Selection of patients for clinical drug trials in migraine

General concepts and specific factors to be used in the selection of patients for clinical drug trials in migraine are discussed. The definition of common migraine has been unsatisfactory and new diagnostic operational criteria are recommended. Patients with headaches that are a mixture of tension headache and migraine, and migraineurs who have interval headaches which are not clearly differentiated from migraine should be excluded. The headaches should be of moderate to severe degree, in the range of 2-6 per month, and should last from 3 h to 3 days. It would be best for migraine to have been present for at least 1 year, with 3 months retrospective and 2 months prospective observation prior to drug trial. The age of onset of migraine should be below 50, and the age of entry into the study less than 60. Migraineurs in good health, of either sex, are to be included in the study. Occasional use of minor tranquilizers and sedatives as well as of contraceptive drugs is acceptable, but patients who abuse drugs, who are allergic to compounds related to the trial drug and who require major psychotropic medication should be excluded. Also excluded are those whose compliance with the drug trial is doubtful for intellectual or, more often, psychological reasons.