A 29-year-old man complains of recurrent severe headaches that usually occur in the early morning. Sometimes he is awakened by the headache "like an alarm clock." The pain comes on quickly, within 5-10 minutes, and it lasts 30 to 60 minutes. He describes the pain as excruciating and stabbing. The pain begins at his left nostril and is followed by severe retro-orbital pain. He experiences tearing and nasal stuffiness on the left side of his face. The patient thinks the headaches started when he was given a promotion at work 3 months ago and his stress levels increased. Which of the following is the best course of treatment?

Choice A reason: SSRIs are not indicated for cluster headaches. These medications are primarily used to treat depression and anxiety and have minimal effect on the pathophysiology of cluster headaches. Choice B reason: Diazepam, a benzodiazepine, may help with anxiety or insomnia but is not effective in aborting or preventing cluster headaches. Choice C reason: This is the correct answer. Cluster headaches are severe, unilateral, stabbing headaches often associated with autonomic symptoms like tearing and nasal congestion. Sumatriptan, a selective serotonin 5-HT1B/1D receptor agonist, is the treatment of choice for acute attacks due to its rapid onset and ability to alleviate pain. Choice D reason: Naproxen, an NSAID, may be effective for tension-type headaches or migraine prophylaxis but is ineffective for acute cluster headache attacks due to the extreme severity and rapid onset of pain.