Orlistat (By mouth)

Orlistat (OR-li-stat)

Helps you reach and maintain a healthy weight.

Brand Name(s):

Alli, Xenical

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. Do not use it if you had an allergic reaction to orlistat, or if you are pregnant.

How to Use This Medicine:


  • Follow the instructions on the medicine label if you are using this medicine without a prescription.
  • Take this medicine during each main meal or up to 1 hour after a meal.
  • This medicine works by keeping your body from absorbing some of the fat in your meal. If you skip a meal or eat a meal that does not contain any fat, do not take the medicine. It will not do anything.
  • Eat a well-balanced, reduced-calorie meal plan. Divide the amount of protein, fats, and carbohydrates evenly among your 3 daily meals.
  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
  • Missed dose: You may take this medicine up to 1 hour after the meal. If more than 1 hour has passed, skip your dose and just take your next dose with your next meal. Do not use extra medicine to make up for a missed dose.
  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Some foods and medicines can affect how orlistat works. Tell your doctor if you use any of the following:
    • Amiodarone
    • Blood thinner (including warfarin)
    • Medicine to treat diabetes (including insulin)
    • Medicine to treat HIV/AIDS (including atazanavir, emtricitabine, emtricitabine/efavirenz/tenofovir disoproxil fumarate, lopinavir/ritonavir, ritonavir, tenofovir disoproxil fumarate)
    • Medicine to treat seizures
  • Cyclosporine: Take at least 3 hours after you take orlistat.
  • Levothyroxine: Take at least 4 hours before or after you take orlistat.
  • Multivitamin supplement: Take at least 2 hours before or after you take orlistat, such as at bedtime.

Warnings While Using This Medicine:

  • It is not safe to take this medicine during pregnancy. It could harm an unborn baby. Tell your doctor right away if you become pregnant.
  • Tell your doctor if you are breastfeeding, or if you have kidney disease, liver disease, digestion problems, diabetes, gallbladder problems, heart rhythm problems, seizures, thyroid problems, or an eating disorder (such as anorexia or bulimia).
  • This medicine may cause the following problems:
    • Liver damage
    • Higher risk of kidney stones
    • Gallbladder or bile flow problems, gallstones
  • Bowel side effects can be worse if you eat a meal that is more than 30% fat. The undigested fat comes out in your bowel movements. To reduce side effects, divide your daily intake of fat evenly over your 3 main meals each day.
  • Take a multivitamin supplement that contains vitamins A, D, E, and K with beta carotene. Orlistat keeps your body from absorbing some of the vitamins from food.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes
  • Decrease in how much or how often you urinate, sharp back pain just below the ribs, or painful urination
  • Severe diarrhea
  • Severe stomach pain with nausea and vomiting

If you notice these less serious side effects, talk with your doctor:

  • Increases in bowel movements, loss of bowel control, or the need to have a bowel movement right away
  • Passing gas with oily discharge
  • Passing oil or fat with your bowel movements or between bowel movements

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 11/6/2020

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