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Methysergide |
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indicationFor the treatment of vascular headachepharmacologyMethysergide 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 actionMethysergide 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.toxicityFew 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.biotransformationHepaticabsorptionRapiddrug interactionsAcebutolol: Ischemia with risk of gangreneAlmotriptan: 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 |