[Cannabinoids reduce opioid use in older patients with pain : Retrospective three-year analysis of data from a general practice]

Dosing of Cannabinoids Associated with an Opioid-Sparing Effect: A Systematic Review of Longitudinal Studies

OBJECTIVE

To assess cannabinoid dosing that could be associated with a reduction in opioid use.

DESIGN

Systematic review conducted according to the PRISMA statement.

DATA SOURCES

PubMed, Embase, Web of Science, and PsycINFO were searched up to December 10, 2022.

REVIEW/ANALYSIS METHODS

We included randomized controlled trials (RCT) and longitudinal observational studies assessing cannabinoids effect on opioid use in patients with acute or chronic pain. Two reviewers independently assessed the studies for inclusion and extracted the data. Tetrahydrocannabinol (THC), Cannabidiol (CBD), and other cannabinoids with dosing were the exposures. Change in opioid doses and opioid discontinuation were the outcomes.

RESULTS

Fifteen studies (including seven RCTs) were included. Eight studies (six observational and two RCTs) were conducted among patients with chronic pain including three with cancer-related pain. Seven studies involved patients with acute pain (five RCTs).In chronic non-cancer pain patients, two observational studies that assessed THC and CBD in combination (average daily dose 17mg/15mg), and one that assessed a CBD-rich extract (31.4 mg/day), showed a significant reduction in opioid use. Of the three studies conducted on patients with cancer, only the observational study that assessed nabilone (average 1.7 mg/day) showed a significant reduction in opioid use. In patients with acute pain, only two observational studies that assessed dronabinol (5mg and 5-10 mg/day for four days) showed a significant reduction in opioid use.

CONCLUSION

The opioid-sparing effect of cannabinoids remains uncertain based on current evidence. However, attention could be paid to cannabinoid doses associated with opioid reduction in included observational studies.

Drug Interactions of Tetrahydrocannabinol and Cannabidiol in Cannabinoid Drugs

BACKGROUND

Cannabinoid drugs containing tetrahydrocannabinol (THC), or its structural analogues, as monotherapeutic agents or as extracts or botanical preparations with or without cannabidiol (CBD) are often prescribed to multimorbid patients who are taking multiple drugs. This raises the question of the risk of drug interactions.

METHODS

This review of the pharmacokinetics and pharmacodynamics of interactions with cannabinoid drugs and their potential effects is based on pertinent publications retrieved by a selective literature search.

RESULTS

As THC and CBD are largely metabolized in the liver, their bioavailability after oral or oral-mucosal administration is low (6-8% and 11-13%, respectively). The plasma concentrations of THC and its active metabolite 11-OH-THC can be increased by strong CYP3A4 inhibitors (verapamil, clarithromycin) and decreased by strong CYP3A4 inductors (rifampicin, carbamazepine). The clinical significance of these effects is unclear because of the variable plasma level and therapeutic spectrum of THC. The metabolism of CBD is less dependent on cytochrome P450 enzymes than that of THC. THC and CBD inhibit CYP2C and CYP3A4; the corresponding clinically relevant drug interactions probably are likely to arise only with THC doses above 30 mg/day and CBD doses above 300 mg/day.

CONCLUSION

Potential drug interactions with THC and CBD are probably of little importance at low or moderate doses. Strong CYP inhibitors or inductors can intensify or weaken their effect. Slowly ramping up the dose of oral cannabinoid drugs can lessen their pharmacodynamic interactions, which can generally be well controlled. Administration by inhalation can worsen the interactions.

Influence of Cannabinoid Treatment on Trajectories of Patient-Related Outcomes in Chronic Pain: Pain Intensity, Emotional Distress, Tolerability and Physical Disability

The treatment of chronic pain with cannabinoids is becoming more widespread and popular among patients. However, studies show that only a few patients experience any benefit from this treatment. It also remains unclear which domains are affected by cannabinoid treatment. Therefore, the present study is novel in that it explores the effects of cannabinoid treatment on four patient-related outcome measures (PROMs), and includes patients with chronic refractory pain conditions who have been given the option of cannabinoid treatment. A retrospective design was used to evaluate the impact of cannabinoid treatment on patients with refractory pain in two German outpatient pain clinics. The present study shows that pain intensity (mean relative reduction (-14.9 ± 22.6%), emotional distress (-9.2 ± 43.5%), pain-associated disability (-7.0 ± 46.5%) and tolerability of pain (-11 ± 23.4%)) improved with cannabinoid treatment. Interestingly, the trajectories of the PROMs seemed to differ between patients, with only 30% of patients responding with respect to pain intensity, but showing improvements in other PROMs. Although the mean treatment effects remained limited, the cumulative magnitude of change in all dimensions may affect patients' quality of life. In summary, a singular evaluation with pain intensity as the sole outcome does not cover the multidimensional effects of cannabinoids. Therefore, the treatment effects of cannabinoids should be evaluated with different PROMs.