DIHYDROERGOTAMINE MESYLATE

WARNINGS Dihydroergotamine mesylate injection should only be used where a clear diagnosis of migraine headache has been established. CYP3A4 Inhibitors (e.g. Macrolide Antibiotics and Protease Inhibitors) There have been rare reports of serious adverse events in connection 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 with dihydroergotamine should therefore be avoided ( see CONTRAINDICATIONS ). Examples of some of the more potent CYP3A4 inhibitors include: antifungals ketoconazole and itraconazole, the protease inhibitors ritonavir, nelfinavir, and indinavir, and macrolide antibiotics erythromycin, clarithromycin, and troleandomycin. Other less potent CYP3A4 inhibitors should be administered with caution. Less potent inhibitors include saquinavir, nefazodone, fluconazole, grapefruit juice, fluoxetine, fluvoxamine, zileuton, and clotrimazole. These lists are not exhaustive, and the prescriber should consider the effects on CYP3A4 of other agents being considered for concomitant use with dihydroergotamine. Fibrotic Complications There have been reports of pleural and retroperitoneal fibrosis in patients following prolonged daily use of injectable dihydroergotamine mesylate. Rarely, prolonged daily use of other ergot alkaloid drugs has been associated with cardiac valvular fibrosis. Rare cases have also been reported in association with the use of injectable dihydroergotamine mesylate; however, in those cases, patients also received drugs known to be associated with cardiac valvular fibrosis. Administration of Dihydroergotamine Mesylate Injection, should not exceed the dosing guidelines and should not be used for chronic daily administration ( see DOSAGE AND ADMINISTRATION ). Risk of Myocardial Ischemia and/or Infarction and Other Adverse Cardiac Events Dihydroergotamine mesylate injection should not be used by patients with documented ischemic or vasospastic coronary artery disease. ( See CONTRAINDICATIONS ). It is strongly recommended that dihydroergotamine mesylate injection not be given to patients in whom unrecognized coronary artery disease (CAD) is predicted by the presence of risk factors (e.g., hypertension, hypercholesterolemia, smoker, obesity, diabetes, strong family history of CAD, females who are surgically or physiologically postmenopausal, or males who are over 40 years of age) unless a cardiovascular evaluation provides satisfactory clinical evidence that the patient is reasonably free of coronary artery and ischemic myocardial disease or other significant underlying cardiovascular disease. The sensitivity of cardiac diagnostic procedures to detect cardiovascular disease or predisposition to coronary artery vasospasm is modest, at best. If, during the cardiovascular evaluation, the patient's medical history or electrocardiographic investigations reveal findings indicative of or consistent with coronary artery vasospasm or myocardial ischemia, dihydroergotamine mesylate injection should not be administered. ( See CONTRAINDICATIONS ). For patients with risk factors predictive of CAD who are determined to have a satisfactory cardiovascular evaluation, it is strongly recommended that administration of the first dose of dihydroergotamine mesylate injection take place in the setting of a physician's office or similar medically staffed and equipped facility unless the patient has previously received dihydroergotamine mesylate. Because cardiac ischemia can occur in the absence of clinical symptoms, consideration should be given to obtaining on the first occasion of use an electrocardiogram (ECG) during the interval immediately following dihydroergotamine mesylate injection, in those patients with risk factors. It is recommended that patients who are intermittent long-term users of dihydroergotamine mesylate injection and who have or acquire risk factors predictive of CAD, as described above, undergo periodic interval cardiovascular evaluation as they continue to use dihydroergotamine mesylate injection . The systematic approach described above is currently recommended as a method to identify patients in whom dihydroergotamine mesylate injection may be used to treat migraine headaches with an acceptable margin of cardiovascular safety. Cardiac Events and Fatalities The potential for adverse cardiac events exists. Serious adverse cardiac events, including acute myocardial infarction, life-threatening disturbances of cardiac rhythm, and death have been reported to have occurred following the administration of dihydroergotamine mesylate injection. Considering the extent of use of dihydroergotamine mesylate in patients with migraine, the incidence of these events is extremely low. Drug-Associated Cerebrovascular Events and Fatalities Cerebral hemorrhage, subarachnoid hemorrhage, stroke, and other cerebrovascular events have been reported in patients treated with dihydroergotamine mesylate injection; and some have resulted in fatalities. In a number of cases, it appears possible that the cerebrovascular events were primary, the dihydroergotamine mesylate injection having been administered in the incorrect belief that the symptoms experienced were a consequence of migraine, when they were not. It should be noted that patients with migraine may be at increased risk of certain cerebrovascular events (e.g., stroke, hemorrhage, transient ischemic attack). Other Vasospasm Related Events Dihydroergotamine mesylate injection, like other ergot alkaloids, may cause vasospastic reactions other than coronary artery vasospasm. Myocardial, peripheral vascular, and colonic ischemia have been reported with dihydroergotamine mesylate injection. Dihydroergotamine mesylate injection associated vasospastic phenomena may also cause muscle pains, numbness, coldness, pallor, and cyanosis of the digits. In patients with compromised circulation, persistent vasospasm may result in gangrene or death. Dihydroergotamine mesylate injection should be discontinued immediately if signs or symptoms of vasoconstriction develop. Increase In Blood Pressure Significant elevation in blood pressure has been reported on rare occasions in patients with and without a history of hypertension treated with dihydroergotamine mesylate injection. Dihydroergotamine mesylate injection is contraindicated in patients with uncontrolled hypertension. ( See CONTRAINDICATIONS ). An 18% increase in mean pulmonary artery pressure was seen following dosing with another 5-HT 1 agonist in a study evaluating subjects undergoing cardiac catheterization. Medication Overuse Headache Overuse of acute migraine drugs (e.g., ergotamines, triptans, opioids, or a combination of these drugs for 10 or more days per month) may lead to exacerbation of headache (i.e., medication overuse headache). Medication overuse headache may present as migraine-like daily headaches or as a marked increase in frequency of migraine attacks. Detoxification of patients including withdrawal of the overused drugs and treatment of withdrawal symptoms (which often includes a transient worsening of headache) may be necessary. Preterm Labor Based on the mechanism of action of dihydroergotamine and findings from the published literature, Dihydroergotamine Mesylate Injection may cause preterm labor. Avoid use of Dihydroergotamine Mesylate Injection during pregnancy (see PRECAUTIONS ).