Orlistat

Orlistat is a drug used to treat obesity that is marketed under several trade names, including Xenical. Its main purpose is to reduce calorie intake by acting as a lipase inhibitor, which stops fats from the human diet from being absorbed. It is meant to be used in conjunction with a reduced-calorie diet under the supervision of a healthcare professional.

Lipstatin, a strong natural inhibitor of pancreatic lipases that was isolated from the Streptomyces toxytricini bacteria, is the saturated derivative of orlistat. However, orlistat was selected over lipstatin for development as an anti-obesity medication because of its relative stability and simplicity.

What is orlistat?

By blocking some of the fat you eat, orlistat prevents your body from absorbing it.

Orlistat is used to assist people in losing weight or lowering their chance of gaining it back. This medication must be taken in conjunction with a lower-calorie diet and more exercise. Only people who are overweight or obese should take orlistat.

The prescription-strength version of orlistat is called Xenical. There is no prescription required to purchase the Alli brand.

Orlistat has a clear but limited ability to help in weight loss. According to data compiled from clinical trials, individuals who use orlistat together with lifestyle changes like diet and exercise lose roughly 2-3 kg (4-7 lb.) more than those who do not take the medication over one year. Whether as a result of weight loss or other side effects, orlistat also slightly lowers blood pressure and seems to delay the onset of type 2 diabetes. It lowers the prevalence of type II diabetes in obese individuals by about the same proportion as lifestyle modifications.

Despite its advantages, orlistat is known to cause gastrointestinal side effects, sometimes known as treatment effects, such as steatorrhea (loose, oily stools). However, they are the most commonly reported side effects of the medication and diminish over time. Orlistat is accessible for purchase without a prescription in the US, the EU, and Australia. Public Citizen, a consumer advocacy group, consistently opposed over-the-counter approval in the US on the grounds of efficacy and safety. In certain nations, generic versions of orlistat are accessible. Since 2000, it has been classified as an S3 drug in Australia, meaning that a pharmacist can sell it without a prescription.

Mechanism of action

Orlistat functions by preventing the breakdown of triglycerides in the intestine by the enzymes pancreatic and gastric lipases. Triglycerides from food are eliminated unaltered when lipase activity is inhibited because they are not digested into absorbable free fatty acids. After an oral dosage, the main impact of orlistat is local lipase inhibition in the GI tract; only trace amounts are absorbed systemically. The feces are the main method of excretion.

Additionally, it has been discovered that orlistat inhibits the thioesterase domain of fatty acid synthase (FAS), an enzyme that promotes the growth of cancer cells but not healthy cells. Orlistat’s use as a strong anticancer drug, however, may be hampered by possible adverse effects such as limited absorption or inhibition of other cellular off-targets. One profiling investigation used a chemical proteomics technique to find orlistat’s off-targets as well as novel cellular targets. Additionally, orlistat may be effective against the parasite Trypanosoma brucei.

About 30% of dietary fat cannot be absorbed when using orlistat.

Medical applications

The medication orlistat is used to treat obesity. When using orlistat, different people lose different amounts of weight. Between 35.5% and 54.8% of participants in one-year clinical studies saw a 5% or more reduction in body mass, albeit not all of this mass was fat. At least a 10% reduction in body fat was attained by 16.4% to 24.8%.

A considerable portion of the participants gained back up to 35% of their weight after stopping orlistat. It lowers the prevalence of type II diabetes in obese individuals by about the same proportion as lifestyle modifications. Additionally, long-term orlistat use results in a very slight drop in blood pressure.

For what purpose is orlistat used?

People who are overweight or obese are frequently helped to lose weight by taking orlistat. Your healthcare professional may prescribe orlistat for additional conditions.

Contraindications

Orlistat should not be used in the following circumstances:

• Malabsorption
• Orlistat sensitivity decreased gallbladder function (e.g., following cholecystectomy)
• Breastfeeding and pregnancy
• Fatigue and Anorexia
• Be careful while dealing with pancreatic disease, liver impairment, and bile duct obstruction.

Warnings

If you are pregnant, avoid taking orlistat.

If you have a digestive disease, which is characterized by problems with food absorption, you should not use this medication. If you are pregnant or have gallbladder issues, you shouldn’t use Xenical. If you are underweight, have received an organ transplant, or take cyclosporine, avoid using Alli.

Orlistat is merely one component of a comprehensive therapy plan that also entails weight management, exercise, and food. You should have the same amount of fat, protein, and carbs each day across all of your meals. Pay strict attention to your exercise, medicine, and nutrition regimens.

Stay away from a diet heavy in fat. When using orlistat with high-fat meals, you run the chance of experiencing unpleasant side effects in your intestines or stomach.

Before using this medication

If you have malabsorption syndrome (a condition in which the body is unable to effectively absorb food and nutrients), are pregnant, or have an allergy to orlistat, you should avoid using it.

Additionally, you should avoid using Xenical if you have:

• gall bladder problem; or
• if you’re expecting a child.

Avoid using Alli if:

• You’re not overweight.
• You’ve received an organ transplant.
• Cyclosporine is what you’re taking.

Tell your doctor if you have ever experienced any of the following to ensure that orlistat is safe for you:

• kidney stones
• gallbladder diseases;
• pancreatitis;
• thyroid conditions;
• liver disease;
• renal disease; or
• The transplantation of organs; or
• a disorder of eating (bulimia or anorexia).

