Overview
DESCRIPTION Dihydroergotamine mesylate is ergotamine hydrogenated in the 9, 10 position as the mesylate salt. Dihydroergotamine mesylate is known chemically as ergotaman-3´,6´,18-trione,9,10-dihydro-12´-hydroxy-2´-methyl-5´-(phenylmethyl)-,(5´α)-, monomethanesulfonate. Its molecular weight is 679.78 and its empirical formula C 34 H 41 N 5 O 8 S.
Mechanism of Action
CLINICAL PHARMACOLOGY Mechanism of Action Dihydroergotamine binds with high affinity to 5-HT 1Dα and 5-HT 1Dβ receptors. It also binds with high affinity to serotonin 5-HT 1A , 5-HT 2A , and 5-HT 2C receptors, noradrenaline α 2A , α 2B and α 1 receptors, and dopamine D 2L and D 3 receptors. The therapeutic activity of dihydroergotamine in migraine is generally attributed to the agonist effect at 5-HT 1D receptors. Two current theories have been proposed to explain the efficacy of 5-HT 1D receptor agonists in migraine. One theory suggests that activation of 5-HT 1D receptors located on intracranial blood vessels, including those on arterio-venous anastomoses, leads to vasoconstriction, which correlates with the relief of migraine headache.
Indications
- INDICATIONS AND USAGE Dihydroergotamine Mesylate Injection is indicated for the acute treatment of migraine headaches with or without aura and the acute treatment of cluster headache episodes.
Common Doses
- 1 mL
- 3 mL
- 2 mL
- 6 mL
Dosage
DOSAGE AND ADMINISTRATION Dihydroergotamine Mesylate Injection should be administered in a dose of 1 mL intravenously, intramuscularly or subcutaneously. The dose can be repeated, as needed, at 1 hour intervals to a total dose of 3 mL for intramuscular or subcutaneous delivery or 2 mL for intravenous delivery in a 24 hour period. The total weekly dosage should not exceed 6 mL. Dihydroergotamine Mesylate Injection should not be used for chronic daily administration.
Black Box Warning
WARNING: PERIPHERAL ISCHEMIA FOLLOWING COADMINISTRATION WITH POTENT CYP3A4 INHIBITORS Serious and/or life-threatening peripheral ischemia has been associated with the co-administration of dihydroergotamine with potent CYP3A4 inhibitors including protease inhibitors and macrolide antibiotics. Because CYP3A4 inhibition elevates the serum levels of dihydroergotamine, the risk for vasospasm leading to cerebral ischemia and/or ischemia of the extremities is increased. Hence, concomitant use of these medications is contraindicated. (See CONTRAINDICATIONS and WARNINGS )
Contraindications
- CONTRAINDICATIONS There have been a few reports of serious adverse events associated with the coadministration of dihydroergotamine and potent CYP3A4 inhibitors, such as protease inhibitors and macrolide antibiotics, resulting in vasospasm that led to cerebral ischemia and/or ischemia of the extremities. The use of potent CYP3A4 inhibitors (i.e., ritonavir, nelfinavir, indinavir, erythromycin, clarithromycin, troleandomycin, ketoconazole, itraconazole) with dihydroergotamine is, therefore contraindicated (See WARNINGS: CYP3A4 Inhibitors ).
Side Effects
- ADVERSE REACTIONS Serious cardiac events, including some that have been fatal, have occurred following use of Dihydroergotamine Mesylate Injection but are extremely rare. Events reported have included coronary artery vasospasm, transient myocardial ischemia, myocardial infarction, ventricular tachycardia, and ventricular fibrillation. (See CONTRAINDICATIONS , WARNINGS , and PRECAUTIONS .). Fibrotic complications have been reported in association with long term use of injectable dihydroergotamine mesylate (See WARNINGS: Fibrotic Complications ).
Interactions
- Drug Interactions Vasoconstrictors Dihydroergotamine Mesylate Injection should not be used with peripheral vasoconstrictors because the combination may cause synergistic elevation of blood pressure. Sumatriptan Sumatriptan has been reported to cause coronary artery vasospasm, and its effect could be additive with Dihydroergotamine Mesylate Injection. Sumatriptan and Dihydroergotamine Mesylate Injection should not be taken within 24 hours of each other. (See CONTRAINDICATIONS .