SLV-317

To investigate the pharmacokinetics and the pharmacodynamic effects in dorsal hand veins of the neurokinin‐1 receptor antagonist SLV317.

In a randomized, double‐blind, placebo‐controlled cross‐over study 19 healthy men received a single oral dose of SLV317 or placebo. Blood samples were collected for analysis of SLV317 plasma concentrations and the inhibition of the venodilator response to substance P was evaluated using the hand vein compliance method.

Administration of 250 mg SLV317 as an oral solution was well tolerated and resulted in mean peak plasma concentrations (± SEM) of 77 ± 9 ng ml−1 within 47 ± 3 min; the mean half‐life was 9.9 ± 1.6 h. In hand veins preconstricted with phenylephrine, local infusion of substance P resulted in a mean venodilation of 56 ± 8% and 49 ± 6% (P = 0.91) before administration of SLV317 or placebo, respectively. SLV317 caused a substantial inhibition of substance P‐induced venodilation, whereas placebo had no effect (P < 0.001). The maximum antagonizing effect of SLV317 averaged 95 ± 8% and was observed after 1.47 ± 00.24 h. Correspondingly, the mean area under the effect curve after administration of SLV317 [278 ± 67% h−1; 95% confidence interval (CI) 198, 358] was significantly higher compared with placebo (49 ± 12% h−1; 95% CI −24, 122; P < 0.001).

This study demonstrates that the neurokinin‐1 receptor antagonist SLV317 is an orally active and highly effective antagonist of substance P‐induced effects in humans.