Migraine treatment and the implications of comorbidities

When considering treatment for a person with migraine and comorbid conditions, there are several risks to consider:^{[Silberstein et al., 2007]}

that only one of the conditions will be adequately treated – if a single medication is chosen to treat both conditions, as discussed on the slide, the doses required for each condition may be different
that a suboptimal medication will be chosen, in an effort to use a single pharmacotherapy, overlooking a more optimal approach
that pharmacotherapy will be poorly tolerated because of a third comorbid illness, or a pre-existing condition
that the migraine and the comorbidity will respond to therapy at a substantially different speed. This requires different timelines to be considered when gauging the efficacy of an intervention on both the migraine and the comorbidity.

Reference:
Silberstein SD, Dodick D, Freitag F, et al. Pharmacological approaches to managing migraine and associated comorbidities – clinical considerations for monotherapy versus polytherapy. Headache 2007; 47 (4): 585–599.