Can Cannabis Replace Opioids for Chronic Pain? A New Review Maps What We Know and What Remains Uncertain

A 2025 narrative review published in Stresses synthesizes mechanistic, clinical, and regulatory evidence on cannabinoids for chronic pain, finding biological plausibility and some clinical signal but identifying significant evidence gaps that preclude routine clinical adoption without further standardized trials.

Why This Matters

Chronic pain affects hundreds of millions of people worldwide and remains one of the most common reasons patients seek medical care. The well-documented limitations and risks of long-term opioid therapy have created urgent demand for credible alternatives, and cannabinoids have emerged as the most publicly visible candidate. Yet patient interest has consistently outpaced the evidence, leaving clinicians to navigate conversations about cannabis with limited rigorous data. A consolidated review of where the science actually stands, covering mechanisms, clinical findings, and regulatory barriers, is especially timely as more jurisdictions liberalize access to medical cannabis.

Clinical Summary

This 2025 narrative review by Paduraru and colleagues, published in Stresses (MDPI), surveys the current landscape of cannabinoid science as it applies to chronic pain management. The review covers the pharmacology of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), both of which interact with the endocannabinoid system through distinct pathways. THC acts as a partial agonist at CB1 and CB2 receptors, directly modulating nociceptive signaling but also producing psychoactive effects that limit tolerability. CBD, by contrast, does not directly activate cannabinoid receptors but exerts anti-inflammatory and neuromodulatory effects through TRPV1, serotonin receptors, and other targets. This multi-receptor pharmacology provides a plausible mechanistic rationale for pain modulation, supported by both preclinical data and some clinical observations.

The review reports that clinical evidence is most supportive for cannabinoid use in neuropathic pain, multiple sclerosis-related spasticity and pain, and certain arthritis subtypes, particularly in patients who have not responded to conventional treatments. However, because this is a narrative review rather than a systematic review or meta-analysis, it does not pool effect sizes, apply formal inclusion and exclusion criteria, or conduct risk-of-bias assessments of cited trials. The authors emphasize that major barriers to clinical integration remain unresolved: there is no consensus on standardized dosing, long-term safety data are sparse, psychiatric and cardiovascular adverse effects are real concerns, cytochrome P450-mediated drug interactions complicate polypharmacy, and regulatory frameworks vary dramatically across jurisdictions. The authors conclude that more rigorous, standardized clinical trials are needed before cannabinoids can be recommended as routine therapy for chronic pain.

Dr. Caplan’s Take

This review does a reasonable job of consolidating the mechanistic case for cannabinoid analgesia, and the biology is genuinely interesting. The endocannabinoid system is clearly involved in pain modulation, and the multi-target pharmacology of both THC and CBD makes a credible scientific argument. But when patients ask me whether cannabis can replace their pain medication, an honest answer requires distinguishing between biological plausibility and clinical proof. We do not yet have the kind of well-controlled, adequately powered trial data that would let me confidently prescribe cannabinoids as a frontline chronic pain treatment with predictable outcomes.

In practice, I discuss cannabinoids with chronic pain patients as one component of a broader integrative strategy, not as a standalone replacement for existing therapies. For patients interested in trying CBD or medical cannabis, I focus on starting low, titrating slowly, monitoring for drug interactions (especially in patients on anticoagulants, antiepileptics, or immunosuppressants), and setting realistic expectations. I also make sure patients understand that the regulatory product landscape is uneven and that what they purchase over the counter may not match what was studied in clinical trials. The science is moving in the right direction, but it has not arrived yet.

Clinical Perspective

This review sits at the exploratory end of the research arc. It consolidates known mechanisms and clinical observations but does not advance the evidence base through new data or rigorous evidence synthesis. For clinicians, its value lies in framing the current state of knowledge: cannabinoids have a plausible biological basis for pain modulation, and some clinical studies support their use in specific refractory pain conditions. However, the absence of systematic methodology in this review means its literature coverage may be incomplete or selectively favorable. The evidence does not yet support recommending cannabinoids as standard therapy for chronic pain in general clinical populations, and clinicians should be transparent with patients about this limitation.

