How does this medication work? What will it do for me?

Orlistat belongs to a class of medications known as anti-obesity agents, specifically gastrointestinal lipase inhibitors. When combined with a mildly reduced-calorie diet that contains no more than 30% of calories from fat, orlistat is used to help obese people lose weight and maintain weight loss.

Lipase is an enzyme that is needed to breakdown dietary fats into fatty acids, which is the form of fat that gets absorbed. Orlistat blocks the action of lipase and therefore prevents dietary fat from being absorbed. At the recommended dose, orlistat inhibits dietary fat absorption by approximately 30%.

This medication should only be used by people who have a body mass index (BMI) of 30 kg/m² or higher, or by people with a BMI of 27 kg/m² or higher with other health risk factors such as high blood pressure, type 2 diabetes, high cholesterol, or large waist measurement. BMI is not a direct measure of fat and these guidelines do not apply to athletes and pregnant women.

BMI is calculated by dividing your body weight in kilograms by the square of your height in metres. For example, if you weigh 150 lbs (68 kg) and are 5 ft 8 in (1.73 m) tall, divide 68 by (1.73×1.73), or 2.99. The result is a BMI of 22.7 kg/m².

Orlistat can also be used in combination with diabetes medications to improve blood glucose control in overweight or obese people with type 2 diabetes whose blood glucose levels are inadequately controlled with diet, exercise, and diabetes medications (e.g., glyburide, insulin, metformin).

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

Each turquoise capsule, with "Xenical 120" printed in black ink, contains 120 mg of orlistat. Nonmedicinal ingredients: gelatin, indigo carmine, microcrystalline cellulose, povidone K30, sodium lauryl sulfate, sodium starch glycolate, talc, and titanium dioxide.

How should I use this medication?

The recommended adult dose is 120 mg three times daily with each main meal (breakfast, lunch, and dinner) or up to 1 hour after the meal. If you occasionally miss a meal or the meal does not contain fat, do not take the dose of orlistat. Swallow the capsule whole with some water.

Orlistat should be taken with a mildly reduced-calorie diet that contains no more than 30% of calories from fat, as recommended by your doctor, dietitian, or other health care professional.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, it can be taken up to 1 hour after a meal and still be effective. However, if it is greater than an hour when you remember, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature in the original package, protect it from moisture, and keep it away from heat and out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take this medication if you:

  • are allergic to orlistat or any ingredients of the medication
  • have cholestasis (a condition where bile excretion in the liver is stopped)
  • have chronic malabsorption syndrome (a condition where you do not absorb nutrients from food properly)

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • discoloured stools
  • diarrhea
  • gas with discharge
  • inability to control bowel movements
  • increases in bowel movements
  • oily or fatty stools
  • oily spotting of underclothes
  • urgent need to have a bowel movement

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • signs of kidney problems (e.g., increased urination at night, decreased urine production, blood in the urine, swelling of the hands or feet, painful urination)
  • swelling of feet or ankles
  • symptoms of gallstones (such as pain in the upper right part of the abdomen that may be accompanied by nausea and vomiting)
  • symptoms of kidney stones (such as back pain and blood in the urine)
  • symptoms of liver damage (e.g., abdominal pain, clay-coloured stools, dark urine, loss of appetite, yellow skin or eyes)
  • symptoms of low blood sugar (e.g., cold sweat, cool pale skin, headache, fast heartbeat, weakness

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • bleeding from the rectum
  • signs of an allergic reaction (e.g., hives, shortness of breath or difficulty breathing, swelling of the eyes, mouth, lips, or throat)
  • signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Diabetes: If you have type 2 diabetes and are taking orlistat in combination with other diabetes medications, you may be more at risk of experiencing hypoglycemia (low blood sugar). If you experience hypoglycemia symptoms such as sweating, dizziness, shakiness, hunger, or confusion, contact your doctor. Your doctor may need to adjust the dose of your medication(s). You should continue to monitor your blood sugar levels regularly.

Fat intake: It is very important to follow recommended dietary guidelines while taking orlistat. The risk of side effects associated with the stomach (such as gas with discharge or oily spotting of underclothes) increases when orlistat is taken with a high-fat diet. Your daily intake of fat should be distributed over three main meals and should not be more than 30% of the total calories. Discuss with your doctor or dietitian if you have any concerns or questions regarding how to manage your diet.

Gastrointestinal problems: If you have bowel or rectal problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Bleeding from the rectum has been reported with the use of orlistat. If this occurs, contact your doctor as soon as possible.

Kidney stones: If you have a history of kidney stones, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver: There have been rare reports of severe liver injury in people taking orlistat. If you experience any symptoms such as loss of appetite, yellow skin or eyes, abdominal pain, dark urine, light-coloured stools, or pain in the upper right part of the abdomen, contact your doctor immediately.

Seizures: Orlistat may interact with seizure medications by decreasing the amount of seizure medication that your body absorbs. This can result in increased seizures. If you have a history of seizures, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Thyroid: Orlistat may affect how well your thyroid gland works, possibly by reducing the amount of iodine available from your diet for your body to produce thyroid hormone. If you have hypothyroidism (low thyroid hormone levels), your doctor should closely monitor your condition while you are taking orlistat, as it may affect thyroid levels.

Vitamins: Orlistat may reduce the absorption of beta-carotene and fat-soluble vitamins such as vitamin A, vitamin D, vitamin E, and vitamin K. Talk to your doctor or pharmacist about taking a multivitamin supplement. If you are already on a multivitamin, take it at least 2 hours before or after taking orlistat, or take it at bedtime.

Pregnancy: Orlistat has not been adequately studied in pregnant women. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if orlistat passes into breast milk. If you are a breast-feeding mother and taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of orlistat have not been established for use in children less than 12 years of age.

What other drugs could interact with this medication?

There may be an interaction between orlistat and any of the following:

  • acetazolamide
  • adefovir
  • alfacalcidol
  • amiodarone
  • birth control pills
  • calcitriol
  • certain diabetes medications (e.g., glyburide, gliclazide, insulin, metformin)
  • cobicistat
  • cyclosporine
  • fat-soluble vitamin supplements (e.g., vitamin A, vitamin D, vitamin E, and vitamin K)
  • gabapentin
  • HIV integrase strand inhibitors (e.g., bictegravir, dolutegravir, raltegravir)
  • HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., efavirenz, etravirine, nevirapine)
  • HIV nucleoside reverse transcriptase inhibitors (NRTIs; e.g., abacavir, didanosine, lamivudine, tenofovir, zidovudine)
  • HIV protease inhibitors (atazanavir, lopinavir, ritonavir)
  • levothyroxine
  • maraviroc
  • propafenone
  • seizure medications (e.g., carbamazepine, divalproex, lamotrigine, levetiracetam, phenytoin, phenobarbital, topiramate)
  • stiripentol
  • warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription) and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

All material copyright MediResource Inc. 1996 – 2024. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source: