General Principles of Migraine Prophylaxis
There are no sound criteria for preferring one prophylactic drug over another. However, the following should be taken into account (1) Comorbidities (2) Drug interactions (3) Possible side effects (4) Lifestyle issues e.g. a preventative that lead to weight gain may not be the best option in young women with a tendency to gain weight.
A once daily dose can help improve patient compliance.
Start low and go slow. To minimise possible side effects, patients should be started on the lowest dose of a prophylactic medicine and increased gradually if required.
Allow an adequate time for the drug to show benefit. An appropriate trial length for most preventive medications is 8 to 12 weeks. Patients should be maintained on preventatives for at least 6 -9 months before reduction and gradual withdrawal is considered.
As with acute treatments, many patients will not respond well to certain medications and responses cannot be predicted.
Patients should keep a Migraine Diary to record of the frequency, severity, and duration of attacks and of medications consumed for each attack. This is the most reliable way to know if the preventive medication is having the desired effect.
Remember that while on a course of prophlyactic treatment, patients still need to have access to an effective acute treatment to deal with breakthrough attacks.