Abstract
Patients with chronic migraine are difficult to treat and often analgesic overusers. In this article attention is focused on aspects considered important for producing a definition of refractory in relation to this headache form. I propose that a "chronic migraine" patient should be considered "refractory" to pharmacological prophylaxis when adequate trials of preventive therapies at adequate doses have failed to reduce headache frequency and improve headache-related disability and, in patients with medication overuse, also failed to reduce the consumption of symptomatic drugs.