Orlistat - Dosage | Side Effects

This article was medically reviewed by M.Pharm, Marko Tanaskovic on August 12, 2018. To read more about an author, click here.

Orlistat is an inhibitor of pancreatic lipase and prevents the degradation of fats to the fatty acids and glycerol. It is used for treating obesity.

It should be used in combination with hypocaloric diet in order to achieve healthy weight in overweight people. This medicine has been proved effective in placebo-controlled studies. Most of the Orlistat is excreted unchanged in the feces, and only a small fraction is absorbed. Orlistat has an additional direct cholesterol-lowering effect that is independent of weight reduction.

It is used to help people lose weight especially in people with risk factors, such as: high cholesterol, diabetes and high blood pressure.


Orlistat should be avoided in following conditions:

  • If you are allergic to this medicine or any other similar medications.
  • If you suffer from malabsorption syndrome
  • If you have gallbladder problems
  • If you have thyroid disorders
  • If you have diabetes
  • If you have pancreatic disease
  • If you have liver damage

It is recommended to limit fat intake while taking Orlistat.

Side effects

Orlistat may cause following side effects:

  • Fatty stools (oily)
  • Abdominal pain
  • Rectal pain
  • Headaches
  • Anxiety
  • Fatigue

This medicine should be used only in people who have lost 5.5 pounds (2,5 kg) of body weight by eating a healthy diet in previous month. It should be used only in people between the ages of 18 and 75. Treatment can last for 3 or 6 months depending on achieved weight loss. Treatment should not last more than a year.


Usual dose is 120 mg per day. It need to be taken before or during meal.

Brand names: Alli and Xenical.

Information on this website are provided for educational purposes only and are not intended for medical advice, diagnosis or treatment.

If you have any concerns or questions about your health, you should always consult with a physician or other health-care professional.

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