Self-reported cannabis use to manage opioid withdrawal symptoms and reductions in opioid use among people who use unregulated opioids: a cross-sectional analysis

Background: Opioid withdrawal is a significant challenge for people seeking to reduce or eliminate opioid use, and unmanaged withdrawal increases the risk of relapse and overdose. Using cannabis to manage opioid withdrawal has been reported by people who use opioids, yet it is not clear whether this leads to reductions in opioid use. Moreover, because pain is prevalent among people who use unregulated opioids (PWUO) and may contribute to ongoing opioid use, the effects of cannabis use to manage withdrawal symptoms may differ among individuals experiencing moderate to severe pain. We investigated the relationship between cannabis use to manage unregulated opioid withdrawal and self-reported reductions in opioid use among PWUO.

Methods: Data were derived from a cross-sectional questionnaire administered to cannabis-using PWUO in Vancouver, Canada, between December 2019 and November 2021. Multivariable logistic regression estimated the associations between cannabis use for opioid withdrawal and self-reported reductions in opioid use. A sub-analysis explored if these associations varied among participants living with and without moderate to severe pain.

Results: Among 197 participants, 89 (45.2%) reported cannabis use to manage symptoms of opioid withdrawal in the past six months. In multivariable analysis, cannabis use for opioid withdrawal was significantly associated with self-reported reductions in opioid use (adjusted Odds Ratio [AOR] = 2.16, 95% Confidence Interval [CI]: 1.13-4.19) in the same time period. In a sub-analysis, this association was only significant among participants with moderate to severe pain (AOR = 6.55; 95% CI: 2.44-19.63).

Conclusions: We observed a significant association between self-reported use of cannabis to manage unregulated opioid withdrawal and reductions in opioid use among cannabis-using PWUO living with pain. Aligned with other studies, these findings support conducting experimental trials of cannabinoids to support individuals experiencing opioid withdrawal and living with pain.”

https://pubmed.ncbi.nlm.nih.gov/42343486

https://link.springer.com/article/10.1186/s42238-026-00458-0

Development and clinical evaluation of a nanoemulsion for buccal delivery of cannabis extract in refractory chronic pain

“Cannabinoid-based therapies have gained increasing attention for the management of chronic and treatment-resistant pain, although their clinical application is limited by the poor aqueous solubility and variable bioavailability of Δ9-tetrahydrocannabinol (THC).

In this study, we developed and characterized a nanoemulsion (THC-NE) for buccal administration of a Cannabis sativa L. extract (Bedrocan®), with the aim of improving solubility, stability and bioavailability.

The optimized formulation, composed of pharmaceutically acceptable excipients, showed a narrow droplet size distribution (DH ≈ 73 nm, PDI ≈ 0.2), a THC content consistent with the theoretical value (3.53 ± 0.56 mg/mL), and good physicochemical stability at 4°C for at least 90 days. The formulation maintained its properties upon extensive dilution in simulated buccal fluids and after spray nebulization, supporting its suitability for oromucosal delivery. In vitro release studies confirmed sustained THC release from THC-NE, whereas negligible release was observed from the oil extract, highlighting the role of nanoformulation in enhancing solubilization and controlled release.

An observational study was conducted in 18 patients with chronic pain unresponsive to standard treatments. After a median follow-up of 189 days, mean pain scores (NRS) decreased significantly from 8.6 ± 0.9 to 5.4 ± 2.8 (p < 0.001), with 83% of patients achieving a ≥ 20% reduction. Among responders, the mean NRS decreased by 45% and treatment persistence was found to be high, with 64% of patients still remaining under therapy after six months. A total of 17 adverse events were reported in 11 patients, most of which were mild to moderate and transient. Additionally, treatment interruption occurred in three patients due to adverse events, in other three owing to limited efficacy and in two for logistical reasons.

