Which headache medication is contraindicated for patients with peripheral vascular disease?

Ergotamine is contraindicated for patients with peripheral vascular disease primarily due to its mechanism of action and side effects. Ergotamine is a member of the ergot alkaloid class, which works by causing vasoconstriction in the cranial blood vessels to alleviate migraine headaches. However, this vasoconstrictive effect can exacerbate conditions related to peripheral vascular disease, where blood flow to the extremities is already compromised. In these patients, the use of ergotamine could lead to severe complications, such as ischemia or necrosis of tissues due to reduced blood flow.

In contrast, the other medications listed, such as aspirin, acetaminophen, and naproxen, do not have significant vasoconstrictive effects in the same manner as ergotamine. These medications typically manage pain and inflammation without the same risk of exacerbating vascular conditions. Therefore, ergotamine's mechanism directly conflicts with the needs of patients with peripheral vascular disease, making it the medication that should be avoided in such cases.