Pressor response to intravenous tyramine in healthy subjects after safinamide, a novel neuroprotectant with selective, reversible monoamine oxidase B inhibition

Safinamide is a novel neuroprotectant combining sodium and calcium channel blocking properties with selective, reversible monoamine oxidase type B (MAO B) inhibition. Phase I studies have demonstrated that in healthy volunteers, the ED50 (a dose that inhibits enzyme activity by 50% in 50% of treated subjects) for MAO B inhibition is 87.5 mug/kg/day orally, and that no MAO A inhibition occurs after 10-mg/kg oral dosing. To assess the risk of inducing the "cheese effect," the effect of safinamide and placebo on the pressor response to tyramine was investigated in a group of healthy male volunteers. The study was an open, single-dose placebo-controlled trial with the 2 treatments in sequence. An increase of 30 turn Hg systolic blood pressure was obtained by intravenous tyramine administered by 0.5-mg incremental boluses injected at 15-minute intervals. The amount of tyramine necessary to achieve such a blood pressure increase was the same after the safinamide 2-mg/kg oral load compared with placebo. These results suggest that dietary restrictions for food with high tyramine content should not be required under safinamide treatment.