What are the side effects of orlistat?
The most common side effects of orlistat are:
- oily spotting on underwear,
- urgent bowel movements,
- fatty or oily stools,
- increased number of bowel movements,
- abdominal pain or discomfort, and
- inability to control stool (incontinence).
From 1 in 250 and 1 in 70 patients experienced one or more of these symptoms in the first year. Generally, the side effects occurred within three months of starting therapy. In about 50% of patients, the side effects resolved within one to four weeks, but the effects in some patients lasted 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 that causes most of the symptoms. alli causes fewer side effects because it contains half the dose of prescription-strength orlistat. Patients receiving orlistat with a history of oxalate kidney stones may develop increased levels of oxalate in their urine, which may increase the risk of kidney stones.
Liver failure has been reported in patients treated with orlistat. Orlistat should be discontinued if symptoms of liver failure (loss of appetite, anorexia, itching, jaundice, dark urine, light colored stools, or right upper abdominal pain) occur while taking orlistat.
Other serious side effects of orlistat include:
- Serious allergic reactions
- Deficiency in fat-soluble vitamins
What is the dosage for orlistat?
- The recommended prescription dose for Xenical is one capsule (120 mg) three times daily.
- The recommended dose for alli is 60 mg three times daily.
- Orlistat should be taken one hour after or during a meal containing about 15 mg of fat. Meals without fat do not require orlistat.
- No additional benefit has been shown when orlistat was taken in doses greater than 120 mg.
- Patients should eat a nutritionally balanced, reduced calorie diet that contains approximately 30% of calories from fat.
- alli includes an individually tailored online weight loss support program.
Some dietary vitamins bind to fat (vitamins A, D, E and beta- carotene). When orlistat is taken, these vitamins are not absorbed and are eliminated in the stool in increased amounts along with the fat. Therefore, patients taking orlistat should take a multivitamin containing these “fat-soluble” vitamins to ensure that adequate amounts of the vitamins are available for absorption. To ensure that the vitamins in the multivitamins are not bound to fat like the vitamins in the diet, the multivitamin should be taken at least two hours before or several hours after the orlistat.
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Which drugs or supplements interact with orlistat?
- The blood thinning effect of warfarin (Coumadin, Jantoven) depends on the amount of vitamin K in the body, and vitamin K is one of the vitamins that binds to fat. Patients receiving warfarin who begin orlistat should have their blood clotting monitored closely because the orlistat may cause levels of vitamin K to decline. This will increase the effects of warfarin and lead to abnormal bleeding from the warfarin. There is no evidence that a deficiency of vitamin K occurs in patients who are taking orlistat.
- Orlistat may reduce the absorption and blood levels of cyclosporine (Sandimmune) when both drugs are administered together. Therefore, cyclosporine should be administered two hours before or after orlistat, and more frequent monitoring of cyclosporine levels may be needed.
- Hypothyroidism has been reported when orlistat and levothyroxine (Synthroid, Levoxyl, Levothroid, Unithroid) were combined. Patients treated with both orlistat and levothyroxine should be monitored for changes in thyroid function. The orlistat and levothyroxine should be taken at least four hours apart.
Is orlistat safe to take if I’m pregnant or breastfeeding?
What else should I know about orlistat?
What preparations of orlistat are available?
Capsules: 60 mg (alli), 120 mg (Xenical)
How should I keep orlistat stored?
Capsules should be stored at room temperature, 15 C – 30 C (59 F – 86 F)
Medically Reviewed on 3/20/2019
FDA Prescribing Information