Efficacy and safety of pregabalin in patients with neuropathic cancer pain undergoing morphine therapy.

OBJECTIVE

To evaluate the efficacy and the safety of pregabalin (PGB)-morphine combination for the treatment of neuropathic cancer pain (NCP).

METHODS

In this double-blind, randomized, placebo (PL)-controlled crossover study, 40 cancer patients with severe NCP were randomized into two groups (20 per group): PGB-PL and PL-PGB. Patients in the PGB-PL group received PGB plus oral morphine in phase I, and PL plus oral morphine in phase II. The treatment sequence for the PL-PGB group was PL plus oral morphine in phase I, and PGB plus oral morphine in phase II. These 2-week treatment periods were separated by a 1-week washout period. The primary outcome measure was the decrements in morphine dose; secondary outcomes included quantitative assessments of sleep (rated according to the Medical Outcomes Study Sleep Scale), the Constipation Assessment Scale and adverse effects.

RESULTS

The mean minimal effective dose of morphine was 184.4 ± 69.9 mg/day in the period of PGB treatments, which was significantly lower than that of PL-controls (228.7 ± 66.9 mg/day; P < 0.001) and baseline (247.5 ± 80.0 mg/day; P < 0.001). Compared with PL, PGB resulted in a significant sleep improvement as measured by sleep disturbance, sleep quantity, and sleep problems index (P < 0.001), as well as a Constipation Assessment Scale reduction (P < 0.001). PGB resulted in a higher frequency of dry mouth and somnolence than PL (P < 0.05).

CONCLUSIONS

PGB enhances the efficacy of oral morphine and reduces dose-related adverse reactions. The PGB-morphine combination is an effective approach to controlling NCP.