| Verapamil | Calcium-channel blocker (heart/blood pressure medicine) | First-line preventative for both episodic and chronic CH. Often the starting point for most patients. | - Strongest evidence for CH prevention - Can dramatically reduce or even stop attacks - Widely used and well-known to neurologists | - Needs ECGs (heart tracing) as dose increases (risk of heart block/slow pulse) - Can cause low blood pressure, constipation, ankle swelling, fatigue - Dose often has to be quite high for CH compared with blood-pressure use |
| Lithium | Mood stabiliser (used in bipolar disorder) | Often used for chronic cluster headache, or when verapamil alone isn’t enough. | - Helpful for some chronic CH patients - Can be combined with other preventatives (e.g. verapamil) | - Requires regular blood tests (drug level, kidneys, thyroid) - Narrow “safe range” (too low = ineffective, too high = toxic) - Can cause tremor, thirst, nausea, weight gain, thyroid and kidney effects - Interacts with many other medicines |
| Topiramate | Anti-seizure / migraine preventative | Used as a second-line preventative in CH, especially if verapamil isn’t tolerated or as an add-on. | - Can help reduce attack frequency for some - Sometimes useful if the person also has migraine | - Side effects can include tingling in hands/feet, weight loss, brain “fog” or word-finding problems, mood changes, kidney stones - Needs slow dose titration and monitoring, especially in people with kidney issues or mood disorders |
| Tegretol® (Carbamazepine) | Anti-seizure drug; first-line for trigeminal neuralgia | Not a standard first-line CH preventative. Occasionally used off-label when other options fail or when there is overlapping trigeminal neuralgia–type pain. | - Targets overactive pain nerves - May help a small subset of patients, especially with facial nerve pain | - Much less evidence for CH than the others - Requires blood tests (liver, blood count, sodium, drug levels) - Can cause drowsiness, dizziness, nausea, low sodium, and rare but serious skin reactions - Has many drug interactions |