| Indication | For the treatment of vascular headache |
| Pharmacodynamics | Methysergide has been shown, in vitro and in vivo, to inhibit or block the effects of serotonin, a substance which may be involved in the mechanism of vascular headaches. Serotonin has been variously described as a central neurohumoral agent or chemical mediator, as a "headache substance" acting directly or indirectly to lower pain threshold, as an intrinsic "motor hormone" of the gastrointestinal tract, and as a "hormone" involved in connective tissue reparative processes. |
| Mechanism of action | Methysergide is serotonin antagonists acts on central nervous system (CNS), which directly stimulates the smooth muscle leading to vasoconstriction. Some alpha-adrenergic blocking activity has been reported. Suggestions have been made by investigators as to the mechanism whereby Methysergide produces its clinical effects, but this has not been finally established, although it may be related to the antiserotonin effect. |
| Absorption | Rapid |
| Volume of distribution | Not Available |
| Protein binding | Not Available |
| Metabolism | Hepatic |
| Route of elimination | Not Available |
| Half life | Not Available |
| Clearance | Not Available |
| Toxicity | Few cases of acute methysergide intoxication have been reported. The possible symptom complex is therefore not fully known. The following symptoms are based on these few case reports. Euphoria, hyperactivity, tachycardia, dilated pupils, and dizziness have been reported in a child with a dose of 20-24 mg of methysergide. In adults, peripheral vasospasm, with diminished or absent pulses, coldness, mottling and cyanosis, has been observed at a dose of 200 mg. Ischemic tissue damage has not been reported in acute overdosage with methysergide. |