A team of Canadian researchers, led by Dr.
Matthew Weir of the University of Western Ontario, noticed an increase in kidney damage among people
consuming the weight loss drug Orlistat, sold as "Xenical".
Using Ontario health data, they found that the
incidence of kidney damage needing
hospitalisation was only 0.5% prior to starting the drug Orlistat. However once
the drug was started for weight reduction, they found that the incidence
of hospitalisation. These findings were
recently published in Archives of Internal Medicine.
Between January 2002 and March
2008, among 953 new orlistat subjects, five patients experienced a kidney
injury event in the year prior to starting on the diet pill. Wherein, 18
patients experienced an event within 12 months after filling their prescription
(p=0.01). Dr. Weir, as a "test of specificity," also tracked upper GI
bleeding in the same fashion and found hardly any differences in rates of upper
gastrointestinal bleeds before and after orlistat consumption.
Dr. Weir, who authored the study,
said "A few case reports found kidney
problems in people on Xenical, which were not originally listed as the drug's
. He was quick to add further that, "I would like to make it clear that this study should be
interpreted cautiously. It is observational and cannot prove causality".
Drug-safety watchdog "Public
Citizen" sent a letter to FDA demanding that the company should remove both
prescription and OTC Orlistat from the market, citing new data obtained from
FDA adverse-reaction files. This data
included 73 cases of kidney stones and 47 cases of acute pancreatitis.
Previously, U.S. health officials also warned against rare cases of liver damage in patients on Roche's Xenical and
The active ingredient of both drugs (orlistat)
inhibits the absorption of fat in the gut.
Dr. Donald E. Greydanus, a
Pediatrician at Michigan State University, who was not a part of the study
warned, "This is an important outcome
and it illustrates that anyone taking "so-called-weight loss"
be under the strict scanner of a trusted physician."
Dr. Weir concluded by saying, "The take-home message is that
patients on orlistat should have their kidney function carefully monitored on a