Nerve blocks with 5% butamben suspension for the treatment of chronic pain syndromes

Background and Objectives. Butamben is a non-water-soluble local anesthetic that can be prepared as an aqueous suspension for nerve blocks. This report describes the use of 5% butamben suspension for the treatment of chronic pain of cancer and noncancer origin. Methods. The clinical courses of 75 consecutive patients were analyzed following 5% butamben nerve blocks (35 epidural blocks only, 33 peripheral nerve blocks only, and 7 had both epidural and peripheral nerve blocks). Epidural blocks were performed as a series of four with additional blocks offered if needed. Peripheral nerve blocks were done as a single block with repeat injections if needed. Injection volumes varied between 15 and 25 mL for epidural injections and 5 and 20 mL for peripheral nerve blocks. Successful therapy was defined as a ≤75% reduction in subjective pain assessments for ≤4 weeks or until death. Daily opioid requirements were also recorded. Results. Fifty-four of the 75 patients (72%) were successfully treated. This included 48 of 67 cancer patients (71.6%) and 6 of 8 noncancer patients (75%). Median duration of pain relief was 12 weeks (range, 1-96) in the cancer patients and 10 weeks (range, 6-166) in the noncancer patients. Mean reduction in opioid requirements in successfully treated cancer patients was 74 ± 5%. Pain on epidural injection occurred in half of the patients and was the most prevalent complication of treatment. Five patients had signs of intravascular injection. There were no serious long-term sequelae. Conclusions. When used as described in this report, 5% butamben suspension appears to be effective for treatment of chronic pain of both cancer and noncancer origin and has a low incidence of adverse sequelae.