The effect of intrathecal baclofen single injection on neuropathic pain

ABSTRACT

BACKGROUND: Baclofen is a gamma-aminobutyric acid B-receptor agonist, which is usually used for patients with spasticity or patients with nerve injury inducing both spasticity and neuropathic pain. Both oral administration and intrathecal injection via a continuous infusion pump are common treatment methods. The aim of this study was to evaluate the effectiveness of a series of three individual injections of intrathecal baclofen for neuropathic pain without spasticity. METHODS: Thirty-one patients with neuropathic pain were treated with a series of three monthly individual injections of intrathecal baclofen without pump implantation A dose of 50 µg of baclofen was used. 10-cm visual analog scale (VAS) scores of spontaneous pain, allodynia, and hyperalgesia were recorded a week after each injection. Vital signs were monitored to detect any hemodynamic changes, and a myelogram was performed to detect any undesirable cerebrospinal fluid leakage. All patients were hospitalized for at least one day following each injection for close observation and to control any adverse effects. RESULTS: VAS scores of spontaneous pain, allodynia, and hyperalgesia decreased significantly (P < 0.001). The major complications were general weakness, sleepiness, and urinary retention; most of these resolved within one day without any further serious symptoms. CONCLUSIONS: A series of three individual intrathecal baclofen injections was effective for those patients who suffered from neuropathic pain without spasticity or dystonia; no serious complications were observed. However, the average satisfaction score recorded for spontaneous pain was lower than those for allodynia and hyperalgesia.