Doctors sometimes prescribe a daily medication to reduce the duration and frequency of migraine attacks. These medications are called prophylactic or preventive therapy. There are several classes of drugs approved for use as prophylactic migraine treatments.

Beta Blockers

No one knows how beta blockers prevent migraines, but they seem to. Beta blockers commonly used in migraine therapy include propranolol (Inderal), nadolol (Corgard), metoprolol (Lopressor, Toprol XL), atenolol (Tenormin), and timolol (Blocadren).

Tricyclic Antidepressants

Tricyclic antidepressants (TCAs) prevent migraine headaches by altering two of the neurotransmitters, nor epinephrine and serotonin, that the nerves in the brain use to communicate. Since migraines and depression are considered comorbid conditions they are a particularly good fit for many migraineurs. TCAs that have been used in migraine therapy include amitriptyline (Elavil), imipramine (Tofranil), doxepin (Sinequan), and imipramine (Tofranil).

Side effects of TCAs include increased heart rate, blurred vision, difficulty urinating, dry mouth, constipation, and weight change.

Anticonvulsants

Antiseizure medications, also called anticonvulsants, have been used to prevent migraine headaches. Like many prophylactic migraine treatments, it is not known how they work to prevent migraines, simply that they do. The anticonvulsants gabapentin, valproic acid, topiramate, and phenobarbital have all been used in migraine therapy.

Calcium-Channel Blockers

Calcium-channel blockers (CCBs), in addition to blocking calcium from entering the muscle cells of the heart, appear to block a serotonin uptake. It is the latter that has caused their occasional use in preventing migraines. The CCBs used in preventing migraines are verapamil (Calan, Verelan, Isoptin), diltiazem (Cardizem, Dilacor, Tiazac), and nimodipine.

Antiserotonin Agents

The antiserotonin agents methysergide and methylergonovine can be used in migraine prophylaxis, but their potential side effects are so severe, including retroperitoneal fibrosis (scarring of tissue around the ureters that carry urine from the kidneys to the bladder) and scarring around the lungs, that they are rarely used in this capacity.