Overall, these findings indicate that buccal administration of THC-NE represents a promising patient-friendly approach for cannabis-based therapy, offering improved solubility, controlled release and meaningful clinical benefit in patients with refractory chronic pain.”

https://pubmed.ncbi.nlm.nih.gov/42336000

“Among the bioactive compounds found in Cannabis sativa, Δ9-tetrahydrocannabinol (THC) has been identified as the primary psychoactive component, exhibiting significant analgesic, antispastic, and neuroprotective properties. “

“This study demonstrates that NE technology can be successfully applied to develop a stable and efficient buccal formulation of Cannabis sativa extract. The optimized THC-NE proved to be physicochemically stable, robust under dilution, and suitable for administration via standard spray devices, while ensuring enhanced release of THC compared to the oily extract.”

https://www.sciencedirect.com/science/article/pii/S0939641126001839?via%3Dihub

Case Report: Oral and topical chronic administration of THC-rich and CBD-rich cannabis oil as palliative care in a rescued horse with open wound, sarcoid and chronic pain

“Cannabinoid-based therapies have shown analgesic, anti-inflammatory, and wound-healing potential across veterinary species; however, clinical data on long-term use of THC-rich formulations in horses remain scarce.

This case report describes the use of combined oral and topical THC-rich and CBD-rich full-spectrum cannabis oils as part of a palliative care strategy in a rescued horse with severe chronic disease.

A senior mixed-breed gelding was rescued with a large, chronic ulcerative lesion of the left hind limb, severe malnutrition, non-weight-bearing lameness (AAEP grade 5/5), and refractory pain. Diagnostic workup identified a fibroblastic equine sarcoid complicated by complete suspensory tendon rupture, early osteomyelitis, and chronic joint disease. Conventional medical and surgical options were limited due to poor response, disease severity, and resource constraints.

A long-term palliative protocol was initiated using oral THC-rich and CBD-rich full-spectrum cannabis oils (1:1 ratio; 100 mg/mL each) with gradual dose escalation to a target of 0.5 mg/kg of each compound every 12 hours. The same formulation was applied topically to the wound once to twice daily. Treatment duration was 10 months, with concurrent multimodal analgesia as needed.

Cannabinoid therapy was associated with sustained improvements in appetite, body condition, pain, and mobility. Marked wound improvement was observed, including reduced granulation tissue, improved epithelialization, and resolution of self-mutilation.

No clinically relevant adverse effects or laboratory abnormalities occurred during routine dosing. Transient ataxia and sedation were noted only at high rescue doses near end of life. Despite eventual disease progression and euthanasia due to refractory pain, quality of life was substantially improved for most of the treatment period.

This case supports the potential role of combined THC-rich and CBD-rich cannabis oils as a safe and effective adjunct in multimodal palliative care for horses with chronic, refractory conditions. Controlled studies are warranted to define optimal dosing and indications.”

https://pubmed.ncbi.nlm.nih.gov/42311392

“Across veterinary species, cannabinoids have shown therapeutic potential with favorable safety and tolerability profiles.”

“The aim of this case report is to describe a long-term multimodal clinical approach using cannabinoids (THC and CBD) in a rescued horse affected by a wound/sarcoid and joint disease, as part of a palliative care strategy for pain management, inflammation control, and wound-healing enhancement.”

“This case suggests that long-term administration of THC-rich and CBD-rich cannabis oils may be a useful adjunct for palliative management in horses with chronic, refractory conditions.”

“Cannabinoid therapy was associated with improved comfort, mobility, and quality of life, supporting its potential role within multimodal palliative care.”

https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2026.1794084/full


Benefits of Medical Cannabis in Patients With Pain Registered in the Minnesota Medical Cannabis Program

Purpose: Medical cannabis is commonly used to treat chronic pain. Clinical trials typically use only one type and dosage of medical cannabis product, which is not reflective of real-world use. The use of a state-run medical cannabis program can bridge the gap between clinical research and real-world use of medical cannabis to estimate the benefits of cannabis use on patient symptoms. This study aimed to describe medical cannabis use among patients with intractable and chronic pain in the Minnesota Medical Cannabis Program and estimate pain reduction benefits received from medical cannabis.

