Orlistat, a medication prescribed for obesity and sold under the trade name Xenical, now is available in an over-the-counter formulation marketed as Alli (the prescription product will continue to be available at the higher dose). It's recommended for use in adults 18 years of age and older but isn't intended for people who either have difficulty absorbing food or do not need to lose weight. Patients who've undergone organ transplantation shouldn't take it because of a possible interaction with immunosuppressant medication (specifically, cyclosporine). Use of the drug by patients taking anticoagulants or medication to treat diabetes or thyroid disease may not be appropriate, and an NP or a physician should be consulted before a patient starts taking it. Orlistat is dispensed in 60-mg capsules that can be taken as often as three times a day with each meal containing fat. For maximum effect, the drug should be used as part of a regimen that includes a low-calorie, low-fat diet and an exercise program. Because orlistat is a lipase inhibitor that decreases the intestinal absorption of dietary fats, it can have adverse gastrointestinal effects, including diarrhea, flatus with discharge, bowel urgency, oily evacuation, fecal incontinence, and abdominal pain; patients should be made aware of this. Also, because of the possibility that the drug will induce the loss of certain nutrients, patients taking orlistat should be instructed to take a multivitamin at bedtime.