• An
antihistamine and 5-HT2 receptor antagonist that is structurally
related to tricyclic antidepressants. Has weak anticholinergic
effects and may act as a calcium
channel blocker at high doses. The relative importance of each action in
headache prophylaxis
is unclear. Prevention of cortical
spreading depression may be the mechanism of action for all migraine
preventatives
How Long Until It Works
• Migraines may decrease in as little as 2 weeks, but can take up to 2 months to see full effect
If It Works
• Migraine - goal is a 50% or greater decrease in migraine frequency or severity. Consider tapering or stopping if headaches
remit for more than 6 months or if considering pregnancy
If It Doesn't Work
• Increase to highest tolerated dose
• Migraine: address other issues, such as medication-overuse, other coexisting medical disorders, such as anxiety, and consider
changing to another agent or adding a second agent
Best Augmenting Combos for Partial Response or Treatment-Resistance
• Migraine:
For some patients with migraine, low-dose polytherapy with 2 or more
drugs may be better tolerated and more effective
than high-dose monotherapy. May use
in combination with AEDs, antidepressants, natural products, and
non-medication treatments,
such as biofeedback, to improve
headache control