Peripherally restricted μ-opioid receptor antagonists: a review

A phase III randomized controlled study on the efficacy and improved bowel function of prolonged-release (PR) oxycodone-naloxone (up to 160/80 mg daily) vs oxycodone PR

BACKGROUND

Oxycodone/naloxone (OXN PR) is a prolonged-release formulation containing oxycodone and naloxone in a 2:1 ratio. This study aimed to evaluate the tolerability and efficacy of doses up to OXN160/80 mg PR compared with oxycodone prolonged-release formulation (OxyPR) in a randomised controlled trial.

METHODS

Two hundred and forty-three patients were randomised to treatment with OXN PR (n = 123) or OxyPR (n = 120) during the 5-week double-blind study. Measured were: opioid-induced constipation [bowel function index score (BFI)]; analgesic efficacy (NRS 0-10); daily laxative rescue medication use; rescue medication use, and the number of complete spontaneous bowel movements (CSBMs) per week. A subanalysis was conducted in cancer patients.

RESULTS

Greater reductions in mean BFI scores were reported for the OXN PR group compared with OxyPR from Week 1 onwards; at Week 5 the mean change from baseline was -32.5 versus -14.2. Average 24-h pain scores were low and remained stable in the range 3-4 in both treatment groups. Analgesic rescue medication use was similar between the groups. Patients receiving OXN PR used significantly lower mean daily doses of laxative rescue medication than those receiving OxyPR (P = 0.006). The number of CSBM in the OXN PR group approximately doubled compared with a 25% decrease in the OxyPR group. Comparable results to the total study population were reported in the cancer patient subgroup.

CONCLUSIONS

OXN PR in daily doses of up to 160/80 mg significantly improves bowel function compared with equivalent doses of OxyPR while still providing comparable analgesic efficacy.

SIGNIFICANCE

Effective analgesia can be achieved using oxycodone/naloxone PR up to 160/80 mg daily without compromising bowel function. A similar outcome was reported in cancer and non-cancer patients.

A review of laxative therapies for treatment of chronic constipation in older adults

BACKGROUND

Multiple studies have addressed the treatment of chronic constipation in adults in general; however, less guidance is available for treating this condition in older patients.

OBJECTIVE

The aim of this paper was to review the effectiveness of laxatives for chronic constipation in the elderly.

METHODS

Medline, Web of Science, international Pharmaceutical Abstracts, and the Cochrane database of Systematic Reviews were searched for english-language articles evaluating the treatment of chronic constipation in older individuals from the inception of the databases until October 2010. Search terms included constipation, treatment, laxative, elderly, and geriatric. Articles were excluded if the mean age was <65 years.

RESULTS

Thirty-one trials were identified. These studies varied widely in terms of methodology, quality, sample size, efficacy end points, and duration. Mean stool frequency was 9.08 bowel movements per week with psyllium and 8.29 per week with calcium polycarbophil (P = 0.04). docusate sodium daily, docusate sodium q12h, and docusate calcium daily for 3 weeks produced a mean stool frequency of 1.95 bowel movements per week versus 1.50 for placebo (P = NS), 2.29 versus 1.76 (P = NS), and 2.83 versus 1.75 (P<0.02), respectively. Mean stool frequency with lactulose versus placebo was 0.7 and 0.5 bowel movements per day (P<0.02). in patients receiving polyethylene glycol or lactulose, mean stool frequency was 1.3 and 0.9 bowel movements per day (P = 0.005). in a study comparing senna plus a bulking agent with lactulose, mean stool frequency was 4.5 per week for the combination product versus 2.2 per week for lactulose (P<0.001). A study comparing sodium picosulfate with senna reported a mean stool frequency of 0.71 and 0.63 per day (P value not reported). Lubiprostone was associated with 5.69 spontaneous bowel movements per week versus 3.46 per week for placebo (P = 0.001).

CONCLUSIONS

Higher-quality trials evaluating the treatment of constipation in older patients are needed to create a basis for more definitive recommendations in this population. The approach to older adults with constipation should be individualized.