Abstract text (incl. figure legends and references)

BACKGROUND

Cannabinoid receptors CB1 and CB2 upregulation occurs in pain processing, CB2 agonists suppress neuropathic symptoms. Trigeminal neuralgia (TN), a pain syndrome of neuropathic origin, can be or become refractory to anticonvulsants. Observation concerns cannabinoids in refractory TN of senior patients.

METHOD

Drug: fixed combination 22%Tetrahydrocannabinol (THC), a CB1 CB2 receptor partial agonist +>1%Cannabidiol (CBD) trafficking with CB1 and CB2 receptors

THC/CBD Dose finding: 200 mg/day effective dose

Administration Route: Sublingual to circumvent gastrointestinal adaptation, hepatic first-pass metabolism and producing higher plasma concentration. Non decarboxylated form was chosen to allow entourage effect

Plan: Explanatory-Controlled partly Covered, 3-months treatment, 1-month follow-up

Participants suffered from TN refractory (less than 25% relief) to anticonvulsants. They are part of an observation regarding refractory TN. Hereinafter observation concerns Group A (23 males, 5 females; 57.3+2.2SD) receiving fixed combination THC-/CBD and Group B (20 males, 6 females; 56.9+1.9SD) re-testing carbamazepine 900mg/day. Rescue treatment: lidocaine 2% 10 ml i.v.

RESULTS

Theraputic Effects, Side effects

Pain relief THC/CBD vs Baseline and Carbamazepine treatment p<0.0001

Rescue n=13 Carbamazepine, n=1 THC/CBD

Withdrawal n=7 Carbamazepine, n=2 THC/CBD

Relapse during follow-up n=4 THC/CBD, n=8 Carbamazepine

Somnolence, Drowsiness n=9 Carbamazepine, n=11 females THC/CB first week

Memory (Randt Memory Battery) impairment n=20 Carbamazepine p< 0.5 vs baseline Retrieval amelioration: THC/CBD n=27 p>0.01 vs baseline

Cerebral fMRI changes within the temporal lobe n=3 males Carbamazepine

Sexual intercourses increase n=3 males THC/CBD

CONCLUSIONS

Outcomes suggest either effectiveness and safety of 22%THC+>1%CBD in refractory TN sufferers 50-65 years old or a role for CB1, CB2 receptors in TN. Larger casuistry is needed to guarantee efficacy