Pregabalin in the treatment of refractory neuropathic pain: results of a 15-month open-label trial.

OBJECTIVE: Neuropathic pain associated with postherpetic neuralgia (PHN) and painful diabetic peripheral neuropathy (DPN) can be intractable and may not respond to commonly used treatments, such as tricyclic antidepressants (TCAs) and opioids. This long-term, open-label study was a preliminary evaluation of pregabalin for patients whose pain had been judged refractory to other treatments for neuropathic pain. DESIGN: Patients had previously participated in double-blind, placebo-controlled, randomized trials of pregabalin in DPN and PHN. They had moderate to severe neuropathic pain despite treatment with gabapentin, a TCA, and a third medication (e.g., other anticonvulsants, opioid, selective serotonin reuptake inhibitor, tramadol). Flexible-dosage pregabalin 150-600 mg/day was taken for 3-month periods followed by 3- to 28-day pregabalin "drug holidays," with an analysis up to 15 months (five treatment cycles). Pain intensity was measured using the visual analog scale of the Short-Form McGill Pain Questionnaire. RESULTS: In total, 81 patients were included in this analysis. Pregabalin 150-600 mg/day was associated with clinically meaningful and sustained pain reduction during each treatment cycle. During pregabalin "drug holidays," pain quickly returned to baseline levels; it was reduced again when pregabalin was reinstated. CONCLUSIONS: These results suggest that pregabalin may be beneficial in patients with neuropathic pain who have had an unsatisfactory response to treatment with other medications.