Fig. 5. Pharmacokinetic-pharmacodynamic (PK/PD) simulation showing the relative contribution of S-ketamine and S-norketamine to measured effect. Simulated pharmacokinetic (A ) and pharmacodynamic (C ) data assuming placebo pretreatment. Simulated pharmacokinetic (B ) and pharmacodynamic data (D ) assuming rifampicin pretreatment. VAS = visual analog score.