Placebo-controlled trial of lubiprostone for constipation associated with Parkinson disease

Objective: To evaluate the efficacy and tolerability of lubiprostone (Amitiza) for constipation in Parkinson disease (PD) in a double-blind, randomized, controlled study. Methods: Patients with PD and clinically meaningful constipation (constipation rating scale score > 10 [range: 0-28]) were recruited from 2 academic movement disorder centers to participate in the study. After enrollment, patients were initially followed for 2 weeks and then were randomly assigned 1:1 to lubiprostone, and the dose was titrated up to 48 >g/day. They returned 4 weeks later for a final assessment. Data included stool diaries and global impressions (coprimary endpoints), demographics, Unified Parkinson's Disease Rating Scale scores, constipation scale scores, visual analog scale (VAS) scores, a stool diary, and adverse events. Results: Fifty-four subjects (39 male, mean age 67.0 ± 10.1 years, and mean duration of PD 8.3 ± 5.4 years) were randomly assigned to lubiprostone or placebo. One patient in the drug group discontinued the study because of logistics, and one patient in the placebo group discontinued the study because of lack of efficacy. A marked or very marked clinical global improvement was reported by 16 of 25 (64.0%) subjects receiving drug vs 5 of 27 (18.5%) subjects receiving placebo (p lt;0.001). The constipation rating scale (p<0.05), VAS (p lt;0.001), and stools per day in the diary (p lt; 0.001) all improved with drug compared with placebo. Adverse events with drug were mild, most commonly intermittent loose stools. Conclusion: In this randomized controlled trial, lubiprostone seemed to be well tolerated and effective for the short-term treatment of constipation in PD. Level of Evidence: This study provides Class I evidence that lubiprostone improves constipation in PD over 4 weeks