A nurse is teaching a client who has a new prescription for sumatriptan to treat migraine headaches. Which instruction would the nurse include?

A. Take daily to prevent headaches: Sumatriptan is not used as a preventive medication for migraines. It is intended for acute migraine attacks and should only be taken when symptoms begin, not on a daily schedule. B. Repeat dose in 1 hour for unrelieved headache: The repeat dosing interval for sumatriptan is usually at least 2 hours, not 1 hour. Taking it too soon increases the risk of adverse cardiovascular effects. C. Report chest pain and tightness to the healthcare provider: Sumatriptan can cause coronary vasospasm, leading to chest pain, tightness, or even myocardial ischemia. Clients must promptly report these symptoms to ensure safety and prevent cardiac complications. D. Oral sumatriptan is the fastest route of administration: Oral tablets are effective but not the fastest. Subcutaneous injection provides the quickest relief, followed by intranasal spray, making oral administration the slowest of the available routes.