Orlistat Disease Interactions

The use of orlistat is contraindicated in patients with chronic malabsorption syndrome or cholestasis. Orlistat can worsen the malabsorption in these conditions by reversibly inhibiting lipases that are necessary for the hydrolysis of triglycerides into absorbable free fatty acids and monoglycerides. At the recommended therapeutic dosage of 120 mg three times a day, orlistat inhibits dietary fat absorption by approximately 30%.

Obese, type 2 diabetic patients who achieve weight loss may demonstrate improved metabolic control of their disease as a result of their reduced weight. Therefore, patients with type 2 diabetes mellitus should be monitored during weight-reduction therapy (or therapy that may be expected to induce significant weight loss as a secondary effect) for hypoglycemia and reduced need for oral hypoglycemic medication or insulin, and the dosages of these agents adjusted accordingly. Patients should be apprised of the risk of hypoglycemia and be alert to potential signs and symptoms such as headache, dizziness, drowsiness, nervousness, confusion, tremor, hunger, weakness, perspiration, and palpitation.

At the recommended therapeutic dosage of 120 mg three times a day, orlistat inhibits dietary fat absorption by approximately 30% and has been shown to reduce the absorption of some fat-soluble vitamins and beta-carotene. Therapy with orlistat should be administered cautiously in patients with preexisting deficiency of one or more fat-soluble vitamins (A, D, E and K). Ideally, the deficiency should be corrected prior to initiation of therapy. A multivitamin supplement containing fat-soluble vitamins is recommended during therapy, best taken once a day at least 2 hours before or after the administration of orlistat.

Following treatment with orlistat, some patients may develop increased levels of urinary oxalate as a result of fat malabsorption. Therapy with orlistat should be administered cautiously in patients with a history of hyperoxaluria or calcium oxalate nephrolithiasis.