Abstract
All physicians will encounter patients with headaches. Primary headache disorders are common, and often disabling. This paper reviews the principles of drug therapy in headache in adults, focusing on the three commonest disorders presenting in both primary and secondary care: tension-type headache, migraine and cluster headache. The clinical evidence on the basis of which choices can be made between the currently available drug therapies for acute and preventive treatment of these disorders is presented, and information given on the options available for the emergency parenteral treatment of refractory migraine attacks and cluster headache.