Baclofen as an adjuvant analgesic for cancer pain.

PURPOSE Baclofen is a g-aminobutyric acid receptor agonist commonly used for managing many types of neuropathic pain. The effect of baclofen on cancer pain has not previously been studied. This retrospective study evaluated the efficacy of baclofen in patients with cancer pain. METHODS We reviewed the medical records of all patients given baclofen orally as an analgesic for cancer at 5 institutions. RESULT Twenty-five patients received 10 to 40 mg of baclofen for cancer pain relief. Twenty patients have undergone neuropathic pain such as paroxysmal or lancing, sharp, or like an electric shock. Baclofen was effective in 21 of 25 patients and significantly reduced Numeric Rating Scale (pain score, 0-10; P < .0001). Nine patients reported mild adverse events: none of these 9 patients had to discontinue baclofen due to adverse events. CONCLUSION Our findings suggest that baclofen may be a useful adjuvant analgesic in the treatment of cancer pain.