indication

For the treatment of vascular headache

pharmacology

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.

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.

biotransformation

Hepatic

absorption

Rapid

drug interactions

Acebutolol: Ischemia with risk of gangrene

Almotriptan: Possible severe and prolonged vasoconstriction

Amyl Nitrite: Possible antagonism of action

Atenolol: Ischemia with risk of gangrene

Betaxolol: Ischemia with risk of gangrene

Bevantolol: Ischemia with risk of gangrene

Bisoprolol: Ischemia with risk of gangrene

Carteolol: Ischemia with risk of gangrene

Carvedilol: Ischemia with risk of gangrene

Clarithromycin: Risk of ergotism and severe ischemia with this association

Delavirdine: The antiretroviral agent may increase the ergot derivative toxicity

Efavirenz: The antiretroviral agent may increase the ergot derivative toxicity

Eletriptan: Possible severe and prolonged vasoconstriction

Erythrityl Tetranitrate: Possible antagonism of action

Erythromycin: Possible ergotism and severe ischemia with this combination

Esmolol: Ischemia with risk of gangrene

Frovatriptan: Possible severe and prolonged vasoconstriction

Isosorbide Dinitrate: Possible antagonism of action

Isosorbide Mononitrate: Possible antagonism of action

Josamycin: Possible ergotism and severe ischemia with this combination

Labetalol: Ischemia with risk of gangrene

Metoprolol: Ischemia with risk of gangrene

Nadolol: Ischemia with risk of gangrene

Naratriptan: Possible severe and prolonged vasoconstriction.

Nitroglycerin: Possible antagonism of action

Oxprenolol: Ischemia with risk of gangrene

Penbutolol: Ischemia with risk of gangrene

Pindolol: Ischemia with risk of gangrene

Posaconazole: Contraindicated co-administration

Practolol: Ischemia with risk of gangrene

Propranolol: Ischemia with risk of gangrene

Rizatriptan: Possible severe and prolonged vasoconstriction

Sibutramine: Possible serotoninergic syndrome

Sotalol: Ischemia with risk of gangrene

Sumatriptan: Possible severe and prolonged vasoconstriction

Telithromycin: Risk of ergotism and severe ischemia with this association

Timolol: Ischemia with risk of gangrene

Troleandomycin: Possible ergotism and severe ischemia with this combination

Zolmitriptan: Possible severe and prolonged vasoconstriction