Ergotamine
Mechanism :
Ergotamine acts on migraine by one of two proposed mechanisms: 1) activation of 5-HT1D receptors located on intracranial blood vessels, including those on arterio-venous anastomoses, leads to vasoconstriction, which correlates with the relief of migraine headache, and 2) activation of 5-HT1D receptors on sensory nerve endings of the trigeminal system results in the inhibition of pro-inflammatory neuropeptide release.
Indication :
Contraindications :
Hypersensitivity, peptic ulcer disease, concurrent treatment with protease inhibitors.
Dosing :
1 mg once daily sublingually followed by 1 mg every 30 min as required, no more than 3 mg/episode. Not for very young children.
Adverse Effect :
Vasoconstrictive complications (ischemia, cold extremities, cyanosis, gangrene, absence of pulse, precordial distress and pain), EKG changes, muscle pains, transient tachycardia, bradycardia, hypertension, paresthesia, weakness, numbness, vertigo, nausea and vomiting, localized edema and itching.
Interaction :
Vasoconstrictors: Should not be administered with other vasoconstrictors. Use with sympathomimetics (pressor agents) may cause extreme elevation of blood pressure.
Propranolol: The beta-blocker propranolol has been reported to potentiate the vasoconstrictive action of ergotamine by blocking the vasodilating property of epinephrine.
Nicotine: May provoke vasoconstriction in some patients, predisposing to a greater ischemic response to ergot therapy.
The blood levels of ergotamine-containing drugs are reported to be elevated by the concomitant administration of macrolide antibiotics and vasospastic reactions have been reported with therapeutic doses of the ergotamine-containing drugs when coadministered with these antibiotics.
Hepatic Dose :
Those with hepatic disease may be at increased risk for developing ergot toxicity due to systemic accumulation of ergotamine. Use is contraindicated in hepatic impairment.