Which medication is commonly used for the prevention of cluster headaches?

Verapamil is commonly used for the prevention of cluster headaches due to its effectiveness as a calcium channel blocker. It works by inhibiting calcium influx into vascular smooth muscle and cardiac muscle, which can help in stabilizing vascular tone and reducing the frequency and severity of cluster headache attacks. The drug has been shown in clinical studies to significantly decrease the incidence of these intense headaches, making it a primary treatment choice for this specific condition.

Topiramate is often used to prevent migraines and is not the first-line choice for cluster headaches, while phenytoin and lamotrigine are primarily used for seizure disorders and mood stabilization, respectively, and do not have substantial evidence supporting their use in the prevention of cluster headaches. Hence, verapamil stands out as the most appropriate option for preventing cluster headaches among the listed choices.