“Background/Objectives: Diabetic neuropathy (DN) is a prevalent complication of diabetes mellitus, affecting up to 50% of long-term patients and causing significant pain, reduced quality of life, and healthcare burden. Conventional treatments, including anticonvulsants, antidepressants, and opioids, offer limited efficacy and are associated with adverse effects. Emerging evidence suggests that cannabis, acting via the endocannabinoid system, may provide analgesic and neuroprotective benefits. This study evaluates the long-term effects of inhaled cannabis as adjunctive therapy for refractory painful DN. Inhaled cannabis exhibits rapid onset pharmacokinetics (within minutes, lasting 2-4 h) due to pulmonary absorption, targeting CB1 and CB2 receptors to modulate pain and inflammation. 

Methods: In this prospective, observational study, 52 patients with confirmed painful DN, unresponsive to at least three prior analgesics plus non-pharmacological interventions, were recruited from a single clinic. Following a 1-month washout, patients initiated inhaled medical-grade cannabis (20% THC, <1% CBD), titrated individually. Assessments occurred at baseline and annually for 5 years, including the Brief Pain Inventory (BPI) for pain severity and interference; the degree of pain relief; Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) score; HbA1c; and medication usage. Statistical analyses used repeated-measures ANOVA, Kruskal-Wallis tests, Welch’s t-tests, and Pearson’s correlations via Analyze-it for Excel. 

Results: Of 52 patients (mean age 45.3 ± 17.8 years; 71.2% male; diabetes duration 23.3 ± 17.8 years), 50 completed follow-up visits. Significant reductions occurred in BPI pain severity (9.0 ± 0.8 to 2.0 ± 0.7, p < 0.001), interference (7.5 ± 1.7 to 2.2 ± 0.9, p < 0.001), LANSS score (19.4 ± 3.8 to 10.2 ± 6.4, p < 0.001), and HbA1c (9.77% ± 1.50 to 7.79% ± 1.51, p < 0.001). Analgesic use decreased markedly (e.g., morphine equivalents: 66.8 ± 49.2 mg to 4.5 ± 9.6 mg). Cannabis dose correlated positively with pain relief (r = 0.74, p < 0.001) and negatively with narcotic use (r = -0.43, p < 0.001) and pain interference (r = -0.43, p < 0.001). No serious adverse events were reported; mild side effects (e.g., dry mouth or euphoria) occurred in 15.4% of patients. 

Conclusions: Inhaled cannabis showed sustained pain relief, improved glycemic control, and opioid-sparing effects in refractory DN over 5 years, with a favorable safety profile. These findings are associative due to the observational design, and randomized controlled trials (RCTs) are needed to confirm efficacy and determine optimal usage, addressing limitations such as single-center bias and small sample size (n = 52). Future studies incorporating biomarker analysis (e.g., endocannabinoid levels) could elucidate mechanisms and enhance precision in cannabis therapy.”

https://pubmed.ncbi.nlm.nih.gov/41153689/

“Inhaled cannabis add-on therapy mitigated symptoms of diabetic neuropathy over the course of a five-year observation period. Some reduction in glycosylated hemoglobin is observed as well as major reduction in the need for other prescription medications, including opiates and opioids. It is possible to state the following: (1). Inhaled cannabis significantly reduced pain and neuropathic symptoms over 5 years. (2). It decreased opioid use, supporting an opioid-sparing effect. (3). HbA1c improvements suggest a metabolic benefit, though causality is unproven. (4). No serious adverse events occurred, with mild effects in 15.4% of patients. (5). RCTs are needed to confirm efficacy and address accessibility barriers. Integration of objective pain assessment tools, such as salivary biomarker devices, could enhance the precision and reproducibility of cannabis therapy outcomes in DN.”

https://www.mdpi.com/2227-9059/13/10/2406