Researchers continue to investigate new ways to prevent migraine, with some surprising results. Sometimes, medications and therapies that were thought to be effective only in easing the pain of an active migraine attack have proven themselves useful as migraine prophylactics. And other treatments have been discovered quite by accident from completely different fields of medicine.

Most people recognize Botox as a cosmetic surgical agent injected to reduce or eliminate fine lines and wrinkles in the skin (known clinically as “hyperfunctional facial lines”), though it has several other indications for the treatment of complex neurological and medical disorders. In the 1990s, when the drug was initially being studied as a cosmetic therapy, researchers noticed a decrease in the frequency and severity of migraine headache in some study subjects who were given Botox. This prompted further investigation into the use of the drug as a migraine treatment, and there are now dozens of published studies on the topic.

Botulinum toxin type A (BoNTA; Botox), is a neurotoxin that is cultured from the anaerobic bacterium Clostridium botulinum, an organism found in soil and water. Once cultured, the toxin is sterilized and vacuum-dried. It is mixed with saline and injected with a fine needle just under the skin, usually into the forehead. The toxin causes short-term muscle paralysis in the area it is injected into, and may have some impact on the nerve fibers that could explain its usefulness in short-term migraine prevention.

As of early 2008, Botox was not yet approved by the FDA for the treatment of chronic migraine, and Allergan (the manufacturer of Botox) was completing phase III clinical trials of the drug for this use.

Botox has few side effects when administered in proper doses by a health care professional. The area surrounding the injection site can become weak if the toxin spreads. Although this is the desired therapeutic effect of the drug, it can be a problem if it spreads to the eyes (causing drooping), throat (causing difficulty swallowing), or other unintended areas.

Several of the analgesic drugs used for acute migraine pain are also sometimes prescribed, with varying success, for migraine prevention. The nonsteroidal anti-inflammatory drugs have already been covered in depth earlier in this chapter.

An older analgesic drug class that has some benefit in migraine prevention is that of the ergot derivatives. One such drug, methysergide (Sansert), is an oral tablet approved for use as a migraine prophylactic. Though it is not effective in treating migraines once they have begun, it is particularly effective as a prophylactic. Unfortunately, because of its side effects, some potentially quite serious with long-term consequences for kidney and cardiovascular function, methysergide is typically not a front-line choice for migraine prevention. See Chapter 7 for more details on ergot derivatives.

Biofeedback — the practice of self-monitoring your body's biological signals and learning how to regulate them through relaxation and visualization techniques — is a proven therapy in the treatment of migraine head pain. It has also been studied as a migraine preventative. The effectiveness of the therapy may be due to the ability of biofeedback and relaxation therapy to reduce stress, a known trigger of migraines.

Because of the psychological benefits and lack of side effects of biofeedback therapy, it is an ideal treatment choice for children and pregnant women, for whom the risks of drug therapy are either too great, or unknown. Turn to Chapter 7 to find out more information on biofeedback therapy.