Methods: Patients who enrolled in the Minnesota Medical Cannabis Program between March 2022 and February 2023 for chronic pain and purchased medical cannabis for at least 8 months were included in this study. Patients were required to complete the Patient Self-Evaluation before each medical cannabis purchase, which included the PEG (Pain, Enjoyment of Life, and General Activity) scale. The main outcome of this analysis was a ≥30% change in PEG component score within 4 months of first medical cannabis purchase. The proportion of patients who maintained that reduction for an additional 4 months was also calculated. Medical cannabis product purchases were queried from the first 4 months in the program and categorized by route of administration and tetrahydrocannabinol:cannabidiol ratio. Medical cannabis purchasing profiles were created using k-means clustering to group patients who purchased similar proportions of product types. Adjusted logistic regression models were run to investigate the association between medical cannabis purchasing profile and reporting ≥30% reduction in PEG score.

Findings: Among patients reporting moderate-to-severe scores at program enrollment, 54.9% reported a ≥30% score improvement for life enjoyment, 54.7% reported improvement in general activity interference, and 40.8% reported improvement in pain score within 4 months of their first purchase. Cannabis flower products were most commonly purchased by patients. High tetrahydrocannabinol:cannabidiol products were the most commonly purchased in all medical cannabis product categories. K-means clustering created 5 product purchasing profiles, which were not associated with PEG score improvement outcomes after adjustment for number of purchasing transactions.

Implications: Medical cannabis patients report reduction in PEG scores within 4 months of first medical cannabis purchase using a variety of medical cannabis products. Future research on medical cannabis should determine the frequency of use of different products and administration methods to further investigate how cannabis can be used for effective pain management in patients with chronic pain.”

https://pubmed.ncbi.nlm.nih.gov/42303550

“Medical cannabis patients report improvement in pain symptoms after four months.”

https://www.clinicaltherapeutics.com/article/S0149-2918(26)00187-6/fulltext

Therapeutic potential of endocannabinoid system activation in opioid use disorder and pain

Introduction: Opioid use disorder (OUD) and chronic pain remain major global health challenges. Although opioid-based therapies provide effective analgesia, their long-term use is limited by safety concerns, dependence, and variable efficacy. Modulation of the endocannabinoid system (ECS) has emerged as a promising therapeutic strategy for pain management and opioid-related disorders.

Areas covered: This narrative review summarizes current evidence on ECS-targeted interventions for OUD, chronic non-cancer pain, and cancer-related pain. Relevant literature was identified through PubMed using search terms related to the ECS, cannabinoid receptors (CB1 and CB2), phytocannabinoids (Δ9 -tetrahydrocannabinol [THC] and cannabidiol [CBD]), synthetic cannabinoids, fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) inhibitors, and opioid – cannabinoid interactions. Particular emphasis is placed on mechanistic interactions between ECS and opioid signaling pathways, as well as evidence from preclinical and clinical studies evaluating therapeutic efficacy and safety.

Expert opinion: ECS modulation may alleviate pain, reduce opioid withdrawal symptoms, and improve affective outcomes. Interactions between cannabinoid and opioid receptors may produce synergistic analgesic effects while potentially mitigating opioid tolerance and dependence. However, clinical translation remains limited by small sample sizes, heterogeneous study populations, and variability in trial design. Well-controlled clinical trials are needed to establish optimal dosing strategies, evaluate long-term safety, and clarify the therapeutic role of ECS-targeted interventions in OUD and pain management.”

https://pubmed.ncbi.nlm.nih.gov/42295097

“The endocannabinoid system (ECS) represents a promising therapeutic target for opioid use disorder (OUD), chronic non-cancer pain, and cancer-related pain.”

