- Oral methylnaltrexone (Relistor) was effective at reducing opioid-induced constipation (OIC) in patients with chronic noncancer pain, with fewer treatment-emergent adverse events (TEAEs) and no evidence of opioid withdrawal symptoms compared with placebo.
Why this matters
- This study offers a detailed safety analysis of oral methylnaltrexone based on the phase 3 trial that led to its FDA approval.
- 41% of people with chronic noncancer pain experience OIC.
- 803 adults with chronic noncancer pain for ≥2 months and confirmed OIC who received opioids for ≥1 month (≥50 mg morphine equivalent/day) were evaluated.
- Patients were randomly allocated to 1:1:1:1 placebo or oral methylnaltrexone 150, 300, or 450 mg/day for 4 weeks.
- Objective opioid withdrawal scale (OOWS) and subjective opioid withdrawal scale (SOWS) assessed opioid withdrawal.
- Funding: Salix Pharmaceuticals.
- TEAEs occurred in 59.0% vs 63.0% patients receiving methylnaltrexone vs placebo.
- Cardiac TEAEs occurred in 1.8% vs 1.0% in methylnaltrexone vs placebo groups, and none led to treatment discontinuation.
- Rescue laxative use was more common with placebo (6.20% of study days) vs methylnaltrexone 150, 300, and 450 mg (5.78%, 5.14%, and 4.27% of study days, respectively; P=.024) groups.
- Changes in OOWS, SOWS, and pain-intensity scores were minimal.
- Secondary analysis.
Coauthored with Antara Ghosh, PhD