Detailed Drug Information:

DRUG CLASS AND MECHANISM: Orlistat is a drug that promotes loss of weight bypreventing the digestion and absorption of dietary fat. In the intestine, anenzyme called lipase (produced primarily by the pancreas) breaks apart dietaryfat so that the fat can be absorbed into the body. Orlistat blocks the action oflipase and thereby prevents the breakup and absorption of fat. The unabsorbedfat is excreted in the stool. Orlistat was approved by the FDA in 1999.

PREPARATIONS: Capsules:120 mg

STORAGE: Store tablets and capsules at room temperature, 15-30°C (59-86°F)

PRESCRIBED FOR: Orlistat is combined with a reduced-calorie diet to promoteweight loss. Orlistat also may be used to prevent weight gain after weight hasbeen lost. Candidates for treatment with orlistat are patients who are obesewith a body mass index (a measure of obesity) of more than 30 kg/m2. Candidatesalso include patients with a body mass index of between 27 and 30 kg/m2 if otherrisk factors for arteriosclerosis are present such as high blood pressure,diabetes, and elevated blood cholesterol or triglycerides.

Based on several scientific studies, the average weight loss that is achievedwhen orlistat is taken as recommended for 6 months to one year is 12.4 to 13.4pounds.

DOSING: The recommended dose for orlistat is one capsule (120 mg) three timesdaily. Orlistat should be taken one hour after or during a meal containing fat.Meals without fat do not require orlistat. No additional benefit has been shownwhen orlistat was taken in doses greater than 120mg. Patients should eat anutritionally balanced, reduced calorie diet that contains approximately 30% ofcalories from fat.

Some dietary vitamins bind to fat (vitamins A, D, E and beta- carotene). Whenorlistat is taken, these vitamins are not absorbed and are eliminated in thestool in increased amounts along with the fat. Therefore, patients takingorlistat should take a multivitamin containing these "fat-soluble"vitamins to ensure that adequate amounts of the vitamins are available forabsorption. To ensure that the vitamins in the multivitamins are not bound tofat like the vitamins in the diet, the multivitamin should be taken at least twohours before or several hours after the orlistat.

DRUG INTERACTIONS: The blood thinning effect of warfarin (Coumadin) dependson the amount of vitamin K in the body, and vitamin K is one of the vitaminsthat binds to fat. Patients receiving warfarin who begin orlistat should havetheir blood clotting monitored closely because the orlistat may cause levels ofvitamin K to decline. This will increase the effects of warfarin and lead toabnormal bleeding from the warfarin. There is no evidence that a deficiency ofvitamin K occurs in patients who are taking orlistat. Orlistat may reduce theabsorption and blood levels of cyclosporine (Sandimmune) when both drugs areadministered together. Therefore, cyclosporine should be administered two hoursbefore or after orlistat, and more frequent monitoring of cyclosporine levelsmay be needed.

PREGNANCY: Safe use of orlistat during pregnancy has not been established.Therefore, orlistat is not recommended during pregnancy

NURSING MOTHERS: It is not known if orlistat is secreted in breast milk.Therefore, it probably should not be taken by nursing mothers.

SIDE EFFECTS: The most common side effects of orlistat are oily spotting onunderwear, flatulence, urgent bowel movements, fatty or oily stools, increasednumber of bowel movements, abdominal pain or discomfort, and inability to holdback stool (incontinence). Between 1 in 250 and 1 in 70 patients experienced oneor more of these symptoms in the first year. Generally, the side effectsoccurred within three months of starting therapy. In about 50% of patients, theside effects resolved within one to four weeks, but the effects in some patientslasted six months or longer. To reduce the occurrence of these side effects,meals should contain no more than 30% fat because it is the unabsorbed fat thatcauses most of the symptoms.

Patients receiving orlistat with a history of oxalate kidney stones maydevelop increased levels of oxalate in their urine, which may increase the riskof kidney stones.