“Cannabinoids (e.g., CBD and Δ9 -THC) exert analgesic and anti-inflammatory effects through CB1-mediated central mechanisms and CB2-mediated peripheral mechanisms.”

https://www.tandfonline.com/doi/full/10.1080/14728222.2026.2690138

Targeting Phantom Limb Pain with Cannabinoids in a Rat Model

“Introduction: Phantom limb pain (PLP) is a debilitating neuropathic condition arising after limb loss or nerve injury, with limited effective treatments. Cannabinoids, including cannabidiol (CBD), β-caryophyllene (BCP), and Δ9-tetrahydrocannabinol (THC), possess analgesic and anti-inflammatory properties. This study evaluated their combined efficacy as preventive or delayed interventions in a rodent model of PLP.

Methods: To model PLP, a chronic constriction injury was used to mimic pre-amputation pain, followed by formalin-induced localized inflammation and complete sciatic nerve transection to simulate extremity amputation. Cannabinoid treatments (CBD/BCP/THC, CBD/BCP, or THC) or vehicle control were administered either preemptively on the day of axotomy (prevention paradigm) or after the emergence of pain behaviors (reversal paradigm). Progression of pain behaviors were assessed over a 72-day period, and modulation of spinal cytokine levels, glial reactivity, and GABAergic signaling was evaluated.

Results: Preemptive THC or CBD/BCP reduced PLP onset and severity, while the full combination was less effective. In contrast, with delayed treatment, CBD/BCP and the CBD/BCP/THC combination were most effective in mitigating PLP. Pain reduction was correlated with restoration of spinal GABAergic inhibition. All cannabinoid treatments decreased microglial and astrocyte reactivity and shifted cytokines toward an anti-inflammatory state.

Conclusion: Cannabinoid-based interventions demonstrate significant therapeutic promise for PLP, showing efficacy as both early and delayed treatments. Findings suggest that THC may exert greater therapeutic effects when administered pre-emptively, while CBD and BCP may offer greater therapeutic advantages in established pain states. These findings highlight the therapeutic potential of tailored cannabinoid interventions for neuropathic pain and underscore the importance of optimizing dosing strategies for maximal analgesic effect.”

https://pubmed.ncbi.nlm.nih.gov/42267080

“Cannabis contains a complex mixture of cannabinoids, terpenes, and flavonoids that have demonstrated therapeutic potential in a variety of pathologies and conditions. Their anti-inflammatory, analgesic, and antioxidant activities are believed to play a central role in mediating pain relief.”

“Our findings support the therapeutic potential of cannabinoid-based treatments in both preventing and reversing PLP, with efficacy varying by cannabinoid pairing and timing of treatment.

Together, these results underscore the therapeutic promise of cannabinoid-based treatments while highlighting the need to carefully consider how specific compounds and dosing strategies interact in different stages of pain.”

https://karger.com/mca/article/9/1/92/946968/Targeting-Phantom-Limb-Pain-with-Cannabinoids-in-a

High-dose cannabidiol for chronic neuropathic pain associated with spinal cord injury: a randomised clinical trial

Background: Chronic neuropathic pain is common after spinal cord injury (SCI), yet current treatments have limited efficacy and significant side effects. Cannabidiol (CBD), a non-intoxicating component of cannabis, has demonstrated efficacy in preclinical neuropathic pain models. Here, we investigated the effect of high-dose (up to 800 mg/day) CBD on chronic neuropathic pain in SCI.