From a pharmacological standpoint, both THC and CBD are substrates and inhibitors of cytochrome P450 enzymes, particularly CYP3A4 and CYP2C19, raising meaningful drug interaction concerns in patients on polypharmacy regimens. THC carries documented risks of anxiety, paranoia, cognitive impairment, and cardiovascular effects, while CBD, though better tolerated, can cause hepatotoxicity at higher doses and interacts with commonly prescribed medications including warfarin and clobazam. Clinicians should note that no FDA-approved cannabinoid product currently carries a chronic pain indication. The most actionable step for practitioners is to ensure that any patient-initiated cannabinoid use is documented, monitored for interactions, and evaluated against the patient’s complete medication profile.

Study at a Glance

Study Type

Narrative review

Population

Adults with chronic pain conditions (neuropathic, MS-related, arthritis, cancer pain); preclinical models also discussed

Intervention

Cannabinoids including delta-9-THC, CBD, and synthetic cannabinoids

Comparator

Not applicable (narrative review, no direct comparisons conducted)

Primary Outcomes

Pain modulation mechanisms, clinical efficacy patterns, safety and tolerability, regulatory barriers

Sample Size

Not applicable (review of existing literature)

Journal

Stresses (MDPI), open access

Year

2025

DOI

10.3390/stresses5010007

Funding Source

Not reported in the extracted text

What Kind of Evidence Is This

This is a narrative review, which occupies a lower tier of the evidence hierarchy compared to systematic reviews and meta-analyses. It synthesizes existing literature based on the authors’ expert reading but does not describe a reproducible search strategy, apply formal inclusion or exclusion criteria, or assess the risk of bias in cited studies. The most important inference constraint this imposes is that the review’s completeness and balance cannot be independently verified, and its conclusions should be understood as informed expert opinion rather than the output of a rigorous, unbiased evidence synthesis.

How This Fits With the Broader Literature

This review is broadly consistent with findings from more rigorous syntheses, including the 2017 National Academies report on cannabis and cannabinoids, which found substantial evidence for cannabinoid efficacy in chronic pain but called for better-designed trials. It also aligns with systematic reviews such as Whiting et al. (2015) in JAMA, which reported moderate-quality evidence supporting cannabinoids for chronic pain with a number needed to treat that, while encouraging, came with notable adverse effect rates. The current review extends these earlier works by incorporating more recent mechanistic insights and updated regulatory information, but it does not fundamentally challenge prior conclusions. The persistent theme across the literature remains one of biological promise constrained by clinical evidence that is insufficient in quality and quantity to support definitive treatment recommendations.

Common Misreadings

The most likely overinterpretation of this review is to read its mechanistic and clinical narrative as establishing that cannabinoids are a proven, effective treatment for chronic pain. The review uses language such as “can significantly reduce” pain intensity, but this reflects patterns observed in individual cited studies, not a quantified treatment effect derived from this review itself. Because no formal effect size pooling or quality assessment was conducted, readers cannot infer the magnitude or reliability of cannabinoid analgesia from this paper alone. Citing this review as evidence that cannabinoids should replace opioids or other conventional pain treatments would exceed what the data, as presented here, actually support.

Bottom Line

This narrative review provides a useful consolidated overview of the mechanistic rationale, clinical signals, and practical barriers surrounding cannabinoid use for chronic pain. It does not establish efficacy with the rigor required to change clinical practice. Cannabinoids remain a scientifically credible but clinically unproven option for chronic pain, and their integration into standard care awaits standardized dosing protocols, long-term safety data, and adequately powered randomized controlled trials.

References

1. Paduraru AM, et al. Medical cannabis and cannabinoids for chronic pain: mechanisms, therapeutic challenges, and future directions. Stresses. 2025;5(1):7. DOI: 10.3390/stresses5010007
2. National Academies of Sciences, Engineering, and Medicine. The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research. Washington, DC: The National Academies Press; 2017. DOI: 10.17226/24625
3. Whiting PF, Wolff RF, Deshpande S, et al. Cannabinoids for medical use: a systematic review and meta-analysis. JAMA. 2015;313(24):2456-2473. DOI: 10.1001/jama.2015.6358