Migraine Prophylaxis

By Annette GallagherMarch 9, 2012No Comments

This begins with the identification and avoidance of triggers, as discussed above, but by no means ends there. Growing clinical evidence and experience suggests that migraine headaches can often be prevented by prophylactic medications. These are sometimes in the anti-convulsant class of medications, such as channel-blockers often used for epilepsy treatments. They can also be in the class of tricyclic anti-depressants, such as amitriptyline. Due to the ongoing stigmatizing of mental disorders, patients should be actively reassured that taking an “anti-depressant” in no way suggests that their pain is “all in their heads” – physical co-localization there notwithstanding!

Except in cases of genuine comorbidity, they are not being given an antidepressant because they have any psychological condition, but because some of the mechanisms causing headaches share certain “nuts and bolts” with those involved in our emotions. For example, the sympathetic nervous system symptoms of migraines likely involve serotonin levels, something that TCAs affect.

A completely different approach to migraine and other chronic headache prevention is the use of either occipital nerve block (ONB) or the use of Botox. Components of nerve block injections are a local anesthetic, such as Lidocaine, and a strong anti-inflammatory medication such as a corticosteroid. Nerve blocks can bring rapid, acute relief from headache pain, probably due to the anesthetic, as well as longer-term relief of up to six weeks, perhaps from the steroidal component. Headache reoccurrence is blunted for an average of four days after nerve block is applied. Patient response to occipital nerve block is quite variable. Tension type headaches seem to not respond well to this treatment but cluster headaches and some migraines do.

Therefore the best candidates for ONB are those with one-sided head pain occurring primarily at the back of the head. There is also some evidence that subsequent rounds of nerve blockade have increasingly positive effects. Unlike trigeminal nerve block for facial neuralgia, ONB has no effect on the muscles of facial expression, a point of reassurance for some patients.

In contrast to nerve block, treatment of muscles with botulinum toxin A, Botox, may require up to two months for any prophylactic benefit to accrue. Nonetheless, as a muscle paralyzing agent, Botox can bring relief to those suffering from tension type headaches that nerve blocks typically fail to touch. Relief of migraine with Botox is variable. Headaches with a pain focus at the top of the head, cheeks or between the eyes have a poorer response to Botox injection. The injections themselves need to be multiple and are typically directed to four main areas: above and between the eyebrows, the forehead, temples, and back of the neck. Each area should get from four to ten separate injections each containing 2.5 to 5.0 units of Botox.

Although a hallmark of migraines is one-sided pain, injections are given in a symmetrical manner to both sides of the head. This is due to clinical experience suggesting migraine can opportunistically appear on the side of the head usually spared when Botox is injected on only the typically afflicted side. Treatments with Botox need to be repeated every three to four months to maintain prophylaxis.