A Study to Evaluate the Safety and Tolerability of Rizatriptan for Long Term Treatment of Acute Migraine in Children and Adolescents (MK-0462-086 AM3)

Inclusion Criteria: * Patient is between 12 and 17 years of age inclusive at screening Visit 1 * Patient weighs at least 20 kg (44 pounds) * Patient has had a history of unilateral or bilateral migraine headache with or without aura \>6 months with ≥1 to ≤8 mild, moderate or severe migraine attacks per month in the 2 months prior to screening Visit 1 * Patient has a history of migraine defined by International Headache Society (IHS) migraine definitions * The parent or guardian and patient agree to the patient's participation in the study as indicated by parental/guardian signature on the consent form and patient assent * For patients taking migraine prophylactic medication, treatment regimen is stable and has been taken for at least 3 months prior to Visit 1 Exclusion Criteria: * Patient is pregnant or breast-feeding, or is a female expecting to conceive within the projected duration of study participation * Patient has a history of mild migraine attacks or migraines that resolve in less than 2 hours * Patient has basilar or hemiplegic migraine headaches * Patient has \>15 headache-days per month OR has taken medication for acute headache on more than 10 days per month in any of the 3 months prior to screening * Patient has uncontrolled high blood pressure, uncontrolled diabetes, human immunodeficiency virus (HIV), any cancer, or any other significant disease * Patient has a history cardiovascular problems or stroke * Patient has either demonstrated hypersensitivity to or experienced a serious adverse event in response to rizatriptan * Patient has demonstrated hypersensitivity to or experienced a serious adverse event in response to 3 or more classes of drugs (over-the-counter and prescription) * Patient did not experience satisfactory relief from migraine pain to prior treatment with 2 or more adequate courses of 5-hydroxytryptamine 1 (5HT1) agonists * Patient has a recent history (within the past year) or current evidence of drug or alcohol abuse or is a "recreational user" of illicit drugs * Patient is currently taking monoamine oxidase inhibitors, methysergide, or propranolol, and is unable to tolerate withdrawal of these medications for the intervals required * Patient is currently participating or has participated in a study with an investigational compound or device within 30 days of screening * Patient is legally or mentally incapacitated