Low-dose gabapentin as useful adjuvant to opioids for neuropathic cancer pain when combined with low-dose imipramine

Painful neuropathic conditions of cancer pain often show little response to nonopioid and opioid analgesics but may be eased by antidepressants and anticonvulsants. Although gabapentin is effective in the treatment of neuropathic pain in patients with cancer, some patients experience intolerable side effects sufficient to warrant discontinuation. The aim of this study was to see whether low-dose gabapentin is effective in treating cancer-related neuropathic pain when combined with low-dose imipramine. Fifty-two cancer patients diagnosed as having neuropathic pain were allocated into four groups: G400-I group took gabapentin 200 mg and imipramine 10 mg every 12 h orally; G400 group took gabapentin 200 mg every 12 h orally; G800 group took gabapentin 400 mg every 12 h orally; I group took imipramine 10 mg every 12 h orally. Low-dose gabapentin-imipramine significantly decreased the total pain score and daily paroxysmal pain episodes. Several patients developed mild adverse symptoms in the four groups, and three patients discontinued treatment due to severe adverse events in the G800 group. Low-dose gabapentin-antidepressant combination with opioids was effective in managing neuropathic cancer pain without severe adverse effects.