Nalamachu, S.R., Pergolizzi, J., Taylor, R., Slatkin, N.E., Barrett, A.C., Yu, J., . . . Forbes, W.P. (2015). Efficacy and tolerability of subcutaneous methylnaltrexone in patients with advanced illness and opioid-induced constipation: A responder analysis of 2 randomized, placebo-controlled trials. Pain Practice, 15, 564–571.

DOI Link

Study Purpose

To examine the influence of demographic and baseline characteristics on the efficacy and tolerability of methylnaltrexone (MNTX) in patients with advanced illness and opioid-induced constipation

Intervention Characteristics/Basic Study Process

Data were pooled from two multicenter, randomized, double-blinded, placebo-controlled, phase 3 clinical studies of subcutaneous MNTX (0.15 and 0.03 mg/kg). The primary outcome analyzed was the percentage of patients with rescue medication-free bowel movement (RFBM) within four hours of the first dose.

Sample Characteristics

  • N = 287  
  • AGE = Younger than 65 years (38.2%-49.6%) and 65 years and older (50.4%-61.8%)
  • MALES: 47.3%-56.4%, FEMALES: 43.6%-52.7%
  • KEY DISEASE CHARACTERISTICS: Advanced illness
  • OTHER KEY SAMPLE CHARACTERISTICS: Age, gender, primary diagnosis, baseline constipation-related distress score, baseline oral morphine equivalent dose

Setting

  • SITE: Multi-site

Phase of Care and Clinical Applications

  • PHASE OF CARE: Mutliple phases of care
  • APPLICATIONS: Palliative care

Study Design

  • Randomized and double-blinded study with placebo controlled arm

Measurement Instruments/Methods

  • Chi-squared test to explore the effects of MNTX versus placebo treatment

Results

More than 50% of 165 patients treated with MNTX dose experienced a rescue-free bowel movement (RFBM) within four hours versus 14.6% of the placebo-treated patients. The largest difference was observed in patients taking the MNTX 0.3 mg/kg without cancer versus the placebo group.

Conclusions

Subcutaneous MNTX provides a rapid and robust and consistent RFBM response in patients with advance illness and OIC. MNTX 0.3 mg/kg may have a more favorable response in selected patient populations.

Limitations

  • Baseline sample/group differences of import
  • Unintended interventions or applicable interventions not described that would influence results 

Nursing Implications

MNTX continues to show efficacy for opioid-induced constipation for various types of patients. Additional work is warranted to determine most effective doses.