Evaluation of urinary oxalate levels in patients receiving gastrointestinal lipase inhibitor.
OBJECTIVE
The purpose of this study was to examine the possible effects of a gastrointestinal lipase inhibitor "Orlistat (Xenical)" on the intestinal absorption of oxalate and thereby on the urinary levels of oxalate excretion in overweight patients.


METHODS
Long-term follow-up data of 95 cases (57 men, 38 women; M/W=1.5) were documented. Patients were randomly assigned into two groups. While the patients in group I (n=55) were treated with orlistat (Xenical) for 6 months, patients in group II (n=40) received no specific medication. Calcium, oxalate, and citrate levels were determined in a 24-h urine collection from each patient. To evaluate the significance in the groups as well as the differences between the two groups, ANOVA test was performed and the results were given as mean +/- s.d.


RESULTS
Comparative evaluation of urinary oxalate levels during 3-month follow-up clearly showed that urinary oxalate excretion significantly increased in 34/55 patients (61.8%) in the first group (P<0.05). Of these 34 patients, 30 (88.2%) continued to have increased urinary oxalate excretion during 6-month follow-up (P=0.001). However, our data did not show any significant effect of this medication on urinary citrate and calcium levels during 3- and 6-month follow-up evaluation (P=0.05).


CONCLUSIONS
Our results suggest that increased intestinal absorption of dietary oxalate due to this type of medication in obese patients could make a substantial contribution to urinary oxalate excretion and may increase the risk of stone formation.
Sarica
Kemal
K
Department of Urology, Memorial Hospital, Istanbul, Turkey. kemalsarica@superonline.com
Akarsu
Ersin
E
Erturhan
Sakip
S
Yagci
Faruk
F
Aktaran
Sebnem
S
Altay
Bulent
B
D000328:Adult; D019440:Anti-Obesity Agents / Q000009:adverse effects*; D002118:Calcium / Q000652:urine; D019343:Citric Acid / Q000652:urine; D004791:Enzyme Inhibitors / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006959:Hyperoxaluria / Q000139:chemically induced* / Q000378:metabolism; D007408:Intestinal Absorption / Q000187:drug effects; D007422:Intestines / Q000187:drug effects* / Q000201:enzymology; D007783:Lactones / Q000009:adverse effects*; D008049:Lipase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008297:Male; D009765:Obesity / Q000188:drug therapy* / Q000378:metabolism; D000077403:Orlistat; D019815:Oxalic Acid / Q000652:urine*; D018570:Risk Assessment; D016896:Treatment Outcome; D015854:Up-Regulation; D014545:Urinary Calculi / Q000139:chemically induced
D019440:Anti-Obesity Agents; D004791:Enzyme Inhibitors; D007783:Lactones; D019343:Citric Acid; D000077403:Orlistat; D019815:Oxalic Acid; D008049:Lipase; D002118:Calcium