2011/06/01 by Neil A. Hagen, Bernard Lapointe, May Ong-Lam +8 · 3 citations
Environmental Science · Medicine · #Marine Toxins and Detection Methods #Opioid Use Disorder Treatment #Pain Management and Opioid Use
paper · pdf · doi:10.3747/co.v18i3.732
openalex publication_date 2011/06/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
BACKGROUND: Cancer pain is highly prevalent, and existing treatments are often insufficient to provide adequate relief. OBJECTIVES: We assessed the long-term safety and efficacy of subcutaneous tetrodotoxin treatment in reducing the intensity of chronic cancer-related pain. METHODS: In this multicentre open-label longitudinal trial, 30 μg tetrodotoxin was administered subcutaneously twice daily for 4 days in a heterogeneous cohort of patients with persistent pain despite opioids and other analgesics. "Responder" was defined as a mean reduction of 30% or more in pain intensity from baseline; and "clinical responder" as some pain reduction, but less than 30%, plus agreement on the part of both the patient and the physician that a meaningful analgesic response to treatment had occurred. RESULTS: Of 45 patients who entered the longitudinal trial, 41 had sufficient data for analysis. Of all 45 patients, 21 (47%) met the criteria for "responder" [16 patients (36%)] or "clinical responder" [5 patients (11%)]. Onset of pain relief was typically cumulative over days, and after administration ended, the analgesic effect subsided over the course of a few weeks. No evidence of loss of analgesic effect was observed during subsequent treatments (2526 patient-days in total and a maximum of 400 days in 1 patient). One patient withdrew from the study because of adverse events. Toxicity was usually mild (82%) or moderate (13%), and remained so through subsequent treatment cycles, with no evidence of cumulative toxicity or tolerance. CONCLUSIONS: Long-term treatment with tetrodotoxin is associated with acceptable toxicity and, in a substantial minority of patients, resulted in a sustained analgesic effect. Further study of tetrodotoxin for moderate-to-severe cancer pain is warranted.