Pressor response to oral tyramine during co-administration with safinamide in healthy volunteers

The aim of this study was to evaluate the pressor response to oral tyramine during repeated administration of oral safinamide in healthy volunteers. Twelve females and eight males aged 52.7 +/- 4.9 years entered the study. An oral tyramine screening test was conducted to select subjects sensitive to the tyramine pressor effect on systolic blood pressure (SBP) in the dose range of 200-400 mg. Safinamide 300 mg was then administered once daily under fasting conditions. Starting on day 5 (safinamide pharmacokinetic steady state), single ascending doses of tyramine were co-administered daily: 50, 100 and 200 mg were administered on days 5, 6 and 7, respectively. Vital parameters were monitored by telemetry. No SBP increase a parts per thousand yen30 mmHg over baseline was observed when tyramine was co-administered with safinamide. Less than one third of the 400 mg responders reported SBP increases between 22 and 27 mmHg, which were below the threshold of 30 mmHg over baseline. SBP increases, as well as time interval to pressor response measured after co-treatment with safinamide and tyramine 200 mg, were not significantly different from those measured after administration of oral tyramine 200 mg alone. Safinamide 300 mg, administered o.d. under fasting conditions, does not change the tyramine pressor response as evaluated at steady state after 6-7 days of treatment as compared with the effect of tyramine administered alone. Safinamide, which inhibits monoamine oxidase (MAO)-B, does not affect oral tyramine metabolism mediated mostly by the intestinal MAO-A.