Background and aim
Malnutrition in older patients is linked to poor appetite. Cannabis-based medicine may have orexigenic properties in older patients, but this has to our knowledge never been investigated. In older patients, uncertainty applies to the accuracy of estimated glomerular filtration rate (eGFR) based on creatinine, which is crucial for medication prescribing. In older patients with poor appetite, the study aims (1) to assess the efficacy of Sativex® (8.1-mg delta-9-tetrahydrocannabinol [THC] and 7.5-mg cannabidiol [CBD]) to stimulate appetite and (2) to compare the performance of various GFR-estimates and measured-GFR (mGFR) for determining gentamicin clearance utilizing population pharmacokinetic (popPK) modelling methods.

Methods and objectives
This study is composed of two substudies. Substudy 1 is an investigator-initiated single-center, double-blinded, randomized, placebo-controlled, superiority, cross-over study. Substudy 1 will recruit 17 older patients with poor appetite, who will also be invited to substudy 2. Substudy 2 is a single-dose pharmacokinetics study and will recruit 55 patients. Participants will receive Sativex® and placebo in substudy 1 and gentamicin with simultaneous measurements of GFR in substudy 2. The primary endpoints are as follows: Substudy 1—the difference in energy intake between Sativex® and placebo conditions; substudy 2— the accuracy of different eGFR equations compared to mGFR. The secondary endpoints include safety parameters, changes in the appetite hormones, total ghrelin and GLP-1 and subjective appetite sensations, and the creation of popPK models of THC, CBD, and gentamicin.