The Pharmacology of Cannabinoids in Chronic Pain

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“Background: Our objective was to provide an overview of the currently available scientific and clinical data supporting the use of Cannabis and Cannabis-derived products for the treatment of chronic pain disorders. We also provide information for researchers, clinicians, and patients to be better informed and understand the approach behind the recommendation of Cannabis as a potential adjuvant in the treatment/control of chronic pain. Cannabis and its bioactive compounds have sparked interest in the field of pain treatment in spite of its controversial history and status as a controlled substance in many countries. With the increase in chronic pain, physicians and patients have started to look at alternative ways to treat pain aside from traditional treatments. One alternative is the use of cannabis to reduce/treat chronic pain disorders based on anecdotal accounts and the function of its phytocannabinoids. The two main cannabinoids in cannabis, tetrahydrocannabinol (THC) and cannabidiol, act on CB1 and CB2 receptors (in addition to several additional receptors). It is through these pleiotropic receptor interactions that these compounds elicit their biological function including the reduction of chronic pain. In this narrative review, we included the most recent evidence supporting the use of cannabis in the treatment of chronic pain disorders including chronic neuropathic pain, cancer-induced neuropathic pain, chronic musculoskeletal pain, and chronic headaches and migraines.

Summary: Evidence suggests that cannabis and cannabinoids have an analgesic effect that arises from a combination of compounds and various receptor systems. These effects may be maximized with the use of a combination of cannabinoids. At the same time, the combination of cannabinoids helps minimize the undesirable side effects of some cannabinoids such as the psychoactivity of THC. With these findings, further research is necessary to assess the analgesic properties of other cannabinoids like cannabichromene and cannabigerol and their contributions to the reduction of pain.”

https://pubmed.ncbi.nlm.nih.gov/40046175/

“Cannabis sativa L. has been used as a medicinal remedy for thousands of years. It has gone through multiple periods of acceptance, dismissal/rejection, reacceptance, illegality and, most recently, rediscovery of its potential to address chronic medical conditions. In the last few decades, its recreational use has received growing acceptance, while its medical use has been encouraged in multiple jurisdictions. Most modern research has focused on the phytocannabinoids produced by the plant which have been found to help minimize chronic neuropathic pain and mitigate other disorders including seizure conditions (e.g., Lennox-Gastaut and Dravet syndromes) and spasticity in MS. This review has provided scientific evidence supporting the use of cannabis as an adjuvant in the treatment of chronic pain which could also lead pain reduction to the point of minimizing other pharmacological treatments.”

https://karger.com/mca/article/8/1/31/920366/The-Pharmacology-of-Cannabinoids-in-Chronic-Pain

“Designer cannabinoids could be the key to pain relief without adverse effects”

https://www.nature.com/articles/d41586-025-00546-w

A within-subject, double-blind, placebo-controlled randomized evaluation of the combined effects of cannabidiol and hydromorphone in a human laboratory pain model

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“Preclinical and epidemiological evidence supports that cannabinoids may have opioid-sparing properties and could be one strategy to decrease opioid use and associated harms like overdose and extramedical use.

The objective of this within subjects, double-blind, double-dummy, randomized human laboratory trial was to examine whether cannabidiol (CBD) increases opioid analgesic effects and whether there are corresponding increases in other opioid mediated effects.

Healthy participants (N = 31) attended 5 outpatient sessions where they received the following drug conditions: (1) placebo + placebo, (2) 4 mg hydromorphone + placebo, (3) 4 mg hydromorphone + 50 mg CBD, (4) 4 mg hydromorphone + 100 mg CBD, and (5) 4 mg hydromorphone + 200 mg CBD. Before and at multiple time points after drug administration, participants completed (1) quantitative sensory testing, which induced and assessed acute and chronic laboratory models of pain; (2) standard assessments, which queried acute subjective drug effects; and (3) tasks, which assessed psychomotor performance.

When combined with a dose of hydromorphone that did not reliably produce analgesic effects on its own, CBD increased the analgesic effects for some laboratory acute pain outcomes but none of the laboratory chronic pain outcomes. At the highest dose of CBD (200 mg), there were concurrent increases in self-report Bad Effects and adverse effects that were not observed at lower doses of CBD (50 mg). Cannabidiol mitigated psychomotor impairment observed with hydromorphone alone.

