THC:Cannabidiol is a one-two punch to knockout pain
Up to eight percent of European adults suffer from neuropathic pain, a debilitating condition that incurs three times more financial burden than a normal control patient. This condition has various causes and is diagnosed using a clinical history or patient complaint. Notably, patients with the condition have identifiable microscopic tissue injury. Fortunately medications such as non-steroidal antiinflammatory drugs — and in severe cases, opiates — help treat the disease. But in a small portion of these adults, the allodynia (non-painful stimuli) or dysesthesias (uncomfortable sensations) become overwhelming and are resistant to medication. New evidence suggests two active constituents in the cannabis plant may be helpful in alleviating these challenges.
Cannabidiol (CBD) and the more popular delta-9-tetrahydrocannibinol (THC) are the titular constituents of Sativex, a sublingual spray marketed by GW Pharmaceuticals (Canada). CBD is not psychoactive and is used off-label for rare forms of epilepsy, and is not regulated in the United States. THC is the more controversial aspect of Sativex, and is responsible for many of marijuana’s psychoactive properties. In the United States, THC is marketed as Marinol and is a Schedule I drug.
A long history of efficacy for both cannibidiol and tetrahydrocannibinol exists in the literature for varying ailments, but not neuropathic pain proper. Based on this foundation, Dr. Kim Smith at the University of New South Wales spearheaded a randomized controlled trial of CBD:THC augmentation. The doses used were 2.7 mg THC / 2.5 mg cannabidiol per spray used up to four times daily. Acetominophen was also allowed as a rescue medication.
More patients in the sample group had a 30% positive response to the admixture than to the placebo group based on patient self-report. The scale used was the Primary Neuropathic Pain index, a 1-10 quantitative descriptor of pain. In other words, the CBD:THC solution was more likely to improve symptoms than placebo. However, several other primary endpoints were not met (including 50% reduction of symptoms, sleep improvement and other secondary endpoints).
“We were pleased with the results. Keep in mind, these patients were refractory to many standard of care treatments. Considering the impact of this devastating illness any little bit of relief helps,” said Dr. Smith said in an e-mail. “It’s a good base to move forward.”
An author not affiliated with the study, Dr. Frederick Mueller, noted it’s not uncommon for variance in responders. “Data in my trials related to improvement in multiple sclerosis spasticity has a subset of great improvement in patients and then almost no improvement. There’s very little between”, he wrote.
Sativex is not currently approved in the United States.