1 What is Alli?

Brand: Alli, Xenical

Generic: Orlistat

Alli is used with a reduced-calorie diet to assist in losing weight and to keep weight from returning. It is also used in overweight people who may have diabetes, hypertension (high blood pressure), high cholesterol or heart disease.

Orlistat works by keeping your intestines from absorbing some of the fats from the food that you eat. The undigested fat is removed through bowel movements.

This medication is available both over the counter and by prescription.

This product is available in the following forms:

  • Capsule

2 What to Know Before Using

As with all medicines, the risks of using Alli must be compared to how much this medication will help you. This is a decision that you and your doctor will make together.

For this medication, there are many things that need to be considered:

  • AllergiesInform your doctor if you have ever had an allergic reaction to Doxorubicin or to any other medications. It is also important to inform your doctor of any non-medicine allergies such as foods, dyes, preservatives or animals. 
  • Pediatric: Up-to-date pediatric appropriate studies have not indicated any problems that would limit the use of this medication. Safety and efficacy have not been established in children younger than 12 years of age.
  • Geriatric: Up-to-date studies have not shown any problems specific to the elderly that would limit the use of this medication in the elderly population.
  • Pregnancy: This medication is listed as Pregnancy Category X. This means that studies in animals or pregnant women have demonstrated positive evidence of fetal abnormalities. This drug should not be used in women who are or may become pregnant, as the risk obviously outweighs any benefits.
  • Breastfeeding: There are no up-to-date studies in women for determining infant risk when using this medication while breastfeeding. Weigh the potential risks with the benefits before taking this medication while breastfeeding.
  • Drug Interactions: Certain medications should not be used together. However, in certain cases, two medications may be used together, even if an interaction might occur. In these cases,your doctor may want to change your dose or take other precautions.When taking this medication, it is important that you inform your doctor if you are taking any of the medications listed below. The following interactions were selected on the basis of potential significance and are not all-inclusive.Using this medication with any of the following medication is not recommended, but may be unavoidable in some cases. Your doctor may make the decision not to treat you with this medication or change some of the other medications you take:
    • Carbamazepine
    • Clobazam
    • Clonazepam
    • Clorazepate
    • Cyclosporine
    • Diazepam
    • Eslicarbazepine Acetate
    • Ethosuximide
    • Ethotoin
    • Ezogabine
    • Felbamate
    • Fosphenytoin
    • Gabapentin
    • Gabapentin Enacarbil
    • Lacosamide
    • Lamotrigine
    • Levetiracetam
    • Lorazepam
    • Methsuximide
    • Midazolam
    • Oxcarbazepine
    • Perampanel
    • Phenobarbital
    • Phenytoin
    • Piracetam
    • Pregabalin
    • Primidone
    • Rufinamide
    • Stiripentol
    • Tiagabine
    • Topiramate
    • Valproic Acid
    • Vigabatrin
    • ZonisamideUsing this medication with any of the following medications may increase your risk of side effects. However, using both medications may be the best treatment for you.If both medications are prescribed together, your doctor may change the dose or how often you take one or both medications:
    • Linoleic Acid
    • Warfarin
  • Other Interactions: Certain medications should not be used while eating, or while eating certain foods  in case of negative interactions. Using alcohol or tobacco with certain medications may also cause negative interactions. Talk with your doctor about the use of your medication with food, alcohol or tobacco.
  • Other Medical Problems: Pre-existing medical problems may affect the use of this medication.
    Be sure to tell your doctor if you have any other medical problems, especially: 
    • Diabetes 
    • Underactive thyroid - Use with caution. May increase risk for more serious side effects.
    • Eating disorders (i.e. anorexia nervosa or bulimia) 
    • Hyperoxaluria (high oxalic acid in the urine)
    • Kidney failure 
    • Kidney stones 
    • Liver disease - Use with caution. May make these conditions worse.
    • Gallbladder problems 
    • Malabsorption syndrome (problems with absorbing or digesting food) - Should not be used in patients with these conditions.

3 Proper Usage

Only take Alli as directed by your doctor. Do not take more, less or for a longer or shorter period of time than your doctor tells you.

This medication comes with a patient information brochure. It is very important that you read this information. Ask your doctor if you have any questions.

This medication prevents the absorption of fats in foods you consume. You should take it with liquids during the meal or up to 1 hour after eating. 

If you occasionally miss a meal or eat a meal that contains no fat, you should skip the dose of this medication.

