Safety and pharmacokinetics of oral delta-9-tetrahydrocannabinol in healthy older subjects: a randomized controlled trial

Abstract

There is a great concern about the safety of THC-based drugs in older people (≥65 years), as most of THC-trials did not include such group. In this phase 1, randomized, double-blind, double-dummy, placebo-controlled, cross-over trial, we evaluated the safety and pharmacokinetics of three oral doses of Namisol(®), a novel THC in tablet form, in older subjects. Twelve healthy older subjects (6 male; mean age 72±5 years) randomly received a single oral dose of 3mg, 5mg, or 6.5mg of THC or matching placebo, in a crossover manner, on each intervention day. The data for 11 subjects were included in the analysis. The data of 1 subject were excluded due to non-compliance to study medication. THC was safe and well tolerated. The most frequently reported adverse events (AEs) were drowsiness (27%) and dry mouth (11%). Subjects reported more AEs with THC 6.5mg than with 3mg (p=0.048), 5mg (p=0.034) and placebo (p=0.013). There was a wide inter-individual variability in plasma concentrations of THC. Subjects for whom the Cmax fell within the sampling period (over 2h), Cmax was 1.42-4.57ng/mL and Tmax was 67-92min. The AUC0-2h (n=11) was 1.67-3.51ng/mL. Overall, the pharmacodynamic effects of THC were smaller than effects previously reported in young adults. In conclusion, THC appeared to be safe and well tolerated by healthy older individuals. Data on safety and effectiveness of THC in frail older persons are urgently required, as this population could benefit from the therapeutic applications of THC.

Keywords: Cannabinoids; Delta-9-tetrahydrocannabinol; Elderly; Pharmacokinetics; Safety.