Medical cannabis for chronic non-cancer pain: A practical guide for doctors

Published: September 2025

Introduction

Chronic non-cancer pain (CNCP) remains one of the most significant challenges in Australian healthcare with one in five Australians experiencing chronic pain.^1,2

Historically defined as continuous or recurrent pain that persists for a period of longer than three months ^2,3, CNCP is a persistent, multifactorial condition arising from diverse pathophysiological mechanisms and shaped by cultural, psychological, and individual experience.²

It is estimated that between 20 and 40% of patient presentations to general practitioners involve chronic pain, making it one of the most common conditions encountered in primary care.² Data from the Bettering Evaluation and Care of Health (BEACH) initiative has shown that most presentations of CNCP relate to musculoskeletal conditions such as osteoarthritis and lower back pain, however one in five presentations is neurological.²

Beyond the individual burden, CNCP has a broader societal impact, contributing to disability, unemployment, and significant healthcare costs.^1,3-5

Standard pharmacological approaches - including paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), anticonvulsants, antidepressants, and particularly opioids - often fail to provide adequate long-term relief. ^2,5,6

Opioids remain widely prescribed, but evidence for their long-term benefit in CNCP is limited, while risks of dependence, tolerance, overdose, and death are well established.^4,7 Non-drug approaches such as physiotherapy and psychological interventions play important roles but are not universally effective.⁸ Against this backdrop, medical cannabis (MC) has emerged as a therapy of growing interest, offering an adjunctive option for patients who have exhausted conventional treatments.^3,5

Evidence for efficacy

Evidence supporting medical cannabis in CNCP, whilst limited, is steadily accumulating.^3,5 It is theorised that the key active cannabinoids in MC exert complementary analgesic and anti-inflammatory actions: tetrahydrocannabinol (THC) by blocking nociceptive stimuli, and cannabidiol (CBD) by exerting anti-inflammatory and calming effects.³

A 2017 meta-analysis by the Therapeutic Goods Administration (TGA) concluded that medical cannabis was more likely than placebo to produce reductions in pain intensity and to achieve clinically meaningful improvements of 30–50% in pain scores.^5,9

While there remains a lack of large randomised controlled trials (RCTs) investigating MC in CNCP, real-world evidence from large cohorts has contributed to the overall body of evidence:

However, the evidence is not uniformly positive. Some trials have failed to demonstrate the benefit of MC in CNCP. De Vries et al., in a placebo-controlled trial of THC tablets for chronic abdominal pain, found no difference in pain reduction between active treatment and placebo.¹⁴ Similarly, Campbell and colleagues, in a study of patients using illicit cannabis in conjunction with prescribed opioids, found no evidence of improved outcomes or reduced opioid use.¹⁵ Although this data was collected over a four-year period, the lack of guidance from medical practitioners on optimal use of cannabis for CNCP could have contributed to less than optimal outcomes.¹⁵

Interestingly, a number of studies reported an opioid sparing effect in subjects who took medically prescribed cannabis concomitantly with opioid therapy.^3,5,12

Taken together, the evidence base suggests that while medical cannabis is not universally effective in CNCP, it could offer benefit for some patients when used as part of an integrative approach.⁵

Limitations of the evidence

Despite promising findings, limitations remain. The majority of positive evidence comes from longer-term large observational and real-world studies, however they are highly heterogeneous in terms of formulation composition, cannabinoid ratios, and delivery methods, whilst the lack of placebo controls may lead to overestimation of MC’s benefits.³

Safety and tolerability

As with any therapy, safety is a key consideration. Across clinical trials and observational studies, the most frequently reported adverse effects included fatigue, somnolence, dizziness, cognitive impairment, dry mouth, gastrointestinal upset, and increased appetite. ³ Severe adverse events are rare but do occur, including hallucinations, dysphoria, and cardiovascular complications.³

Long-term safety data remain limited, although recent large-scale studies demonstrated that over 1-2 years of MC treatment, adverse effects, while frequent, were generally mild in nature.^10,13 Nevertheless, caution should be exercised in vulnerable populations (see Patient Selection below).

Patient selection

Deciding which patients are appropriate candidates for medical cannabis is central to safe and effective prescribing.¹⁶ MC may not be suitable for all patients with CNCP, and careful consideration of risks, benefits, and alternatives is essential.

Additionally, caution is advised in patients with a personal or family history of psychosis, those with unstable cardiovascular disease, and younger adults under the age of 25, due to neurodevelopmental concerns. Pregnant and breastfeeding women should also avoid cannabinoid therapy.^3,16,17

Administering medical cannabis in CNCP

Beyond the general TGA "Guidance for the use of medicinal cannabis in Australia”, which recommends a ‘start low go slow’ approach to MC dose titration¹⁶, there are few guidelines for the dosing and titration of MC in CNCP. A recent consensus-based review sought to define dosing and titration protocols for oral MC in CNCP. The consensus of twenty global experts across nine countries developed three such treatment protocols based on patient factors such as susceptibility to MC, adverse effects and prior cannabis use history:

• Routine protocol - recommended for most patients (unless sensitive to MC or requiring rapid pain relief).¹⁷

*Refer for expert consultation if considering >40 mg/day THC
(Adapted from Bhaskar et al. 2021)

• Conservative protocol - recommended for patients more sensitive to MC’s effects (e.g.frail, complex co-morbidities).¹⁷

*Refer for expert consultation if considering >40 mg/day THC
(Adapted from Bhaskar et al. 2021)

• Rapid protocol - recommended for patients in severe pain, requiring palliation, or with a significant history of prior cannabis use.¹⁷

*Refer for expert consultation if considering >40 mg/day THC
(Adapted from Bhaskar et al. 2021)

• Breakthrough pain - The authors also made provision for the use of inhaled dried flower MC (either balanced THC:CBD or THC dominant) to be considered for patients experiencing breakthrough pain.¹⁷

Integrating medical cannabis into multimodal pain care

Medical cannabis should not be viewed as a standalone therapy but as one element of a multimodal pain management plan.^1,5 Comprehensive care should incorporate physiotherapy, cognitive behavioural therapy, lifestyle modifications, and social support alongside pharmacological measures.^1,5 Within this framework, MC may provide incremental improvements in pain relief, mood, sleep, and overall quality of life, enhancing the effectiveness of other interventions.^3,5

Summary

Medical cannabis represents an emerging option for the management of chronic non-cancer pain.^3,5 While it is not a panacea, evidence suggests that it may provide meaningful improvements in pain, quality of life, and function for selected patients, with an acceptable safety profile.^510,13 For some patients, it may reduce reliance on opioids and other medications, and may offer a safer long-term alternative.^3,5,12

Prescribers should approach cannabis with the same clinical rigour as any other therapy: starting with careful patient selection, initiating treatment at low doses, monitoring closely, and discontinuing if ineffective.¹⁵ When integrated into a multimodal pain management strategy, MC has the potential to enhance outcomes and provide relief for patients whose options have been limited.⁵

As research expands, doctors may gain greater clarity on optimal formulations, dosing strategies, and long-term outcomes. In the meantime, thoughtful, evidence-informed prescribing may help patients achieve the desired benefit from this evolving therapeutic tool.

Disclaimer: Medical cannabis products may be associated with adverse events. For more information please contact medinfo@saged.com.au. Medical cannabis products are not suitable for use during pregnancy or breastfeeding, for anyone with a history with psychotic disorders, or for those with unstable cardiovascular disease. Treatment for patients under 18 years is recommended under the guidance of a paediatrician. Patients should not drive or operate machinery while being treated with some forms of medical cannabis.