effects. They have affinity for a wide range of receptors including dopaminergic, serotonergic and adrenergic receptors (alpha), with cause contraction of the smooth muscles. Drug examples are ergotamine, dihydroergotamine and methysergide.

• Triptans - These drugs are currently the first line therapy for acute migraine having a high affinity for 5-HT 1D and 5-HT 1B receptors. The mechanism of action for triptans is the constriction of dilated cranial blood vessels and to inhibit the release of the sensory neuropeptides ( which causes the dilation). Drug examples are sumatriptan, naratriptan and rizatriptan.

• Anti-inflammatory analgesics can be used to control the pain, such as aspirin and ibuprofen.

• Agents for prophylaxis of migraine include beta-blockers like propranolol, antidepressants such as amitriptyline, calcium channel blockers like flunarizine and also anticonvulsants like valproic acid.