THC
Primary psychoactive constituent of cannabis; partial agonist at CB1 and CB2 receptors with analgesic and intoxicating effects.
THC has demonstrated moderate analgesic efficacy in neuropathic pain, with a 2025 systematic review finding small improvements for high THC-to-CBD ratio products. Nabilone reduced pain severity but dronabinol did not reach significance in pooled analysis. THC shows synergistic anti-allodynic effects with gabapentin in preclinical models, improving therapeutic window. Pharmacokinetics are heavily route-dependent, with oral bioavailability limited by first-pass metabolism and high inter-individual variability driven by CYP2C9 polymorphisms. Evidence for long-term safety and efficacy remains limited, and adverse events including dizziness, sedation, and nausea are common.