ABSTRACT
BACKGROUND: Methylnaltrexone, a selective peripheral acting mu-opioid receptor antagonist, alleviates the constipating effects of opioids without affecting centrally mediated analgesia. OBJECTIVES: To assess the effect of subcutaneous (SC) methylnaltrexone injection on patient-reported constipation symptoms and pain scores. METHODS: A total of 469 subjects on opioids for chronic non-malignant pain with opioid-induced constipation were randomized to methylnaltrexone SC with once daily (QD) or every other day (QOD) dosing or placebo for 4 weeks. Constipation symptoms and pain were assessed using the patient assessment of constipation-symptoms (PAC-SYM) questionnaire and a 11-point scale, respectively, at baseline, Day 14 and Day 28. Change from baseline in PAC-SYM and pain scores were compared between methylnaltrexone and placebo arms at Day 28 using analysis of covariance, with treatment group as factor and baseline score as covariate. RESULTS: A majority of patients were women (60%), average age was 49 years old, and back pain (60%) was the primary pain condition. At Day 28, the methylnaltrexone SC QD group showed a significant improvement over placebo for rectal symptoms (-0.56 vs. -0.30; P < 0.05), stool symptoms (-0.76 vs. -0.43; P < 0.001) and global scores (-0.62 vs. -0.37; P < 0.001). Improvement in stool symptoms (-0.69 vs.-0.43; P < 0.05) and the global scores (-0.52 vs. -0.37; P < 0.05) were significantly greater than placebo in the methylnaltrexone QOD group. Differences in change from baseline in abdominal symptoms and pain scores between the methylnaltrexone SC QD or QOD dosing arms and placebo were not significant. CONCLUSION: The results of our study indicate significant improvement in constipation symptoms with methylnaltrexone QD or QOD dosing compared to placebo without a significant effect on pain scores.
Subject(s)
Analgesics, Opioid/adverse effects , Constipation/drug therapy , Naltrexone/analogs & derivatives , Narcotic Antagonists/therapeutic use , Back Pain/drug therapy , Chronic Disease , Constipation/chemically induced , Double-Blind Method , Female , Humans , Injections, Subcutaneous , Male , Middle Aged , Naltrexone/administration & dosage , Naltrexone/adverse effects , Naltrexone/therapeutic use , Narcotic Antagonists/administration & dosage , Narcotic Antagonists/adverse effects , Quaternary Ammonium Compounds/administration & dosage , Quaternary Ammonium Compounds/adverse effects , Quaternary Ammonium Compounds/therapeutic useABSTRACT
OBJECTIVE: The objective of this study was to determine the relationship between drug-related problems (DRPs) and health-related quality-of-life (HRQoL) in ambulatory, community-dwelling patients with musculoskeletal disorders. METHODS: A 12-month, prospective, observational study was conducted in 12 independent community pharmacies in eastern Iowa. Ambulatory patients with self-reported diagnoses of osteoarthritis, rheumatoid arthritis, or low back pain were invited to participate. During quarterly visits to the pharmacy, patients used touch-screen computers to fill out the Short Form-36 (SF-36) general health survey. Using the results of these point-of-service health status assessments, community pharmacists interviewed patients to assess for DRPs. To examine the influences of different DRP characteristics on HRQoL and controlling for potential confounders, both univariate and multivariate analyses were performed using the change in physical component summary (PCS) score and mental component summary (MCS) score of the SF-36 from baseline to 12 months as the dependent variables. In each regression, the independent variables were those significant variables from the univariate analyses, as well as the types of DRPs and their outcomes. RESULTS: A total of 461 patients were enrolled in the study. Through 12 months, 926 cumulative DRPs were identified. Overall regression models were significant for the PCS and MCS scores, respectively. Two types of DRPs showed significant negative associations with change in PCS: wrong drug and needs additional drug therapy. One type of DRP showed significant negative association with change in MCS: needs additional drug therapy. Resolution or improvement in DRPs showed a significant positive correlation with change in MCS but not PCS. CONCLUSIONS: Two DRPs, needs additional drug therapy and wrong drug, are associated with reduced self-reported physical health in arthritis and low back pain, while the DRP needs additional drug therapy is also associated with reduced self-reported mental health. Resolution of DRPs is associated with improvement in mental health in this cohort.