These findings suggest that lower doses of CBD (50 mg) may have utility for enhancing acute analgesic properties of opioids without having corresponding increases in bad effects.”

https://pubmed.ncbi.nlm.nih.gov/40035623/

https://journals.lww.com/pain/abstract/9900/a_within_subject,_double_blind,_placebo_controlled.840.aspx

Cannabis use and illicit opioid cessation among people who use drugs living with chronic pain

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“Introduction: Amidst the opioid overdose crisis, there is interest in cannabis use for pain management and harm reduction. We investigated the relationship between cannabis use and cessation of unregulated opioid use among people who use drugs (PWUD) living with chronic pain.

Method: Data for analyses were collected from three prospective cohort studies in Vancouver, Canada. All cohort participants who completed at least two study visits and reported both pain and unregulated opioid use in the past 6 months were included in the present study. We analysed the association between cannabis use frequency and opioid cessation rates using extended Cox regression models with time-updated covariates.

Results: Between June 2014 and May 2022, 2340 PWUD were initially recruited and of those 1242 PWUD reported chronic pain, use of unregulated opioids and completed at least two follow-up visits. Of these 1242 participants, 764 experienced a cessation event over 1038.2 person-years resulting in a cessation rate of 28.5 per 100 person-years (95% confidence interval [CI] 25.4-31.9). Daily cannabis use was positively associated with opioid cessation (adjusted hazard ratio 1.40, 95% CI 1.08-1.81; p = 0.011). In the sex-stratified sub-analyses, daily cannabis use was significantly associated with increased rates of opioid cessation among males (adjusted hazard ratio 1.50, 95% CI 1.09-2.08; p = 0.014).

Discussion and conclusions: Participants reporting daily cannabis use exhibited higher rates of cessation compared to less frequent users or non-users. Observed sex-specific differences in cannabis use and opioid cessation suggest potential differences in cannabis use behaviours and effects. Our findings add to the growing evidence supporting the potential benefits of cannabis use among PWUD, underlining the need for further research.”

https://pubmed.ncbi.nlm.nih.gov/40011075/

Pain Predicts Cannabis Initiation Among Emerging Adults: Results from the Population Assessment of Tobacco and Health (PATH) Study

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“Pain is highly prevalent among emerging adults (18-25 years old), and rates of cannabis use are increasing among this population. Research indicates pain is a unique risk factor and motivator for substance use. However, evidence for pain-cannabis use relations among emerging adults is largely cross-sectional, and the only prospective evidence focuses on the frequency, quantity, and consequences of cannabis use, not initiation.

Accordingly, this is the first study to examine pain as a prospective predictor of cannabis initiation among emerging adults.

Data were drawn from five annual waves of the Population Assessment of Tobacco and Health Study. Emerging adults who denied cannabis use at baseline (n = 4,185) were included in the analysis. At baseline, a tenth of emerging adults reported moderate/severe pain (≥4/10). Adjusted Cox regression analysis revealed that emerging adults with moderate/severe baseline pain were more likely to initiate cannabis use, and did so earlier over the subsequent 4 years, than those with no/low baseline pain.

These findings provide initial evidence for pain as a risk factor for cannabis initiation during emerging adulthood. Future research is needed to identify mechanisms by which pain motivates cannabis initiation and to examine the utility of pain-targeted content in cannabis use prevention and intervention efforts among emerging adults.”

https://pubmed.ncbi.nlm.nih.gov/40009033/

https://www.tandfonline.com/doi/full/10.1080/08964289.2025.2465525

Therapeutic potential of cannabinoids in neurological conditions: a systematic review of clinical trials

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“Overview: Cannabinoids have gained increasing attention for their therapeutic potential in treating several neurological conditions, including neurodegenerative diseases, chronic pain, and epilepsy. This review aims to assess the current clinical trials investigating cannabinoids, primarily Tetrahydrocannabinol and Cannabidiol, for neurological disorders. This review will aim to highlight the efficacy, safety, and outcome measures used in these trials.

Methods: Clinical trials were identified using ClinicalTrials.gov, focusing on studies that examined the effects of cannabinoids in treating neurological conditions. All trials that fulfilled the following criteria were included: Phase 1-4, focused on cannabinoids as primary intervention, and measured relevant outcomes such as pain relief, cognitive function, or spasticity reduction. Data on conditions, interventions, primary and secondary outcomes, and trial phases were extracted and analysed.

