Fig. 3
Overview of the influence of thyroid dysfunction on the efficacy of antimigraine drugs. Absorption: Increased gut motility in hyperthyroidism might cause decreased absorption. Distribution: Possible comorbid obesity in hypothyroidism may increase distribution of lipophilic drugs. Metabolism: Thyroid hormone reduces CYP3A4 and MAO, decreasing metabolism of some drugs; In hyperthyroidism propranolol is a preferred β-blocker, due to blockage of peripheral conversion of fT4 to fT3. Elimination: Renal clearance can be influenced by thyroid state via either an increased or decreased cardiac output in hyper- and hypothyroidism, respectively