Class Name(s):

• 56:92 GI Drugs, Miscellaneous

Pronunciation:

• (or' li stat)

Brand Name(s):

• Alli^®
• Xenical^®

WHY is this medicine prescribed?

Orlistat (prescription and nonprescription) is used to help people lose and maintain weight. Orlistat is in a class of medications called lipase inhibitors. It works by preventing some of the fat in foods eaten from being absorbed in the intestines. This unabsorbed fat is then removed from the body in the stool.

HOW should this medicine be used?

Orlistat comes as a capsule to take by mouth. Take orlistat three times a day with each main meal that contains fat. Take orlistat during a meal or up to 1 hour after a meal. If a meal is missed or does not have fat, you may skip your dose.

Take orlistat exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor or stated on the package.

Are there OTHER USES for this medication?

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What SPECIAL PRECAUTIONS should I follow?

Before taking orlistat,

• tell your doctor or pharmacist if you are allergic to this medication, any part of this medication, or any other medications, foods or substances. Tell your doctor or pharmacist about the allergy and what symptoms you had.
• you should know that some medications should not be taken with orlistat. Other medications may cause dosing changes or extra monitoring when taken with orlistat. Make sure you have discussed any medications you are currently taking or plan to take before starting orlistat with your doctor and pharmacist. Before starting, stopping, or changing any medications while taking orlistat, please get the advice of your doctor or pharmacist.
• you should know that the following nonprescription products may interact with orlistat: vitamin E acetate; beta-carotene. Be sure to let your doctor and pharmacist know that you are taking these medications before you start taking orlistat. Do not start any of these medications while taking orlistat without discussing with your healthcare provider.
• you should know that if you are taking levothyroxine, it should be taken at least 4 hours before or after orlistat.
• you should know that if you are taking cyclosporine, it should be taken at least 3 hours after you have taken orlistat.
• tell your doctor if you have or have ever had cholestasis (condition in which the flow of bile from the liver is blocked), or malabsorption syndrome (problems absorbing food). Your doctor will probably tell you not to take orlistat.
• tell your doctor if you have or have ever had an eating disorder such as anorexia nervosa or bulimia, diabetes, seizure disorder, abnormal heart rhythm, human immunodeficiency virus (HIV), pancreatitis (inflammation or swelling of the pancreas), gallbladder, thyroid, liver, or kidney stones or other kidney problems.
• tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while you are taking orlistat. If you become pregnant while taking orlistat, call your doctor immediately. Orlistat may harm the fetus.

What SPECIAL DIETARY instructions should I follow?

Follow the diet program your doctor has given you. You should evenly divide the amount of daily fat, carbohydrates, and protein you eat over three main meals. If you take orlistat with a diet high in fat (a diet with more than 30% of the total daily calories from fat), or with one meal very high in fat, you are more likely to experience side effects from the medication.

Orlistat blocks your body's absorption of some fat-soluble vitamins and beta carotene. Therefore, when you use orlistat you should take a daily multivitamin that contains vitamins A, D, E, K, and beta-carotene. Read the label to find a multivitamin product that contains these vitamins. Take the multivitamin once a day, 2 hours before or 2 hours after taking orlistat, or take the multivitamin at bedtime. Ask your doctor or pharmacist any questions you might have about taking a multivitamin while you are taking orlistat.

What should I do IF I FORGET to take a dose?

Take the missed dose as soon as you remember it unless it is more than 1 hour since you ate a main meal. If it is longer than 1 hour since you ate a main meal, skip the missed dose and continue on your regular dosing schedule. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

Orlistat may cause side effects. The most common side effect of orlistat is changes in bowel movement (BM) habits. This generally occurs during the first weeks of treatment; however, it may continue throughout your use of orlistat. Tell your doctor if any of these symptoms are severe or do not go away:

• oily spotting on underwear or on clothing, gas with oily spotting
• urgent need to have a bowel movement, loose stools, oily or fatty stools, increased number of bowel movements or difficulty controlling bowel movements
• pain or discomfort in the rectum (bottom), stomach pain
• irregular menstrual periods
• headache
• anxiety

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• hives rash itching difficulty breathing or swallowing
• severe or continuous stomach pain
• excessive tiredness or weakness
• nausea vomiting, loss of appetite pain in the upper right part of the stomach yellowing of the skin or eyes dark-colored urine light-colored stools
• swelling in the legs and feet, decreased urination, frequent or painful urination, blood in the urine, severe pain in the back, belly, or groin area.

Orlistat may cause other side effects. Call your doctor if you have any unusual problems during your treatment with orlistat.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at http://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat, moisture (not in the bathroom), and light.

Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Use a medicine take-back program. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website http://goo.gl/c4Rm4p for more information.

Keep all medication out of sight and reach of children as many containers are not child-resistant. Always lock safety caps. Place the medication in a safe location - one that is up and away and out of their sight and reach. http://www.upandaway.org

What OTHER INFORMATION should I know?

Keep all appointments with your doctor.

You should also follow a program of regular physical activity or exercise while you are taking orlistat. However, before you start any new activity or exercise program, talk with your doctor or health care professional.

Do not let anyone else take your prescription medication. Ask your pharmacist any questions you have about refilling your prescription.

Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™ Copyright, 2026. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: October 15, 2026.