Reconsolidation Blockade with Propranolol as a Novel Treatment for Chronic Low-Back Pain: A Double-Blind Randomized Placebo-Controlled Feasibility Study

Purpose: Nociplastic pain is often characterized by maladaptive plasticity in the nervous system similar to that observed in patients with post-traumatic stress disorder (PTSD). The aim of this study was to investigate whether reconsolidation therapy, a treatment for PTSD consisting in reactivating (through trauma narrative) the synapses encoding the excessive threat response and blocking their reconsolidation using propranolol, is feasible in patients with nociplastic low-back pain. Patients and Methods: Design: triple-blind, placebo-controlled feasibility study. Population: 24 adults with chronic (> 6 months) nociplastic low-back pain with no comorbid PTSD or contra-indication to propranolol. Intervention: Pain education (10 short videos) and 6 weekly sessions of reconsolidation therapy with propranolol (n=12) or placebo (n=12) administered orally 1h pre-reactivation. Outcome measures: Feasibility: recruitment rates, adverse events (frequency/severity). Effect of intervention: Brief Pain Inventory (BPI) and other self-reported pain questionnaires, 4 weeks post-intervention. Results: Sixty-six patients were screened over 6 months; 24 participants were enrolled; 2 dropped out. Adverse events were mild and infrequent (asymptomatic decrease in heart rate (n=4), headache and nausea (n=1)). No clinically meaningful difference was observed between the two groups on the pain questionnaires at the 4-week follow-up. Prevalent catastrophic/kinesiophobic discourse was noted during the sessions, and the reactivation methods appeared to have been suboptimal for the population. Conclusion: Reconsolidation therapy is a feasible intervention for chronic pain. Preliminary results suggest no effect on pain symptoms. Additional studies are warranted to assess the adequacy of reactivation procedures (proper reactivation being required to trigger reconsolidation), and to investigate whether the absence of negative pain beliefs might be a prerequisite (unmet in this study) for the success of the intervention. Keywords: reconsolidation therapy, nociplastic pain, post-traumatic stress disorder, amygdala