Background:Rifaximin plus mesalazine has been showed to be more effective than rifaximin alone in the treatment of recurrent and complicated diverticulitis of the colon. We investigated the effectiveness of the combination rifaximin/mesalazine followed by mesalazine alone to evaluate tolerability and effectiveness in symptomatic remission in uncomplicated diverticular disease.Material/Methods: We studied 90 consecutive patients (39 M, 51 F, mean age 67.2 yrs, range 32–91 yrs) with symptomatic uncomplicated diverticular disease. We assessed the following symptoms, scoring them on a quantitative scale: 1) constipation, 2) diarrhea, 3) abdominal pain, 4) rectal bleeding, and 5) mucus with stools. All were treated with 800 mg/day rifaximin plus 2.4 gr/day mesalazine for 10 days, followed by 1.6 gr/day mesalazine for 8 weeks. They were re-evaluated at the end of mesalazine-alone treatment.Results: Eighty-six patients completed the study (95.56%): the total score decreased from 1439 to 44 (p<0.001). 70 patients (per-protocol: 81.40% (C.I.: 67–94%); on intention-to-treat: 77.78% (C.I.: 60-85%)) were completely asymptomatic after the 8th week of treatment with mesalazine alone (total symptomatic score: 0), while 16 (per-protocol: 18.60%; on intention-to-treat: 17.77%) showed only slight symptoms (total score: 44). Two (2.22%) showed recurrence of diverticulitis after 4 and 6 weeks of treatment with mesalazine alone. Two patients (2.22%) were withdrawn from the study for diarrhea after starting mesalazine. Two others (2.22%) showed transitory pruritus (one) and epigastric pain (one).
Conclusions: The results show that rifaximin/mesalazine followed by mesalazine alone is extremely effective in resolving symptoms in patients with symptomatic uncomplicated diverticular disease.

Keywords: Aged, 80 and over, Anti-Inflammatory Agents, Non-Steroidal - administration & dosage, Diverticulitis - drug therapy, Drug Therapy, Combination, Gastrointestinal Agents - administration & dosage, Mesalamine - administration & dosage, Prospective Studies, Remission Induction, Rifamycins - administration & dosage, Time Factors, Aged, 80 and over, Anti-Inflammatory Agents, Non-Steroidal - administration & dosage, Diverticulitis - drug therapy, Drug Therapy, Combination, Gastrointestinal Agents - administration & dosage, Mesalamine - administration & dosage, Prospective Studies, Remission Induction, Rifamycins - administration & dosage, Time Factors