Skip to main content

Orlistat

Generic name: orlistat [ OR-li-stat ]
Brand names: Alli, Xenical
Drug class: Peripherally acting antiobesity agents

Medically reviewed by Kaci Durbin, MD. Last updated on Feb 26, 2024.

What is orlistat?

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

Orlistat is used to aid in weight loss, or to help reduce the risk of regaining weight already lost. This medicine must be used together with a reduced-calorie diet and increased physical activity. Orlistat is for use only in adults that are overweight or obese.

Xenical is the prescription-strength form of orlistat. The Alli brand is available without a prescription.

Warnings

Do not take orlistat if you are pregnant.

You should not use this medicine if you have a digestive disorder (problems absorbing food). You should not use Xenical if you have gallbladder problems, or if you are pregnant. Do not use Alli if you have had an organ transplant, if you use cyclosporine, or if you are not overweight.

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.

Before taking this medicine

You should not use orlistat if you are allergic to it, if you have malabsorption syndrome (an inability to absorb food and nutrients properly), or if you are pregnant.

You also should not use Xenical if you have:

Do not use Alli if:

To make sure orlistat is safe for you, tell your doctor if you have ever had:

Do not use orlistat if you are pregnant. Weight loss is not recommended during pregnancy, even if you are overweight. Stop taking this medicine and tell your doctor right away if you become pregnant.

Taking orlistat can make it harder for your body to absorb certain vitamins. These vitamins are important if you are nursing a baby. Do not use this medicine without a doctor's advice if you are breast-feeding a baby.

Xenical is not approved for use by anyone younger than 12 years old. Do not give Alli to anyone under 18 years old.

How should I take orlistat?

Use orlistat exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Never share orlistat with another person, especially someone with a history of eating disorders.

Read all patient information, medication guides, and instruction sheets provided to you. Ask your doctor or pharmacist if you have any questions.

Orlistat is usually taken 3 times per day with each main meal that contains some fat (no more than 30% of the calories for that meal). You may take the medicine either with your meal or up to 1 hour after eating.

If you skip a meal or you eat a meal that does not contain any fat, skip your dose for that meal.

The fat content of your daily diet should not be greater than 30% of your total daily caloric intake. For example, if you eat 1200 calories per day, no more than 360 of those calories should be in the form of fat.

Read the label of all food items you consume, paying special attention to the number of servings per container. Your doctor, nutrition counselor, or dietitian can help you develop a healthy eating plan.

Orlistat is only part of a complete program of treatment that also includes diet and exercise. 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.

Orlistat can make it harder for your body to absorb certain vitamins, and you may need to take a vitamin and mineral supplement while you are taking this medicine. Follow your doctor's instructions about the type of supplement to use. Take the supplement at bedtime, or at least 2 hours before or after you take orlistat.

Store at room temperature away from moisture, heat, and light. Keep the bottle tightly closed. Throw away any unused orlistat after the expiration date on the medicine label has passed.

What happens if I miss a dose?

Take the missed dose as soon as you remember, but no more than 1 hour after eating a meal. If it has been more than an hour since your last meal, skip the missed dose and take the medicine at your next regularly scheduled time. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What to avoid

Avoid eating high-fat meals or you could have unpleasant side effects on your stomach or intestines.

If you also take cyclosporine, do not take it within 3 hours before or 3 hours after you take orlistat.

If you also take levothyroxine (such as Synthroid), do not take it within 4 hours before or 4 hours after you take orlistat.

Orlistat side effects

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

Stop using orlistat and call your doctor at once if you have:

Common orlistat side effects are caused by its fat-blocking action. These are signs that the medicine is working properly. These side effects are usually temporary and may lessen as you continue using this medicine:

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.

Dosing information

Usual Adult Dose for Obesity:

120 mg orally three times a day with each main meal containing fat. The dose may be taken during the meal or within 1 hour of completing the meal.

Usual Pediatric Dose for Obesity:

12 years or older:
120 mg orally three times a day with each main meal containing fat. The dose may be taken during the meal or within 1 hour of completing the meal.

What other drugs will affect orlistat?

Ask a doctor or pharmacist if it is safe for you to use orlistat if you are also using any of the following drugs:

This list is not complete. Other drugs may interact with orlistat, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use orlistat only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.