Results: A total of 47 clinical trials were identified, including different neurological conditions. The most frequently studied conditions were Multiple Sclerosis, Fibromyalgia, and Parkinson’s Disease. Most trials were in Phase 2, with the primary outcome measures focused on pain management, spasticity, and cognitive function. Secondary outcomes included safety and tolerability measures.

Conclusion: The review highlights the broad therapeutic potential of cannabinoids in neurology, with promising results in symptom management for conditions like Multiple Sclerosis and Fibromyalgia. However, the lack of standardized study protocols, dosing, and outcome measures presents challenges for broader clinical implementation.”

https://pubmed.ncbi.nlm.nih.gov/39981181/

“The results of this analysis showed that both CBD and THC have significant potential as therapeutic agents for neurological disorders, particularly in managing pain, motor dysfunction, and behavioural disturbances. However, their different pharmacological profiles and side effect risks mean that each cannabinoid may be better suited to different patient populations and conditions. While THC’s broader range of applications in cognitive and motor symptoms positions it as a more multipurpose treatment option, the psychoactive risks associated with its use should not be ignored. On the other hand, CBD’s safety and non-psychoactive nature make it more preferred option for managing chronic pain, but its therapeutic benefits may be more limited. Future research should focus on addressing the gaps in long-term safety and efficacy data, as well as exploring the full potential of lesser-known cannabinoids and combination therapies to further enhance the treatment of neurological disorders.”

https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2025.1521792/full

Medical Cannabis for Patients Over Age 50: A Multi-site, Prospective Study of Patterns of Use and Health Outcomes

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“Objective: Cannabis is being used as a therapeutic option by patients around the globe, and older patients represent a rapidly growing subset of this population. This study aims to assess the patterns of medical cannabis use in patients over 50 years of age and its effect on health outcomes such as pain, sleep, quality of life, and co-medication.

Method: The Medical Cannabis in Older Patients Study (MCOPS) is a multi-site, prospective observational study examining the real-world impact of medical cannabis use on patients over age 50 under the guidance of a health care provider. The study included validated instruments, with treating physicians collecting detailed data on participant characteristics, medical cannabis and co-medication use, and associated impacts on pain, sleep, quality of life, as well as adverse events.

Results: Inclusion criteria were met by 299 participants. Average age of participants was 66.7 years, and 66.2% of respondents identified as female. Approximately 90% of patients used medical cannabis to treat pain-related conditions such as chronic pain and arthritis. Almost all patients reported a preference for oral cannabis products (e.g., extracts, edibles) rather than inhalation products (e.g., flower, vapes), and most preferred oral formulations high in cannabidiol and low in tetrahydrocannabinol.

Over the six-month study period, significant improvements were noted in pain, sleep, and quality of life measures, with 45% experiencing a clinically meaningful improvement in pain interference and in sleep quality scores. Additionally, nearly 50% of patients taking co-medications at baseline had reduced their use by the end of the study period, and quality of life improved significantly from baseline to M3 and from baseline to M6, with an incremental cost per quality-adjusted life-year (QALY) of $25,357.20. No serious adverse events (SAEs) were reported.

Conclusions: In this cohort of older patients, most of whom suffered from pain-related conditions, medical cannabis seemed to be a safe and effective treatment. Most patients experienced clinically significant improvements in pain, sleep, and quality of life and reductions in co-medication. The cost per QALY was well below the standard for traditional pharmaceuticals, and no SAEs were reported, suggesting that cannabis is a relatively safe and cost-effective therapeutic option for adults dealing with age-related health conditions.”

https://pubmed.ncbi.nlm.nih.gov/39968489/

https://publications.sciences.ucf.edu/cannabis/index.php/Cannabis/article/view/239

Recreational Cannabis Laws and Fills of Pain Prescriptions in the Privately Insured

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“Objective: Almost half of U.S. states have passed recreational cannabis laws as of May 2024. While considerable evidence to date indicates cannabis may be a substitute for prescription opioids in the treatment of pain, it remains unclear if patients are treating pain with cannabis alone or concomitantly with other medications.

