Evaluation of efficacy and safety of lubiprostone in patients with chronic constipation

Effectiveness and safety of lubiprostone after switching from stimulant laxatives in elderly patients with chronic constipation

Background and Aim

Stimulant laxatives may cause electrolyte abnormalities, dehydration, and abdominal pain; their long-term use can lead to tolerance and subsequent refractory constipation. We investigated the effectiveness, safety, and quality of life after switching from stimulant laxatives to lubiprostone in elderly patients with chronic constipation (CC).

Methods

This multicenter, interventional, open-label, single-arm, before-and-after comparison study enrolled 99 Japanese patients aged 65-90 years with CC who took stimulant laxatives for ≥2 weeks prior to switching to lubiprostone monotherapy.

Results

The mean ± SD spontaneous defecations at Week 1 of 7.8 ± 6.2 times/week was not significantly different from that at baseline (8.3 ± 4.7). Spontaneous defecations were significantly reduced at Weeks 2 (-1.5 ± 4.0, P < 0.001) and 4 (-1.5 ± 3.7, P < 0.001). The Bristol Stool Form Scale score did not change from baseline (4.7 ± 0.9) at Weeks 1 (4.5 ± 1.3) or 4 (4.3 ± 1.3), but it did at Week 2 (4.3 ± 1.5, P < 0.05). The Patient Assessment of Constipation Quality of Life questionnaire score increased (0.36 ± 0.07, P < 0.001) after 28 days. Nausea was the only symptom that worsened from baseline and was the most frequently reported adverse drug reaction (15.2%).

Conclusion

Switching to lubiprostone monotherapy for CC was not associated with significant concerns in short-term spontaneous defecation frequency and safety, but it might affect the efficacy and patient quality of life over 2 weeks. Careful treatment strategies facilitating gradual switching to lubiprostone monotherapy may be needed in patients using stimulant laxatives.

Pharmacokinetics and Bioequivalence of the Lubiprostone Capsule in Healthy Chinese Subjects

A pharmacokinetic (PK) study and a bioequivalence (BE) study were conducted to investigate the PK characteristics and safety of lubiprostone in healthy Chinese subjects and to evaluate the BE between the test and the reference drugs. The PK study consisted of a fasting state cohort (a single dose of 24 µg of lubiprostone), a 2-period crossover fasting and fed state cohort (a single dose of 48 µg of lubiprostone), and a multiple-dose cohort (24 µg of lubiprostone twice daily). The BE study was a single-dose, 2-treatment, 4-period, replicated crossover study. The plasma concentration of 15-OH-lubiprostone (M3) was measured by high-performance liquid chromatography-tandem mass spectrometry. The PK parameters were calculated using the noncompartment model with Phoenix WinNonlin. After a single dose of 24 ug of lubiprostone, the main PK parameters of M3 were 49.2 pg/mL, 74.0 h/pg/mL, and 1.1 hours for maximum plasma concentration (C_max ), area under the plasma concentration time curve from time 0 to the last time point, and t_1/2 , respectively. The main PK parameters of M3 showed dose-proportional characteristics in the dose range of 24-48 µg. Food affects the PK parameters of M3. Compared to the fasting state, time to maximum plasma concentration was delayed, C_max decreased slightly, while AUC increased significantly under the fed state. The test and reference products had similar PK parameters and were bioequivalent in the fed state.