Calcium-Channel Blockers
Calcium-channel blockers have been prescribed for preventing both migraine and cluster headaches. They must be taken for weeks to months before any benefit is noticed. Certain calcium-channel blockers may be particularly beneficial for preventing migraines in patients who have experienced stroke.
Verapamil (Calan) is most commonly used for prevention of migraines. Others used or being investigated for migraines include diltiazem (Cardizem), nimodipine (Nimotop), nifedipine (Procardia), amlodipine (Norvasc), felodipine (Plendil), and nisoldipine (Sular). Novel calcium blockers, such as dotarizine and flunarizine (Sibelium), are being investigated and show promise for migraines. Flunarizine, available overseas but not in the U.S., is reportedly effective and may help prevent migraines in children. (Other calcium-channel blockers are not useful for children.)
Side Effects. Side effects vary depending on the drug. They may include:
- Fluid accumulation in the feet
- Drop in blood pressure, with accompanying dizziness
- In some people, they cause headaches as severe as the migraines they are preventing
- Constipation
- Fatigue
- Impotence
- Gingivitis
- Flushing, and allergic symptoms
Note: Grapefruit boosts the effects of calcium-channel blocking drugs.
Other Drugs Investigated for Preventing Migraines
Angiotensin Converting Enzyme (ACE) Inhibitors. Commonly used for treating high blood pressure, ACE inhibitors block the production of the protein angiotensin, which constricts blood vessels and may be involved in migraine. Studies using the ACE inhibitor lisinopril (Prinivil, Zestril) are reporting significant reduction in migraine attacks.
Angiotensin-Receptor Blockers (ARBs). Angiotensin-receptor blockers (ARBs) have actions similar to ACE inhibitors, but may have fewer side effects. In one study, patients who took the ARB candesartan (Atacand) experienced significant reduction in the number of headaches compared to patients who received placebo.
Botulinum. Botulinum toxin A (Botox) injections, a common wrinkle treatment, causes small muscles to relax. This approach is now being used with some success for treating disorders that involve over-excited muscle activity, including myofascial pain syndrome and migraine. One study reported complete migraine relief in more than half of patients being tested and improvement of more than 50% in another 35% of patients. Relief lasted 3 - 4 months with no adverse effects. A study presented at the 2005 meeting of the American Headache Society reported that patients who regularly received Botox injections every 3 months reduced both the frequency of migraine attacks and their reliance on pain medications
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