Current clinical use for cannabis-based drugs
Common uses of medical cannabis are for the treatment of nausea, emesis, anxiety and depression, seizures, cancer, neurogenic diseases, and especially chronic pain. In clinical practice, opioids are still a mainstay for controlling pain, but cannabis-based pharmaceuticals are increasingly used as alternative therapy.
CBD was found to provide adequate analgesia as adjunct therapy to conventional pain medications, including opioids and disease-modifying antirheumatic drugs.1 CBD administered before opioids was found to result in synergy between the opioid and cannabinoid signaling pathways.1
Because effects of long-term medical cannabis use are not fully understood, clinicians should exercise caution when considering CBD and cannabinoid-based therapies. Cannabinoid products were found to have a favorable safety profile in clinical trials and to maintain efficacy during extended periods of use, positing them as appropriate where first- and second-line therapies have failed.
Nabiximols for managing spasticity and chronic pain
Currently approved in Canada and Europe, nabiximols (Sativex) is an oromucosal cannabinoid spray containing a 1:1 ratio of THC to CBD. Nabiximols represent an effective add-on therapy for controlling spasticity and pain in patients with multiple sclerosis. Improvements in secondary end points of sleep and urinary incontinence were also reported by patients with multiple sclerosis.1
The addition of CBD to THC has been shown to increase the beneficial effects of THC while mitigating its adverse effects, including the risk for addiction. Adverse effects associated with nabiximols (ie, dizziness, confusion, dry mouth, headache, and fatigue) were considered mild to moderate and were transient, occurring only during the titration period.1
The ability of nabiximols to alleviate neuropathic pain associated with multiple sclerosis and inflammatory conditions (eg, rheumatoid arthritis) is attributed to the drug’s effect on inflammation and pain on movement.1 THC/CBD oromucosal sprays are being further investigated for the treatment of disorders with similar etiologies, such as poststroke syndrome, migraine headache, and chronic cancer pain.
Plant-derived cannabidiol (Epidiolex)
Epidiolex, a liquid solution for oral delivery of 100 mg/mL CBD, has the advantages over inhalation modes of delivery, of consistent dosing and controlled bioavailability of active components, ensuring optimal therapeutic benefits.2
CBD-associated analgesia offered in products without THC is attributed to agonism of serotonin receptors that are directly involved in anti-inflammatory pathways.1 Epidiolex is devoid of abuse-related effects, and adverse reactions associated with use of the product include somnolence, diarrhea, fatigue, decreased appetite, and elevated transaminase levels, which should be monitored to avoid potential hepatotoxicity.
Epidiolex administered before chemotherapy has been shown to improve neuropathic pain in rats by reducing thermal and mechanical sensitivity. The drug was also shown to improve symptoms of osteoarthritis through its effects on inflammatory markers. Although the analgesic effects of CBD in humans have not been studied extensively, largely because of its classification as a schedule 1 drug, crossover pilot studies show promising results for the use of CBD oral sprays and other cannabinoids for the management of pain.