Method: Using data from a national sample of commercially insured adults, we examine the effect of recreational cannabis legalization (through two sequential policies) on prescribing of opioids, NSAIDS, and other pain medications by implementing synthetic control estimations and constructing case-study level counterfactuals for the years 2007-2020.

Results: Overall, we find recreational cannabis legalization is associated with a decrease in opioid fills among commercially insured adults in the U.S., and we find evidence of a compositional change in prescriptions of pain medications more broadly. Specifically, we find marginally significant increases in prescribing of non-opioid pain medications after recreational cannabis becomes legal in some states. Once recreational cannabis dispensaries open, we find statistically significant decreases in the rate of opioid prescriptions (13% reduction from baseline, p < .05) and marginally significant decreases in the average daily supply of opioids (6.3% decrease, p < .10) and number of opioid prescriptions per patient (3.5% decrease, p < .10).

Conclusions: These results suggest that substitution of cannabis for traditional pain medications increases as the availability of recreational cannabis increases. There appears to be a small shift once recreational cannabis becomes legal, but we see stronger results once users can purchase cannabis at recreational dispensaries. The decrease in opioids and marginal increase in non-opioid pain medication may reflect patients substituting opioids with cannabis and non-opioid pain medications, either separately or concomitantly. Reductions in opioid prescription fills stemming from recreational cannabis legalization may prevent exposure to opioids in patients with pain and lead to decreases in the number of new opioid users, rates of opioid use disorder, and related harms.”

https://pubmed.ncbi.nlm.nih.gov/39968486/

https://publications.sciences.ucf.edu/cannabis/index.php/Cannabis/article/view/268

Moroccan Cannabis sativa essential oil attenuates peripheral neuropathic pain induced by chronic sciatic nerve constriction injury in mice

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“Ethnopharmacological relevance: Cannabis sativa has been widely used in traditional medicine for its therapeutic properties. However, in Morocco, the ethnobotanical applications of Cannabis sativa, especially its essential oils, are underexplored. This study investigates, for the first time, the effects of Moroccan Cannabis sativa essential oil on peripheral neuropathic pain.

Materials and methods: Peripheral neuropathic pain was induced in mice through sciatic nerve injury. The mice were treated daily with cannabis essential oil for 21 days. Behavioral tests were conducted on days 1, 7, 14, and 21 to evaluate thermal, mechanical, and cold sensitivity. The essential oil’s chemical composition was analyzed using gas chromatography-mass spectrometry (GC/MS).

Results: The main constituents of the essential oil were (E)-caryophyllene (41.59%) and α-humulene (14%). Daily treatment with the essential oil significantly reduced pain sensitivity and improved functional and histological recovery over time. These effects are linked to the activity of the dominant terpenoids in the oil.

Conclusion: Moroccan Cannabis sativa essential oil shows significant therapeutic potential for managing peripheral neuropathic pain. By enhancing recovery and alleviating pain symptoms, it offers a promising alternative for treating chronic pain caused by nerve injuries.”

https://pubmed.ncbi.nlm.nih.gov/39947371/

“A multitude of recent studies have explored the broad biological properties of cannabis. Extracts from Cannabis sativa have demonstrated antimicrobial, anti-inflammatory, antinociceptive, and potent antioxidant activities.”

“This study examined the analgesic effects of terpenes found in Cannabis sativa essential oil on neuropathy. The results showed that chronic administration of these bioactive terpenes, specifically β-caryophyllene, α-humulene, and caryophyllene oxide, significantly increased pain sensitivity and response time in mice with neuropathy. Although morphine and THC-based treatments are commonly used to relieve neuropathic pain, these terpenes may offer a promising alternative with limited side effects. Clinical research has demonstrated the efficacy of cannabis-based treatments, leading several pain societies to recommend them for neuropathy management. “

https://www.sciencedirect.com/science/article/pii/S0378874125001692?via%3Dihub

The cannabinoid CB2 receptor mediates the analgesic effects of Cannabis sativa extract in a rat model of neuropathic pain

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“Neuropathic pain (NP) is a complex and debilitating condition that is often refractory to currently available analgesic medications.

Cannabis sativa extract (CSE) has been reported to exhibit analgesic properties across various pain models; however, the underlying mechanisms of action are not fully understood.

This study aimed to investigate the involvement of the cannabinoid CB2 receptor in mediating the analgesic effects of CSE in a rat model of NP, where NP was induced in male Wistar rats through chronic constriction injury (CCI) of the sciatic nerve.

