Objective: To examine the tolerability and efficacy of duloxetine in patients with suspected sphincter of Oddi dysfunction (SOD).
Methods: An open-label, single-center, 12-week trial of duloxetine 60 mg once daily was conducted in 20 patients with suspected SOD. All patients were evaluated by expert pancreato-biliary specialists. The primary outcome measure was a Patient Global Impression of Change (PGIC) scale. Secondary measures included the pain burden, assessed by the Recurrent Abdominal Pain Intensity and Disability scale, the Short-Form Health Survey, and the Hospital Anxiety and Depression Scale. A positive clinical response was defined as a PGIC score of much or very much improved at 3 months and was estimated using a two-sided 90 % confidence interval. The primary outcome was analyzed using a one-sample binomial test at a significance level of 0.10.
Results: Of the 20 screened patients, 18 were enrolled; 14 completed at least one post-baseline evaluation; and 10 patients completed the third month endpoint visit. Patients missing the third month visit were considered non-responders for the primary outcome. Response rates were 90 % for study completers (n = 10; 90 % CI 74-100; p = 0.02) and 64 % for patients who completed at least one post-baseline evaluation (n = 14; 90 % CI 43-85; p = 0.42). Seven patients did not complete the study due to adverse events (mostly fatigue and nausea).
Conclusions: Duloxetine showed an indication of efficacy in the treatment of pain in patients with suspected SOD, but adverse events limited its use. These preliminary, open-label results justify definitive placebo-controlled trials.
Keywords: Abdominal pain; Biliary disease; Pharmacotherapy; Sphincter of Oddi dysfunction.