If you are pregnant, avoid using orlistat. Even if you are overweight, losing weight during pregnancy is not advised. If you get pregnant, stop taking this medication and notify your doctor immediately.

Certain vitamins may be more difficult for your body to absorb if you take orlistat. You should take these vitamins if you are nursing a baby. If you are nursing a newborn, do not take this medication without first seeing your doctor.

Anyone under the age of twelve is not permitted to use Xenical. Don’t give Alli to anyone younger than eighteen.

How is orlistat to be taken?

Follow the directions on the label or as your doctor prescribes when taking orlistat. Never use more or less than is advised, or for longer than is advised.

Orlistat should never be given to someone else, especially if they have a history of eating disorders.

Examine all of the patient data, prescription instructions, and instruction manuals that you have been given. Ask your doctor or pharmacist any questions you may have.

Typically, orlistat is taken three times a day with each major meal that includes fat (no more than 30% of the meal’s calories). The medication can be taken with food or up to an hour after eating.

If you consume a fat-free meal or skip a meal altogether, you should skip your dose for that meal.

You shouldn’t consume more than 30% of your daily calories from fat in your diet. For instance, no more than 360 of the 1200 calories you consume each day should come from fat.

Every food item you eat should have a label that you read, with particular attention to how many servings each container contains. You can create a healthy eating plan with the assistance of your physician, dietitian, or nutrition counselor.

Orlistat is merely one component of a comprehensive treatment plan that also consists of exercise and diet. You should have the same amount of fat, protein, and carbs each day across all of your meals. Pay strict attention to your exercise, medicine, and nutrition regimens.

You might need to take a vitamin and mineral supplement while taking orlistat since it can make it more difficult for your body to absorb some vitamins. Observe your physician’s advice regarding the kind of supplement you should use. Take the supplement at least two hours before or after taking orlistat or right before bed.

Keep out of direct sunlight, heat, and moisture, and store at room temperature. Don’t open the bottle. Once the medication label’s expiration date has passed, dispose of any unused orlistat.

Side effects of orlistat

If you have any of the following symptoms of an orlistat allergic reaction: hives, trouble breathing, or swelling of your face, lips, tongue, or throat, get emergency medical attention.

Call your doctor right away and stop taking orlistat if you have:

• extreme abdominal pain;
• severe lower back pain;
• Urinating is painful or difficult, and there may be blood in the urine.
• Symptoms of kidney disease, such as low or absent urination, ankle or foot edema, fatigue, or dyspnea; or
• Symptoms of liver disease, such as jaundice (yellowing of the skin or eyes), dark urine, clay-colored feces, nausea, upper stomach pain, itching, fatigue, and loss of appetite.

The fat-blocking activity of orlistat is the source of its common adverse effects. These indicate that the medication is doing its job. As you continue taking this medication, these adverse effects, which are typically transient, may diminish:

• fatty or oily stools;
• oily patches in your undergarments;
• Oil in your stool that is either orange or brown;
• oily and gaseous discharge;
• loose stools, sudden feelings to use the restroom, or a difficulty to regulate bowel motions;
• a higher frequency of bowel motions; or
• nausea, rectal pain, and stomach pain.

Information on dosage

Normal Adult Obesity Dosage:

Take 120 milligrams three times a day with each fat-containing main meal. The dosage can be taken either during the meal or within an hour after finishing it.

Normal Dosage for Obesity in Children:

For those aged 12 and up, take 120 mg three times a day with each main meal that contains fat. The dosage can be taken either during the meal or within an hour after finishing it.

What occurs if I don’t take my dose?

As soon as you remember, but no later than an hour after eating, take the missed dose. Skip the missed dose and take the medication at your next regularly scheduled time if it has been more than an hour since your last meal. Never take more medication to make up for a missed dosage.

What to Avoid

Stay away from high-fat meals to prevent unpleasant intestinal or stomach side effects.

Avoid taking cyclosporine three hours before or three hours after taking orlistat if you also take it.

Avoid taking levothyroxine (like Synthroid) four hours before or four hours after taking orlistat if you also take it.

Which medications will interact with orlistat?

If you also take any of the following medications, ask your doctor or pharmacist if taking orlistat is safe for you.

• Amiodarone
• cyclosporine
• insulin or diabetic medication taken orally;
• HIV or AIDS drugs;
• Medication for seizures (particularly if this medication makes your seizures worse);
• a dietary supplement containing vitamin E or beta-carotene; or
• A blood thinner, such as Jantoven, Coumadin, or Warfarin.

This is not an exhaustive list. Orlistat may interact with vitamins, herbal supplements, prescription and over-the-counter medications, and other medications. This drug guide does not provide a list of all potential interactions.

FAQs

Reference

• Orlistat: Uses, side effects, interactions, pictures, warnings & dosing – WebMD. (n.d.). https://www.webmd.com/drugs/2/drug-17220/orlistat-oral/details
• Orlistat. (2024, June 24). https://patient.info/healthy-living/obesity-overweight/orlistat-weight-loss-medicine
• Wikipedia contributors. (2025b, January 9). Orlistat. Wikipedia. https://en.wikipedia.org/wiki/Orlistat
• Orlistat: Uses, Dosage & Side Effects. (n.d.). Drugs.com. https://www.drugs.com/orlistat.html