Methods: This randomised, double-blinded, placebo-controlled, crossover clinical trial was conducted at Neuroscience Research Australia. Adults with SCI and neuropathic pain (≥three months duration) were recruited. Participants were randomised to one of two treatment orders by an unblinded investigator who had no participant contact. Participants and all other investigators were blinded. Participants consumed oral CBD and placebo over two six-week treatment periods separated by a four-week washout. Treatment was titrated up to 800 mg/day of CBD over two-weeks. The primary outcome was change in self-reported pain intensity on a zero (no pain) to ten (worst pain imaginable) Visual Analogue Scale. Statistical comparisons included CBD versus placebo treatment, and pre-treatment (inactive phase) versus on-treatment (active phase). Outcomes were analysed by modified intention-to-treat. The study is registered with anzctr.org.au, ACTRN12622000634774 (not recruiting).

Findings: Forty participants were randomised (August 1, 2022 to December 16, 2024) and 38 included in the primary analysis (n = 6 female). A significant treatment by phase interaction effect (p < 0.001) was observed on self-reported pain. Pairwise comparison showed lower pain intensity during the active phase with CBD (mean ± SEM: 3.82 ± 0.23) compared to placebo (mean difference = -0.54, SEM = 0.15, p < 0.001), with a 95% confidence interval for the difference of -0.88 to -0.21. Treatments did not differ during the inactive phase (mean difference <0.01, SEM = 0.17, p = 1.00, 95% CI = -0.38 to 0.38). Adverse events, nearly all minor, were reported by 68.4% of participants during CBD (n = 67 events), and by 52.6% during placebo (n = 51 events) treatment.

Interpretation: In this placebo-controlled trial, CBD significantly reduced the self-reported intensity of neuropathic pain and was generally well-tolerated. While modest in magnitude, the observed effect supports further research into high-dose CBD for chronic neuropathic pain.”

https://pubmed.ncbi.nlm.nih.gov/42256679

“This trial provides evidence that high-dose CBD is safe and effective in treating chronic neuropathic pain following SCI. Additionally, the study provides initial evidence of a subgroup effect, whereby CBD is more effective in some individuals than others: this also warrants further exploration.”

https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(26)00234-8/fulltext

UK Medical Cannabis Registry: an updated analysis of clinical outcomes of medicinal cannabis therapy for hypermobility-associated chronic pain


“Introduction/objective: 
The primary aim of this study was to evaluate changes in pain-specific and general health-related quality of life in individuals prescribed cannabis-based medicinal products (CBMPs) for hypermobility-associated chronic pain.

Methods: The case series utilised data from the UK Medical Cannabis Registry. Primary outcomes were changes in Brief Pain Inventory (BPI), Pain Visual Analogue Scale (VAS), Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2), EQ-5D-5L index value, Generalised Anxiety Disorder-7 (GAD-7), and Single-item Sleep Quality Scale (SQS) over 24 months. Repeated measures analysis of variance was used to assess changes over time, with post hoc pairwise comparisons performed for significant findings.

Results: A total of 240 patients were analysed. Changes were observed across all patient-reported outcome measures (PROMs) on repeated measures analysis of variance (p < 0.001). Post hoc pairwise comparisons for the BPI subscales, SF-MPQ-2 and Pain VAS demonstrated improvement from baseline to all subsequent timepoints (p < 0.001). By 24 months, 56.67% (n = 136) and 61.25% (n = 147) of participants reported clinically significant improvements in BPI severity and interference respectively. Clinically significant improvements were also reported for SF-MPQ-2 (47.08%, n = 113) and Pain VAS scores (60.00%, n = 144).

Conclusion: In this real-world cohort, CBMP treatment was associated with sustained improvements in outcomes for individuals with hypermobility-associated chronic pain. These findings support the need for further controlled studies to determine causality.

Key Points • This 24-month real-world study demonstrates sustained improvements in pain, anxiety, and sleep outcomes for patients with hypermobility-associated chronic pain treated with cannabis-based medicinal products, with approximately 60% achieving clinically meaningful pain reductions.

• Cannabis-based medicinal products were associated with reductions in concomitant opioid prescriptions at 12, 18, and 24 months.

