THC absorption from mouth spray varied enormously among older patients, with some absorbing over 15 times more than others

THC pharmacokinetics in older patients showed enormous variability, with coefficient of variation ranging from 40.2% to 152% across pharmacokinetic parameters. A one-compartment model best described THC, with apparent clearance through conversion to THC-OH at 765 L/h. No physiological characteristics including kidney function or body composition significantly influenced pharmacokinetics.

Twenty older medical patients with poor appetite received two fixed doses of Sativex oromucosal spray (2-3 sprays of 2.7 mg THC each, 4 hours apart). Blood samples were collected for 8 hours. Non-linear mixed-effects modeling developed population pharmacokinetic models for THC and its active metabolite THC-OH.

Older adults are an increasingly important population for cannabis-based medicines, yet almost all pharmacokinetic data comes from younger, healthy volunteers. The extreme variability found here means dosing guidelines developed in younger populations may be unreliable for elderly patients.

As cannabis-based medicines expand into indications like appetite loss, pain, and spasticity in older adults, this study provides the first dedicated pharmacokinetic data in this population and reveals a dosing challenge that will need individualized approaches.

Small sample of 20 patients. Single oromucosal product (Sativex). Eight-hour blood sampling may miss later pharmacokinetic phases. Poor appetite itself may affect oromucosal absorption. No comparison with younger adults in the same study.