Clinical considerations on chronic migraine, pharmacoresistance and refractoriness.

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.