Ascending‐Dose Study of Controlled‐Release Ketamine Tablets in Healthy Volunteers: Pharmacokinetics, Pharmacodynamics, Safety, and Tolerability

Summary

Oral controlled-release ketamine tablets improve safety and tolerability compared with injected ketamine by reducing peak drug exposures. In a randomized, placebo-controlled ascending-dose study of 24 healthy volunteers, doses of 60, 120, or 240 mg or placebo were given. Drug release occurred over about 10 hours, with most drug present as norketamine (approximately 90%). Elimination half-life was prolonged (7–9 hours) versus published data from immediate-release oral forms. No changes in blood pressure or heart rate occurred after any dose. Mild dissociation was reported only after 240 mg, with mean ratings of 1–2 out of 76. No clinically significant ECG or lab changes were observed. Reducing and delaying peak ketamine concentration improves tolerability for patients with depression or anxiety.

Study at a glance

Abstract

Parenteral ketamine has fast‐onset antidepressant and antianxiety effects; however, it causes dissociation, hypertension, and tachycardia shortly after dosing. Ketamine's antidepressant effects may be due to active metabolites rather than to ketamine itself. We hypothesized that oral controlled‐release ketamine tablets would improve safety and tolerability compared with injected ketamine by reducing peak ketamine exposures compared with dosing by injection. In this randomized, placebo‐controlled ascending‐dose study, ketamine doses of 60, 120, or 240 mg or matching placebo (single dose followed by every‐12‐hours dosing for 5 doses) were given to 24 healthy volunteers. Pharmacokinetics, pharmacodynamics (brain‐derived neurotropic factor), adverse events, and vital signs were assessed up to 72 hours. Drug release occurred over ∼10 hours, with most drug substance present as norketamine (∼90%). Area under the concentration‐time curve and peak concentration were dose proportional. Elimination half‐life was prolonged (7‐9 hours) compared with published data from immediate‐release oral formulations. There were no changes in blood pressure or heart rate after any dose. Mild dissociation was reported after 240 mg but not lower doses; mean dissociation ratings in this group were minimal (1‐2/76). There were no clinically significant changes in ECGs or safety laboratory tests at any time. Compared with injected ketamine, oral controlled‐release ketamine tablets did not increase blood pressure or heart rate, and only at doses of 240 mg was dissociation of mild intensity reported. Reducing and delaying ketamine peak concentration by oral dosing with controlled‐release ketamine tablets improve this drug's tolerability for patients with depression/anxiety.