Insufficient management of cancer-associated chronic and neuropathic pain adversely affects patient quality of life. Patients who do not respond well to opioid analgesics, or have severe side effects from the use of traditional analgesics are in need of alternative therapeutic op-tions. Anecdotal evidence suggests that medical cannabis has potential to effectively manage pain in this patient population. This review presents a selection of representative clinical studies, from small pilot studies conducted in 1975, to double-blind placebo-controlled trials conducted in 2014 that evaluated the efficacy of cannabinoid-based therapies containing tetrahydrocannabinol (THC) and cannabidiol (CBD) for reducing cancer-associated pain.

A review of literature published on Medline between 1975 and 2017 identified five clinical studies that evaluated the effect of THC or CBD on controlling cancer pain, which have been reviewed and summarised. Five studies that evaluated THC oil capsules, THC:CBD oromucosal spray (nabiximols), or THC oromucosal sprays found some evidence of cancer pain reduction associated with these therapies. A variety of doses ranging from 2.7-43.2 mg/day THC and 0-40 mg/day CBD were administered. Higher doses of THC were correlated with increased pain relief in some studies.

One study found that significant pain relief was achieved in doses as low as 2.7-10.8 mg THC in combination with 2.5-10.0 mg CBD, but there was conflicting evidence on whether higher doses provide superior pain relief. Some reported side effects include drowsiness, hypotension, mental clouding, and nausea and vomiting. There is evidence suggesting that medical cannabis reduces chronic or neu-ropathic pain in advanced cancer patients.

However, the results of many studies lacked statistical power, in some cases due to limited number of study subjects. Therefore, there is a need for the conduct of further double-blind, placebo-controlled clinical trials with large sample sizes in order to establish the optimal dosage and efficacy of different cannabis-based therapies.

Source: Pubmed

Medical cannabis, or cannabinoid-based products, continues to grow in popularity globally, driving the evolution of regulatory access frameworks; cancer patients and caregivers often rely on guidance from their physicians regarding cannabinoid-based treatments. But the majority of healthcare practitioners still feel unprepared and insufficiently informed to make reasonable, evidence-based recommendations about medical cannabis.

More than 30 countries worldwide have now legalized access to medical cannabis; yet various nations still face arduous regulatory challenges to fulfill the needs of patients, healthcare practitioners, and other medical stakeholders. This has affected the deployment of comprehensive medical cannabis access programs adapted to cultural and social realities.

With a 20-year history of legal medical cannabis access and nearly 400,000 registered patients under its federal access program, Canada serves as a model for countries which are developing their regulatory frameworks. The Canadian clinical experience in cannabinoid-based treatments is also a valuable source of lessons for healthcare professionals who wish to better understand the current evidence examining medical cannabis for oncology patients.

Source: Pubmed

Recently, many countries have enacted new cannabis policies, including decriminalization of cannabis possession as well as legalization of medical and recreational cannabis. In this context, patients and their physicians have had an increasing number of conversations about the risks and benefits of cannabis. While cannabis and cannabinoids continue to be evaluated as pharmacotherapy for medical conditions, the best evidence currently exists for the following medical conditions: chronic pain, neuropathic pain, and spasticity resulting from multiple sclerosis.

We also reviewed the current state of evidence for cannabis and cannabinoids for several other medical conditions, while addressing the potential acute and chronic effects of cannabis use, which are issues that physicians must consider before making an official recommendation on the use of medical cannabis to a patient. As the number of patient requests for medical cannabis has been increasing, physicians must become knowledgeable on the science of medical cannabis and open to a discussion about why the patient feels that medical cannabis may be helpful.