Preventive therapy usually starts at the onset of the cluster episode but some patients will stay on their prevention medication if they have long lasting episodes or the cluster attacks are becoming more frequent. Which preventive medicine to use often depends on the length and regularity of your episodes. Under the guidance of your doctor, the drugs are usually tapered off once the the cluster episode ends.
The calcium channel blocking agent verapamil (Calan, Verelan, others) is often the first choice for preventing cluster headache. Verapamil is often used in conjunction with other medications. Occasionally, longer term use is needed to manage chronic cluster headache. Constipation is a common side effect of this medication, as well as dizziness, nausea, fatigue, swelling of the ankles and low blood pressure.
Inflammation-suppressing drugs called corticosteroids (steroids), such as prednisone, are fast-acting preventive medications. Corticosteroids are used if your cluster headache has only recently started or if you have a pattern of brief cluster periods and long remissions. Serious side effects make them inappropriate for long-term use.
Lithium (Lithobid) is also effective in preventing chronic cluster headache. Side effects include tremor, increased urination and diarrhea. Frequent blood draws at regular intervals to check for the development of more-serious side effects, such as kidney damage are necessary for this medication.
Ergotamine (Ergomar), available as a tablet that you place under your tongue, can be taken before bed to prevent nighttime attacks. Self-injected or inhalable dihydroergotamine also may be helpful. Ergot medications are effective, but can't be combined with triptans and can only be used for brief periods of time. This drug is used more often for abortive treatment.
Some studies show that 10 milligrams of melatonin taken in the evening may reduce the frequency of cluster headache. This is not usually an effective monotherapy.
Other preventive medications used for cluster headache include anti-seizure medications such as divalproex (Depakote) and topiramate (Topamax), although these can take a long time to become effective which may limit their use in shorter episodes.