Approved by the U.S. FDA in 1999, Xenical^® (orlistat) is a lipase inhibitor for obesity management that acts by inhibiting the absorption of dietary fats.

Xenical prevents enzymes in the gastrointestinal tract from breaking down dietary fats into smaller molecules that can be absorbed by the body. This undigested fat is removed in your bowel movements, and absorption of fat is decreased by about 30 percent.

The recommended dose of Xenical is one capsule with each main meal that includes fat. During treatment, the patient should be on a nutritionally balanced, reduced-calorie diet that contains no more than 30 percent of calories from fat.

Xenical is indicated for obese patients with a body mass index of 30 or more, or for patients with a BMI of 27 or more who also have high blood pressure, high cholesterol, or diabetes.

The most common side effects of Xenical are oily spotting, gas with discharge, fecal urgency, fatty/oily stools and frequent bowel movements.

WARNINGS:

Organic causes of obesity (eg, hypothyroidism) should be excluded before prescribing Xenical.

Preliminary data from a Xenical and cyclosporine drug interaction study indicate a reduction in cyclosporine plasma levels when Xenical was coadministered with cyclosporine. Therefore, Xenical and cyclosporine should not be coadministered. To reduce the chance of a drug-drug interaction, cyclosporine should be taken at least 2 hours before or after Xenical in patients taking both drugs. In addition, in those patients whose cyclosporine levels are being measured, more frequent monitoring should
be considered.

PRECAUTIONS:

Patients should be advised to adhere to dietary guidelines. Gastrointestinal events may increase when Xenical is taken with a diet high in fat (more than 30% of total daily calories from fat). The daily intake of fat should be distributed over three main meals. If Xenical is taken with any one meal very high in fat, the possibility of gastrointestinal effects increases.

Patients should be strongly encouraged to take a multivitamin supplement that contains fat-soluble vitamins to ensure adequate nutrition because Xenical has been shown to reduce the absorption of some fat-soluble vitamins and beta-carotene. In addition, the levels of vitamin D and beta-carotene may
be low in obese patients compared with non-obese subjects. The supplement should be taken once a day at least 2 hours before or after the administration of Xenical, such as at bedtime.

Some patients may develop increased levels of urinary oxalate following treatment with Xenical. Caution should be exercised when prescribing Xenical to patients with a history of hyperoxaluria or calcium oxalate nephrolithiasis.

Weight-loss induction by Xenical may be accompanied by improved metabolic control in diabetics, which might require a reduction in dose of oral hypoglycemic medication (eg, sulfonylureas, metformin) or insulin.