• This represents the largest and longest-duration observational study of medical cannabis therapy specifically in hypermobility spectrum disorders and Ehlers-Danlos syndrome, addressing a critical evidence gap in chronic pain management.

• Adverse events were predominantly mild-to-moderate in severity, with poor baseline sleep quality and current cannabis use identified as positive predictors of pain improvement, informing patient selection and treatment optimisation.”

https://pubmed.ncbi.nlm.nih.gov/42217098

“This study provides a 24-month real-world evaluation of CBMPs in patients with hypermobility-associated chronic pain. It demonstrates long-term sustained improvement in pain, anxiety and sleep-related outcomes, underpinning health-related quality of life. Despite its observational design, the study provides important insight into potentially addressing an area of significantly unmet therapeutic need.”

https://link.springer.com/article/10.1007/s10067-026-08166-z

Selective opioid-sparing effects of cannabidiol on opioid analgesia in rats

“Cannabidiol, a major non-psychoactive constituent of cannabis, has generated interest as a novel therapeutic for managing several pathological conditions including chronic pain and opioid use disorder.

Here, we evaluated the effects of cannabidiol (3.2 or 10.0 mg/kg) on the antinociceptive and the reward-related effects of the opioid analgesic oxycodone (0.56 mg/kg) in rats (male and female Sprague-Dawley) using an operant facial pain assay, locomotor activity monitoring, and the conditioned place preference paradigm.

Cannabidiol enhanced the antinociceptive effect of oxycodone without affecting oxycodone-induced rearing behavior, or the acquisition and expression of oxycodone conditioned place preference under the conditions tested.

Together, these findings suggest that cannabidiol potentiates the analgesic effects of oxycodone without affecting its reward-related properties. These results support the potential of cannabidiol as an adjunctive, opioid-sparing agent in pain management.

PERSPECTIVE: Opioids remain important for treating moderate to severe pain, but adverse effects and misuse liability limit their use. These preclinical findings suggest cannabidiol may enhance oxycodone antinociception under acute painful conditions, without increasing abuse-relevant effects under the conditions tested, supporting further study as an opioid-sparing adjunct.”

https://pubmed.ncbi.nlm.nih.gov/42219047

https://www.jpain.org/article/S1526-5900(26)00156-2/abstract

Endocannabinoid system modulation in acute, chronic, and neuropathic pain: reviewing experimental models, clinical evidence, and nanotechnology delivery

“Chronic pain is highly prevalent and inadequately managed by current therapeutic strategies, which present significant limitations such as the development of tolerance, dependence, and cognitive impairment. Therefore, searching for new pain management strategies is an ultimate goal.

The endocannabinoid system (ECS), is a broad crucial regulatory network in central nervous system’s development and in modulating various physiological and cognitive functions. It comprises endogenous cannabinoids, cannabinoid receptors, and the enzymes governing cannabinoid production and breakdown.

Recently, cannabinoids, particularly medical cannabis, have garnered renewed interest for their possibilities in treating different medical conditions, including chronic pain.

Although the risk of lethal overdose is negligible, the prevalence of non-serious adverse effects is significant and requires careful clinical consideration. Currently, there is a paucity of sufficient efficacy and long-term safety data to fully support the systematic use of medical cannabis for chronic non-malignant pain conditions.

Further research is crucial to unlock the future potential of these approaches and to delineate essential directions for exploring the ECS and its role in pain management. Advances in nanotechnology have enabled novel delivery platforms that address key limitations of cannabinoid-based therapies.

Nanocarriers, including lipid and polymeric nanoparticles, nanoemulsions, and self-emulsifying systems, can improve cannabinoid solubility, stability, bioavailability, and targeted delivery. Through controlled release and site-specific targeting, these systems hold promise for enhancing the analgesic efficacy and safety of cannabinoid therapeutics.”

https://pubmed.ncbi.nlm.nih.gov/42154330

https://link.springer.com/article/10.1007/s11011-026-01862-4