Dihydroergotamine Mesylate Injection USP should only be used where a clear diagnosis of migraine headache has been established. Do not use if you are pregnant or nursing. Do not use if you have high blood pressure or any disease affecting your heart, arteries, or circulation. Use of dihydroergotamine along with potent CYP 3A4 inhibitors, such as protease inhibitors and macrolide antibiotics, has been associated with life-threatening peripheral ischemia and is contraindicated. Serious adverse cardiac events, including acute myocardial infarction, life-threatening disturbances of cardiac rhythm, and death have been reported following the admin-istration of dihydroergotamine mesylate injection. Cerebral hemorrhage, subarachnoid hemorrhage, stroke, and other cerebrovascular events have been reported in patients treated with Dihydroergotamine Mesylate Injection, USP; some resulting in death.