Because this medication may decrease some of the vitamins that your body absorbs from food, you will need to take a multivitamin supplement once a day. Take the supplement at least 2 hours before or after taking this medication or at bed-time.

When using this medication, your diet should contain no more than 30% of fat calories. More fat in your diet will increase the side effects of this medication. 

Your diet should be nutritionally balanced and your daily intake of fat, carbohydrates and protein should be distributed over three main meals.

Be sure to follow your doctor’s instructions for a reduced calorie diet plan and regular exercise. Ask your doctor before starting any exercise program.

If you are using Cyclosporine and Levothyroxine, do not take them at the same time as you take this medication. It is best to take Cyclosporine at least 3 hours before or after taking Orlistat. Levothyroxine must be used at least 4 hours before or after taking Orlistat.


Different patients will be given a different dose of this medication based on the strength of the medication. The number of doses you take each day, the time between doses and the length of time you take this medication depends on the reason you are taking this medication.

The following information only includes the average dose of this  medication. If your dose is different, do not change it without first speaking to your doctor.

  • Adults and teenagers - 120mg 3 times a day with meals containing fat.
  • Children younger than 12 years of age - Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of this medication, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and resume your normal dosing schedule. Do not double dose.


Store this medication in a closed container at room temperature. Keep it away from heat, moisture and direct light. Do not freeze.

Keep out of the reach of children. Do not keep expired medication or medication you no longer need. Ask your doctor how to dispose of any medication you do not use.

4 Precautions to Take

It is very important that your doctor checks in with you often while you are receiving Alli to make sure that it is working  properly.

Using this medication while pregnant can harm your unborn child. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant, inform your doctor immediately.

This medication may cause a serious type of allergic reaction called anaphylaxis, which is life-threatening and requires immediate emergency medical help.

Inform your doctor immediately if you have a rash, itching, hoarseness, difficulty breathing, difficulty swallowing or swelling in the hands, face or mouth while using this medication.

For patients with diabetes: weight loss may result in an improvement of your condition and your doctor may need to change your dose of oral diabetes medication or insulin.

Stop using this medication immediately and inform your doctor if you have pain or tenderness in the upper stomach, pale stool, dark urine, loss of appetite, nausea, unusual itching, unusual fatigue or weakness or yellow eyes or skin (jaundice). These may be signs of a serious liver problem.

This medication may increase your risk of kidney stones. Inform your doctor immediately if you have blood in the urine, nausea and vomiting, pain in the groin or genitals or sharp back pain below the ribs.

Weight loss with this medication may increase your risk of gallstones. Inform your doctor immediately if you have severe stomach pain with nausea and vomiting.

Don’t take other prescription or over the counter medications or supplements unless you have discussed them with your doctor.

5 Potential Side Effects

Alli may produce unwanted affects along with the intended effects. Although not all of these side-effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if you experience any of the following side-effects:

More Common

Less Common

  • Tightness in the chest
  • Tooth or gum problems
  • Wheezing


  • Bloody or cloudy urine
  • Change in hearing
  • Dark urine
  • Difficult or painful urination
  • Earache
  • Fast heartbeat (tachycardia)
  • Frequent urge to urinate (polyuria)
  • General fatigue and weakness
  • Hives
  • Hoarseness
  • Irritation
  • Itching
  • Joint pain, stiffness, or swelling
  • Large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • Light-colored stools
  • Noisy breathing
  • Pain in the ears
  • Rash
  • Redness of the skin
  • Shortness of breath
  • Skin blisters
  • Swelling of the eyelids, face, lips, hands, or feet
  • Upper right abdominal or stomach pain
  • Yellow eyes and skin (jaundice)

Some side effects that may occur do not normally need medical attention. These may leave as your body becomes accustomed to treatment. 

Ask your doctor about ways to prevent or reduce some of these side effects.

Talk to your doctor if any of the following side effects continue or are bothersome, or if you have questions:

More Common

  • Abdominal or stomach pain or discomfort
  • Back pain
  • Difficulty moving
  • Gas with leaky bowel movements 
  • Inability to hold bowel movement
  • Increases in bowel movements
  • Loss of bowel control
  • Oily bowel movements
  • Oily spotting of underclothes

Less common:

  • Itching of the genital areas
  • Menstrual changes
  • Pain during sexual intercouse
  • Rectal pain or discomfort
  • Thick, white vaginal discharge with no or mild odor

Some patients may experience other side effects that are not listed. Check with your doctor if you notice any other side effects.

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