Gastrointestinal side effects of orlistat may be prevented by concomitant prescription of natural fibers (psyllium mucilloid).

Objectives: This placebo-controlled open study was designed to test the hypothesis that most of the gastrointestinal (GI) side events induced by treatment of obese patients with orlistat (a gastrointestinal lipase inhibitor) could be prevented or ameliorated by concomitant use of natural fibers (psyllium mucilloid).

Design: Two groups of obese women (BMI>27 kg/m(2)) were treated with orlistat 120 mg three times a day. One group (A, n=30) was randomized to receive orlistat and, approximately 6.0 g of orange-flavored psyllium mucilloid dissolved in water and the other group (B, n=30) received orlistat and orange-flavored placebo. At the end of 30 days and 2 weeks of washout, group A switched to placebo and group B received psyllium while continuing orlistat three times a day.

Subjects: Sixty professional women, more than 21-y-old with a body mass index (BMI) between 27.3 and 48.0 kg/m(2), who were not receiving any other medication.

Measurements: Assessments included weekly visits to attending physician, filling a form in which GI events were recorded, monthly measurements of body weight, blood pressure and serum lipids. The frequency and severity of GI events were evaluated by a score system, based on information provided by the patients.

Results: Both groups A and B significantly lost (P<0.01) weight after 60 days of orlistat (A=96.8 to 94.9 kg and B=98.7 to 96.5 kg). Similarly, BMI values declined significantly in both groups. While in the psyllium plus orlistat group (group A) the mean +/-s.e.m. of the scores reflecting GI events was 13.0+/-1.8, the placebo plus orlistat group (B) had a value of 35.9+/-2.7 (P<0.01). When the reverse situation was instituted the placebo and orlistat group presented a mean score of 36.1+/-3.6 and the psyllium plus orlistat a mean score of 8.9+/-1.5 (P<0.01).

Conclusions: Psyllium hydrophilic mucilloid concomitantly prescribed to obese patients receiving 120 mg of orlistat three times a day is an effective and safe adjunct therapy that is helpful in controlling the GI side effects of this pancreatic lipase inhibitor.