Gabapentin monotherapy for the treatment of chemotherapy-induced neuropathic pain: a pilot study.

Objective: This study was conducted to investigate the efficacy and safety of gabapentin monotherapy in the management of chemotherapy-induced neuropathic pain.

Patients: Seventy-five cancer patients who had previously received chemotherapy, and had experienced at least one symptom of neuropathic pain were included in the intervention group. They received a fixed low-dose of gabapentin (800 mg/day). The control group consisted of 35 cancer patients with similar treatment history and symptomatology, who refused treatment with gabapentin and, therefore, received a fixed-dose combination of naproxen and codeine/paracetamol.

Outcome Measures: Patients were grouped in three categories according to the severity of their neuropathic symptoms at baseline: mild, moderate, and severe. Analgesic efficacy of the study drug was assessed by means of a patient-answered questionnaire. Four stages of analgesic response were established: complete, partial, minor, and no response.

Results: All patients completed the study and were evaluable. In the intervention arm, gabapentin led to a complete response in 25.3% of patients (19/75), partial response in 44% (33/75), minor response in 25.3% (19/75), and no response in 5.3% (4/75). The response to gabapentin correlated with the severity of the underlying neurotoxicity. Approximately 25% of patients receiving gabapentin experienced mild somnolence, but none discontinued it. In the control group, none experienced complete response (0/35), while partial, minor, and no response were observed in 5.7% (2/35), 45.7% (16/35), and 48.6% (17/35), respectively. Compared with the control group, gabapentin therapy led to a statistically significant better response in patients of each baseline neurotoxicity group.

Conclusions: Gabapentin monotherapy seems to be well tolerated and useful for the management of chemotherapy-induced neuropathic pain.