In individuals with frequent migrainous attacks, efforts at prevention are worthwhile. The survey by Lipton and colleagues, found approximately one-fourth of patients were appropriate for some form of prophylactic treatment on the basis of the frequency and severity of their headaches, usually more than one severe episode per week. The most effective agents have been beta-adrenergic blockers, certain antiepileptic drugs, and tricyclic antidepressants. Often, comorbidities such as depression, hypertension, epilepsy, or coronary artery disease guide the choice among these three classes of drugs. Some headache specialists have expressed the opinion that amitryptiline may be more effective if headaches are very frequent and that propranolol is more effective if severity of headaches is the concern. Ziegler and colleagues found propranolol and amityrptiline to be equally effective as preventive measures.
Some success has been obtained with propranolol, beginning with 10 to 20 mg two to three times daily and increasing the dosage gradually to as much as 240 mg daily, probably best given as a long-acting preparation in the higher dosage ranges. Under-dosing is a major reason for ineffectiveness. If propranolol is unsuccessful or not tolerated, one of the other beta-blockers, specifically those that lack agonist properties—atenolol (40 to 160 mg/d), timolol (20 to 40 mg/d), or metoprolol (100 to 200 mg/d)—may be effective. Many practitioners have found that particularly young patients do not tolerate the fatigue and other side effects of these medications.
Alternatives, depending upon other comorbidities, are an antiepileptic medication, or our preference, a tricyclic antidepressant. Valproic acid 250 mg taken three to four times daily, other antiepileptic drug such as topiramate, or amitriptyline, 25 to 125 mg nightly may be tried. The newer antidepressants (e.g., specific serotonin reuptake inhibitors) are not as effective and may even cause headache in our experience. If these three main approaches are unsuccessful, calcium channel blockers (e.g., verapamil, 320 to 480 mg/d; nifedipine, 90 to 360 mg/d) are also reportedly effective in decreasing the frequency and severity of migraine attacks in some patients, but there is typically a lag of several weeks before benefit is attained and our success with them has been limited. Indomethacin, 150 to 200 mg/d; and cyproheptadine, 4 to 16 mg/nightly are found to be helpful in some patients and may be particularly useful in preventing predictable attacks of perimenstrual migraine.
A typical experience is for one of these medications to reduce the number and severity of headaches for several months and then to become less effective, whereupon an increase in the dosage, if tolerated, may help; or one of the many alternatives can be tried. The newest putative treatment for chronic or frequently repeating headaches, both migraine and tension, is the injection of botulinum toxin (Botox) into sensitive temporalis and other cranial muscles. Elimination of headaches for 2 to 4 months has been reported—a claim that justifies further study. Similarly, injection blockade of one or both greater occipital nerves or upper cervical roots has reportedly been helpful. Surgical decompression of sensory nerves in the scalp and related techniques have also been advocated but without documentation.
Methysergide, an ergot derivative that was more widely used in the past, in doses of 2 to 6 mg daily for several weeks or months had been effective in the prevention of migraine. Retroperitoneal and pulmonary fibroses are rare but serious complications so that the drug is no longer easily available in the United States or Canada. Some clinicians have used oral methergine as a surrogate but apparently with disappointing results according to our colleagues.