Tag Archives: smoked cannabis

More evidence cannabis can help in neuropathic pain.

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“It’s good to see the trial of smoked cannabis in neuropathic pain reported by Ware and colleagues because smoking is the most common way in which patients try this drug. The authors should be congratulated for tackling the question of whether cannabis helps in neuropathic pain, particularly given that the regulatory hurdles for their trial must have been a nightmare. The question is worth investigating because of the ongoing publicity — which patients see, hear and read — that suggests an analgesic activity of cannabis in neuropathic pain, and because of the paucity of robust evidence for such an analgesic effect. If patients are not achieving a good response with conventional treatment of their pain, then they may, reasonably, wish to try cannabis. If medical cannabis is not available where a patient lives, then obtaining it will take the patient outside of the law, often for the first time in his or her life. Good evidence would at least buttress that decision.”

“This trial adds to the three previous studies of smoked cannabis in neuropathic pain that I could find using PubMed and reference lists…”

“Putting together the four trials of smoked cannabis, the provisional conclusions are that an analgesic effect is evident, that this effect, though not great, may be of use to some patients, and that it often carries with it some adverse effects on the central nervous system (though not obviously so in this trial). These conclusions make biological sense, given that cannabinoids taken orally have shown the same sorts of effects. Interestingly, the “moderate” analgesic effect shown here for neuropathic pain seems to hold true for nociceptive pain.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2950178/

Smoked Medicinal Cannabis for Neuropathic Pain in HIV: A Randomized, Crossover Clinical Trial.

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“In 1999, a report of the United States Institute of Medicine recommended further investigations of the possible benefits of cannabis (marijuana) as a medicinal agent for a variety of conditions, including neuropathic pain due to HIV distal sensory polyneuropathy (DSPN). The most abundant active ingredient in cannabis, tetrahydro-cannabinol (THC), and its synthetic derivatives, produce effective analgesia in most animal models of pain. The antinociceptive effects of THC are mediated through cannabinoid receptors (CB1, CB2) in the central and peripheral nervous systems, which in turn interact with noradrenergic and κ-opioid systems in the spinal cord to modulate the perception of painful stimuli. The endogenous ligand of CB1, anandamide, itself is an effective antinociceptive agent. In open-label clinical trials and one recent controlled trial, medicinal cannabis has shown preliminary efficacy in relieving neuropathic pain.”

“We conducted a clinical trial to assess the impact of smoked cannabis on neuropathic pain in HIV. This was a phase II, double-blind, placebo-controlled, crossover trial of analgesia with smoked cannabis in HIV-associated distal sensory predominant polyneuropathy (DSPN).”

 “…pain relief was greater with cannabis than placebo…”

 “Smoked cannabis was generally well tolerated and effective when added to concomitant analgesic therapy in patients with medically refractory pain due to HIV DSPN.”

“Our findings suggest that cannabinoid therapy may be an effective option for pain relief in patients with medically intractable pain due to HIV-associated DSPN.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3066045/

Impact of cannabidiol on the acute memory and psychotomimetic effects of smoked cannabis: naturalistic study

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“The two main constituents of cannabis, cannabidiol and Δ 9-tetrahydrocannabinol (THC), have opposing effects both pharmacologically and behaviourally when administered in the laboratory. Street cannabis is known to contain varying levels of each cannabinoid.”

“We have recently found evidence to suggest that use of strains richer in cannabidiol may protect cannabis users from the chronic psychotic-like effects of THC. Given the opposing neuropharmacological actions of THC and cannabidiol – the former is a partial agonist whereas the latter is an antagonist at CB1 and CB2 receptors – we hypothesised that cannabidiol may also protect users against other harmful effects of the drug such as cognitive impairment and psychosis-like effects. The current study set out to test these hypotheses by employing a novel methodology that enabled analysis of cannabinoids in the cannabis actually smoked by each individual user.”

“The constituents of street cannabis have changed over the past 20 years with high THC, low-cannabidiol strains now dominating the market. Our findings suggest that this increases the cognitive harms to cannabis users. The research reported here also contributes to the growing body that suggests a range of potential therapeutic uses of cannabidiol, including the ability to modulate the acute amnestic effects of THC. Given the widespread use of cannabis across the globe, there are clear public health implications of this study. In terms of harm reduction, users should be made aware of the higher risk of memory impairment associated with smoking low-cannabidiol strains of cannabis like skunk and encouraged to use strains containing higher levels of cannabidiol.”

Conclusions

“The antagonistic effects of cannabidiol at the CB1 receptor are probably responsible for its profile in smoked cannabis, attenuating the memory-impairing effects of THC. In terms of harm reduction, users should be made aware of the higher risk of memory impairment associated with smoking low-cannabidiol strains of cannabis like ‘skunk’ and encouraged to use strains containing higher levels of cannabidiol.”

http://bjp.rcpsych.org/content/197/4/285.long