Brand Names: alli, Xenical

Generic Name: orlistat (Pronunciation: OR li stat)

• What is orlistat (Alli)?
• What are the possible side effects of orlistat (Alli)?
• What is the most important information I should know about orlistat (Alli)?
• What should I discuss with my healthcare provider before taking orlistat (Alli)?
• How should I take orlistat (Alli)?
• What happens if I miss a dose (Alli)?
• What happens if I overdose (Alli)?
• What should I avoid while taking orlistat (Alli)?
• What other drugs will affect orlistat (Alli)?
• Where can I get more information?

What is orlistat (Alli)?

Orlistat blocks some of the fat that you eat, keeping it from being absorbed by your body.

Orlistat is used together with a reduced-calorie diet and weight maintenance to treat obesity in people with certain risk factors (such as diabetes, high blood pressure, and high cholesterol or triglycerides).

Orlistat may also be used for other purposes not listed in this medication guide.

It is dangerous to purchase orlistat on the Internet or from vendors outside of the United States. Medications distributed from Internet sales may contain dangerous ingredients, or may not be distributed by a licensed pharmacy. Samples of "Alli" purchased on the Internet have been found to contain sibutramine (Meridia), a prescription weight loss medication that can have dangerous side effects in certain people. For more information, contact the U.S. Food and Drug Administration (FDA) or visit www.fda.gov/buyonlineguide.

What are the possible side effects of orlistat (Alli)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop taking orlistat and call your doctor at once if you have severe pain in your upper stomach spreading to your back, nausea and vomiting, and a fast heart rate. These could be signs of pancreatitis.

The following side effects occur commonly with the use of orlistat. They are the natural effects of orlistat's fat-blocking action and are actually signs that the medication is working properly. These side effects are usually temporary and may lessen as you continue treatment with orlistat:

• oily spotting in your undergarments;
• oily or fatty stools;
• orange or brown colored oil in your stool;
• gas with discharge, an oily discharge;
• loose stools, or an urgent need to go to the bathroom, inability to control bowel movements;
• an increased number of bowel movements;
• stomach pain, nausea, vomiting, diarrhea, rectal pain; or
• weakness, dark urine, clay-colored stools, itching, loss of appetite, or jaundice (yellowing of the skin or eyes).

Other side effects that may occur while taking orlistat include:

• problems with your teeth or gums;
• cold symptoms such as stuffy nose, sneezing, cough;
• fever, chills, sore throat, flu symptoms;
• headache, back pain; or
• mild skin rash.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the Alli (orlistat 60 mg) Side Effects Center for a complete guide to possible side effects »

What is the most important information I should know about orlistat (Alli)?

Do not take this medication if you are allergic to orlistat, or if you have gallbladder problems, or chronic malabsorption syndrome (an inability to absorb food and nutrients properly).

Before taking orlistat, tell your doctor if you have an underactive thyroid, a history of gallstones or pancreatitis, type 1 or type 2 diabetes, an eating disorder, liver disease, or if you take other weight-loss medications (prescription or over-the-counter).

Do not give over-the-counter orlistat (Alli) to a child younger than 18 years old. Prescription orlistat (Xenical) should not be used by anyone age 12 to 18 without the advice of a doctor.

Orlistat should be used only by the person it was prescribed or recommended for. Never share orlistat with another person, especially someone who has a history of eating disorder. Keep the medication in a place where others cannot get to it.

Orlistat is only part of a complete program of treatment that also includes diet, exercise, and weight control. Your daily intake of fat, protein, and carbohydrates should be evenly divided over all of your daily meals. Follow your diet, medication, and exercise routines very closely.

Avoid a diet that is high in fat. High-fat meals taken in combination with orlistat can increase your risk of unpleasant side effects on your stomach or intestines.