Cluster headache; migraine, acute.

1. Sumatriptan succinate is a selective 5-hydroxytryptamine (5HT1) receptor subtype agonist, binding with high affinity to human cloned 5-HT 1B/1D receptors. It exerts its effect by stimulating vasoconstriction in the basilar artery and in the blood vessels of the dura mater, this action is presumed to result in the relief of migraine and cluster headaches.
2. It exhibits a weak affinity for 5-HT1A, 5-HT5A and 5-HT7 receptors and has no pharmacologic activity at dopamine1, dopamine2, muscarinic, or benzodiazepine receptors, or even at 5-HT2, 5-HT3, or 5-HT4 receptor subtypes.

[Absorption]
Tmax, Oral: 2 to 2.5 hours
Tmax, Oral, hepatic impairment: 40 minutes earlier than healthy subjects
Bioavailability, Oral: approximately 15%
Bioavailability, Oral, hepatic impairment: increased
Effect of food: increases Cmax by 15% and AUC by 12%

[Metabolism]
Hepatic: extensive via monoamine oxidase (MAO), predominantly the A isoenzyme
Metabolites: Indole acetic acid, inactive

[Excretion]
Fecal: 40%
Renal: 60% to 80%, 3% to 11% unchanged

[Elimination Half Life]
102 to 186 minutes

Cerebrovascular syndromes, including strokes of any type or transient ischemic attacks;
Concomitant or recent (within 2 weeks) use of an MAO-A inhibitor;
Coronary artery vasospasm, including Prinzmetal angina;
Ergotamine-containing or ergot-type medication use within 24 hours;
Hemiplegic or basilar migraine;
5-HT1 agonist use within 24 hours;
Hypersensitivity to sumatriptan or any of its components;
Intravenous administration; may cause coronary vasospasm;
Ischemic bowel disease;
Ischemic coronary artery disease, including confirmed silent ischemia, angina pectoris, and history of myocardial infarction;
Peripheral vascular disease;
Severe hepatic impairment;
Significant and underlying cardiovascular disease;
Uncontrolled hypertension;
Wolff-Parkinson-White syndrome or arrhythmias associated with other cardiac accessory conduction pathway disorders.

Fetal risk cannot be ruled out. [MDX]

Infant risk cannot be ruled out. [MDX]

[Cardiovascular] Hot and cold flashes (3%), chest pain (?2%), chest pressure (?2%), chest tightness (?2%)
[Central nervous system] Pain (?8%), sensation of pressure (?8%), paresthesia (3% to 5%), fatigue (?3%), feeling of heaviness (?3%), malaise (?3%), sensation of tightness (?3%), heaviness of chest (?2%), vertigo (2%)
[Gastrointestinal] Sore throat (?3%)
[Local] Local pain (2%)
[Neuromuscular & skeletal] Jaw pain (?3%), jaw pressure (?3%), jaw tightness (?3%), neck pain (?3%)
[Respiratory] Pharyngeal edema (?3%)

[Migraine, acute] 25 to 100 mg PO; may repeat after 2 hours if needed; MAX 200 mg/24 hrs

Retreatment after an initial treatment with Imitrex(R) injection, additional single dose up to a MAX of 100 mg/day PO separated by an interval of at least 2 hours between tablet doses.

Safety and efficacy not established in pediatric patients.

Nil.

[Mild to moderate impairment] MAX single dose 50 mg PO
[Severe impairment] Contraindicated.

Store between 2 and 30 degrees C.