Substance Use

Cannabinoids for Pain

The British Pain Society adds a rational voice to the debate and hype re cannabis and cannabinoids for pain. It confirms what studies and meta-analyses have generally found, that the evidence base for effectiveness is weak. Concerns are expressed for potential side effects especially in terms of misuse, and effects on cognition and mental health (experts have consistently warned on the dangers in teenagers and use during pregnancy).

The Society feels that there is no evidence to support routine use in pain management but acknowledges their use when other modalities fail, and provides strict advice on monitoring and supporting such patients, with a plan to withdraw them when shown ineffective.

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Acute Pain in Buprenorphine-Maintained Patients

Buprenorphine is increasingly encountered as a maintenance agent in substance use disorders rather than Methadone. Analgesia in such patients is challenging due to the complex partial agonist and antagonist properties of this agent.  Strategies include continuing buprenorphine for minor surgeries – often dividing the daily dose, or stopping it before surgery and using other opioids for analgesia in major surgery.

This study found that in those maintained on 12-16mg daily with last dose c. 17 hours ago,  up to 32mg of either IV Hydromorphine or Buprenorphine was effective. “However, the use of hydromorphone for analgesia in buprenorphine-maintained individuals confers greater abuse liability and side effects than does supplemental intravenous buprenorphine”. Analgesia requirement, side effects, drug interactions and factors like whether Buprenorphine is stopped or continued must all be taken into account.

Discontinuing Long-term Opioids in Chronic Pain

Judicious weaning and even discontinuing long term opioids in chronic pain is an option to discuss with patients. Whereas pain may not be fully controllable, quality of life is just as important and that includes the potential harms of opioids – addiction, overdose and death, falls, fractures, constipation, reduced libido, infertility, osteoporosis, sleep-disordered breathing, depression and motor vehicle accidents (link)

This retrospective review suggests that pain is no worse after discontinuing long term opioids especially in mild or moderate pain and may in fact slightly improve. Mechanisms involved may include tolerance and/or hyperalgesia.  The authors caution that nonetheless such patients may remain at risk for mental illness or suicide and careful psychosocial follow up is mandatory, as well as multimodal pain management strategies including non-pharmacological methods.

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Cannabis based medicines for chronic pain

A cautionary tale on cannabis use and users paralleling opioid users for questionable benefit. It is unlikely that cannabinoids are highly effective for chronic non-cancer pain.

“The absence of any clinically relevant beneficial effects of CBM in most systematic reviews, the presence of clinically relevant side effects, and the concerns about long-term risks, make it the duty of physicians prescribing CBM for chronic pain conditions to document and monitor patients carefully by following recent clinical practice guidelines.”

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Cannabis Legalization, physicians and patients

As cannabis becomes legal in Canada, much remains unknown due to lack of research and evidence, or lost in anecdote, hype and marketing. The Newfoundland and Labrador Medical Association provides a helpful site to answer patients’ questions and where physicians may stand if they prescribe medicinal products. In addition, the medical effects,  potential for drug interactions and impacting co-morbidities should be considered in assessing patients.

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Nicotine Replacement in Hospitalized Coronary Patients

Some concern exists as to the cardiac safety of using nicotine replacement patches in cardiac disease. The majority of studies indicate it safe to use in stable disease but this observational study is reassuring in finding: “Among smokers hospitalized for treatment of coronary heart disease, use of nicotine replacement therapy was not associated with any differences in short‐term outcomes”.

Outcomes included inpatient mortality, hospital length of stay, and one-month readmission.

These patients had a high degree of cardiac acuity but the authors caution that, due to the known cardiovascular effects of nicotine, randomized along with longer term studies are needed to confirm these reassuring findings in tackling smoking cessation at an early stage of hospitalization.

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Post-op Opioid Consumption

It would appear that opioid prescription post operatively is still excessive after abdominal surgery. “Postoperative patients might consume less than half of the opioid pills they are prescribed. More research is needed to standardize opioid prescriptions for postoperative pain management while reducing opioid diversion”.  This study shows just how little opioid amounts are needed on average.

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