A nurse is teaching a client who has a new prescription for ergotamine to treat vascular headaches. The nurse should inform the client that which of the following is a potential adverse effect of this medication?

A. Weight gain: Ergotamine does not typically cause weight gain. Its primary adverse effects are related to vascular and neuromuscular systems rather than metabolic changes. B. Constipation: Constipation is not a common adverse effect of ergotamine. The medication primarily affects smooth muscle in blood vessels rather than gastrointestinal motility. C. Hypoglycemia: Ergotamine does not influence blood glucose levels, so hypoglycemia is not an expected adverse effect. D. Muscle pain: Ergotamine can cause vasoconstriction of peripheral blood vessels, which may lead to muscle pain, weakness, or tingling in the extremities. This neuromuscular effect is a recognized potential adverse effect of the medication.