Reviews for Primary Care - Fall 2007 - (Page 24) Chronic Constipation and Functional Bowel Disorders continued usually they are not enough to make an accurate diagnostic distinction between constipation subtypes. Question: What are the most effective ways to manage patients with suspected pelvic floor dyssynergia? Panel: Although various laxatives are utilized for treatment of pelvic floor dyssynergia, their efficacy is limited. The strongest clinical trial evidence for effective treatment of pelvic floor dyssynergia that we currently have is related to biofeedback. Two recently published clinical trials have indicated that biofeedback is more effective at relieving pelvic floor dyssynergia than diazepam, placebo, or PEG 3350.62,63 The most recent study was a randomized, controlled trial by Heymen and colleagues that was designed to determine whether biofeedback was more effective than the muscle relaxant diazepam (5 mg given orally 1 hour before attempted defecation) or placebo in 84 patients with pelvic floor dyssynergia–type constipation.62 Biofeedback was found to be superior to diazepam and placebo in the intention-totreat analysis. Biofeedback patients had significantly more unassisted bowel movements at follow-up compared with placebo (P .005), with a trend favoring biofeedback over diazepam (P .067). Additionally, biofeedback patients reduced pelvic floor electromyography during straining significantly more than diazepam patients (P .001). Another recently published study from Chiarioni and colleagues compared biofeedback to a common laxative, PEG 3350, and education in patients with chronic and severe pelvic floor dyssynergia.63 In this parallel-group, randomized, controlled study, participants initially were treated with fiber 20 g/d plus enemas or suppositories up to twice weekly. Nonresponders were randomized to either 5 weekly biofeedback sessions (n 54) or PEG 3350 (14.629.2 g/d) plus 5 weekly counseling sessions in preventing constipation (n 55). After 2 years of follow-up, the biofeedback arm clearly outperformed the laxative arm despite the ability of researchers to titrate the laxative over time.63 Major improvement was reported by 43 of 54 (80%) biofeedback patients versus 12 of 55 (22%) laxative-treated patients (P .001). The benefits of biofeedback were sustained at 12- and 24-month follow-ups. Biofeedback also produced greater reductions in straining, sensations of incomplete evacuation and anorectal blockage, use of enemas and suppositories, and abdominal pain (all P .01). Stool frequency also increased in both groups. All biofeedbacktreated patients reporting major improvement were able to relax the pelvic floor and defecate a 50-mL balloon at 6 and 12 months. The investigators concluded that 5 biofeedback sessions are more effective than continuous PEG 3350 for treating pelvic floor dyssynergia, and benefits last at least 2 years. These 2 studies suggest that for patients with pelvic floor dyssynergia, biofeedback may very well be the best treatment option that can be offered. The only drawback with biofeedback is its relatively limited availability in the community setting. Question: What about IBS-C? Is there anything new in this arena? Panel: There is an abstract from DDW 2006 by John Johanson and colleagues that looked at approximately 50 patients with IBS-C in a 12-week, double-blind, placebocontrolled trial.64 This was actually a dose-ranging trial of lubiprostone for IBS-C. Subjects recorded weekly data relating to their dosing, abdominal symptoms, bowel movements, and the need for rescue medication. They found significant dose-dependent trends, observed in at least 2 out of the 3 months, with improvements in abdominal discomfort/pain, bloating, spontaneous bowel movement frequency, consistency, straining, and overall constipation severity in the patients taking lubiprostone. The improvements noted in this trial were highest among the patients receiving lubiprostone 24 g twice daily. Panel: Doug Drossman presented some late-breaking data at DDW 2007 about the effect of lubiprostone on patients with IBS-C.61 This is actually a phase III clinical trial of lubiprostone at a lower dose (8 g twice daily) for 12 weeks. It was a multicenter, double-blind, randomized, placebocontrolled trial in 1167 subjects. The primary efficacy variable in this study was very binary. It was determined by asking the patients a simple question: “How would you rate your relief of IBS symptoms over the past week compared to how you felt before you entered the study?” The results showed that patients randomized to lubiprostone felt overall that their IBS-C symptoms had improved more than patients randomized to placebo (17.9% vs 10.1%; P .001). Question: What is the most effective treatment strategy in pregnant patients with chronic constipation or IBS-C? Panel: The pregnancy classes for the osmotic laxatives as well as lubiprostone are as follows: lactulose is class B, PEG 3350 is class C, and lubiprostone is class C.25,65 Neither PEG 3350 nor lubiprostone has been studied in pregnant humans; however, lactulose has been studied. An abstract presented at DDW 2006 looked at lactulose treatment in 63 pregnant Chinese women.66 Study participants had stool forms that were hard and lumpy (Bristol Stool Form Scale types 1, 2, or 3) and consistent with constipation. The investigators found lactulose to be a safe and effective therapy for these patients, and there 24 VOL. 1 NO. 1 2007 REVIEWS FOR PRIMARY CARE
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