Rats were randomly allocated into four groups: (1) Sham + vehicle, (2) CCI + vehicle, (3) CCI + CSE, and (4) CCI + CSE + AM630 (a CB2 receptor antagonist). CSE was administered intraperitoneally at a dosage of 30mg/kg once daily for 7 days, starting from day 7 to day 13 post-CCI surgery. To assess the involvement of the CB2 receptor, 7µg of AM630 was administered intrathecally to the rats in group 4, 30minutes before the CSE injections. Mechanical allodynia and thermal hyperalgesia were assessed using the von Frey filament and hot plate tests, respectively, at baseline (day 0) and on days 3, 7, 10, and 14 after surgery. Additionally, at the end of the study period (day 14), the expression level of Iba1 and GFAP genes was quantified in the lumbar enlargement tissues using real-time PCR.

The results demonstrated that CCI surgery induced mechanical allodynia and thermal hyperalgesia, along with the upregulation of Iba1 and GFAP genes in the vehicle-treated CCI group. Treatment with CSE significantly mitigated both allodynia and hyperalgesia and downregulated the expression of Iba1 and GFAP genes compared to the CCI + vehicle group. Furthermore, the administration of the CB2 receptor antagonist AM630 not only robustly blocked the antinociceptive effects of CSE but also reversed the significant downregulation of Iba1 and GFAP gene expression in the lumbar enlargement tissues.

These findings highlight the novel role of the CB2 receptor in mediating the analgesic effects of CSE, providing new insights into the potential therapeutic mechanisms of CSE in neuropathic pain management.”

https://pubmed.ncbi.nlm.nih.gov/39947333/

“In summary, this study provides evidence that CSE exerts analgesic and anti-inflammatory effects in NP through CB2 receptor activation. These findings contribute to the growing body of research supporting cannabinoids as potential therapeutic agents for NP management.”

https://www.sciencedirect.com/science/article/abs/pii/S0166432825000683?via%3Dihub

Entourage effects of nonpsychotropic cannabinoids on visceral sensitivity in experimental colitis

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“Abdominal pain is the most disabling symptom of inflammatory bowel diseases, but current treatments are limited, leading patients to seek alternatives such as cannabis.

Cannabis contains over 100 cannabinoids which, unlike tetrahydrocannabinol, are biologically active compounds often without psychotropic effects (ie, nonpsychotropic cannabinoids [npCBs]). These npCBs have analgesic and anti-inflammatory properties and may show potentiating effects when administered in combination, referred to as the entourage effect.

Here, we investigated the analgesic effects of cannabichromene, cannabidiol (CBD), cannabidivarin, and cannabigerol (CBG), individually and in combination, using the mouse model of dextran sulfate sodium colitis-induced visceral hypersensitivity (VHS).

We then explored antinociceptive targets through patch-clamp electrophysiology on dorsal root ganglia neurons and recombinant channels. We found that a single injection of 10 mg/kg of either CBD or CBG reduced both VHS and c-Fos activation in the spinal dorsal horn. Moreover, a combination of npCBs consisting of 5 mg/kg CBD with 1 mg/kg of cannabichromene, cannabidivarin, and CBG-all at subtherapeutic dosages-reduced VHS, without altering colitis. Electrophysiological recordings revealed that the antinociceptive mixture of npCBs acts through voltage-gated sodium and calcium channels, particularly Cav2.2, but not Cav3.2 and Kv channels.

These results suggest that CBD, CBG, and a mixture of npCBs given at subtherapeutic doses may be beneficial in managing VHS associated with inflammatory bowel disease.

SIGNIFICANCE STATEMENT: Cannabis is increasingly used as an alternative treatment for managing pain associated with chronic conditions. Nonpsychotropic cannabinoids, such as cannabidiol, interact with ionotropic and voltage-gated ion channels. In our study, we demonstrated that cannabidiol, cannabigerol, and a combination of nonpsychotropic cannabinoids, administered at subtherapeutic doses, effectively alleviated visceral hypersensitivity associated with inflammatory bowel disease.”

https://pubmed.ncbi.nlm.nih.gov/39921943/

https://jpet.aspetjournals.org/article/S0022-3565(25)09725-3/abstract