Usefulness of nabilone as an antiemetic in persistent vomiting due to refractory gastrointestinal disorders.

Nabilone, a synthetic analogue of delta-9-Tetrahydrocannabinol, is an agonist of cannabinoid receptors (CB-1 and CB-2) approved to treat chemotherapy-induced vomiting refractory to antiemetics. Its use in patients with refractory vomiting due to gastrointestinal dysmotility (GID) has not been reported. Our study aims are to assess nabilone usefulness and side-effects in patients with refractory vomiting due to GID. Patients prescribed nabilone at St. Mark's intestinal rehabilitation unit (January 2017 to September 2022) due to GID vomiting have been retrospectively reviewed. Descriptive analysis has been done. Variables measured: age, sex, comorbidities, antiemetics/prokinetics, enteral or parenteral nutrition, nabilone prescription, subjective symptom improvement and side-effects. Seven patients received nabilone. 5/7 (72%) were females. Median age:25 years (23-37). 3/7 (43%) had gastroparesis (1/3 related to postural orthostatic tachycardia syndrome -POTS- , 1/3 to Ehlers-Danlos' Syndrome, POTS, Crohn's Disease and adrenal insufficiency -AI- and 1/3 to sinus node ablation and AI), 2/7 (29%) had gastroparesis and intestinal dysmotility (1/2 related to POTS and 1/2 related to EDS and other connective tissue diseases) and 2/7 (29%) had intestinal dysmotility (1/2 because of polyglucosan body visceral myopathy and 1/2 to intestinal surgery). All patients had received antiemetics or prokinetics before (median of 5 drugs; 2-11). 1/7 (14%) received enteral supplements, 5/7 (72%) enteral nutrition through enteral tubes and 4/7 (57%) parenteral nutrition. 5/7 (72%) patients received 1mg of nabilone bd orally, 1/7 (14%) 2 mg bd through jejunostomy and 1/7 (14%) started nabilone at 2 mg bd orally, but had to be switched to 1 mg bd because of side-effects. The median treatment's duration was 9 days (7-35). Regarding the efficacy of nabilone, 3/7 (43%) had symptomatic improvement. In terms of side-effects 4/7 (57%) patients reported some incidence under the treatment such as headache, light-headedness, drowsiness, dizziness or hallucinations. Patients with refractory GID vomiting despite multiple anti-sickness are difficult to treat. Nabilone improved symptoms in almost half of the patients although adverse effects appeared in more than 50%. Doses higher than 1 mg bd po did not show benefit. Although our study has important limitations, nabilone might be a temporary measure in these patients. Side-effects should be taken into consideration.