Orlistat: Weight Loss Medication Explained

Orlistat is a medication used for weight loss. In the United States, it is available in two forms: a lower-dose version sold over the counter under the brand name Alli, and a higher-dose prescription version sold as Xenical or generic orlistat.

Orlistat is used along with a reduced-calorie, lower-fat diet and regular physical activity. Whether it is appropriate depends on factors such as BMI, overall health, and other medical conditions.

Weight loss is crucial if you are overweight, as excess weight puts you at an increased risk of developing a range of health problems such as diabetes, high blood pressure, heart disease, and even some cancers. There is also a higher-strength version of orlistat that is only available on prescription.

Orlistat comes as a capsule and is usually taken three times a day with each main meal that contains fat. Take it during the meal or up to one hour afterward. If you skip a meal or the meal contains no fat, skip that dose of orlistat.

Orlistat can reduce the absorption of fat-soluble vitamins, including vitamins A, D, E, and K. For this reason, you should take a daily multivitamin that contains these vitamins. Take the multivitamin at least two hours before or after orlistat, such as at bedtime.

How long you take orlistat depends on which product you use, how well it is working, and whether you have side effects. If you are not losing weight or are unsure whether you should continue treatment, talk with your doctor or pharmacist.

Orlistat works by reducing fat absorption from your meals into your body. Orlistat inhibits enzymes in your digestive system called lipases that break down fat into components (called fatty acids and monoglycerides) which your digestive system then absorbs. The fat you have not broken down can’t be absorbed and instead passes out of your body in your stools. Orlistat can prevent about a quarter of the fat from your meals from being absorbed by your digestive system.

Do not take orlistat if you are allergic to orlistat or any of its ingredients, are pregnant, have chronic problems absorbing nutrients from food, or have cholestasis, a condition that affects the flow of bile from the liver.

Over-the-counter Alli is only approved for adults age 18 and older who are overweight. Talk with your doctor or pharmacist before taking orlistat if you are breastfeeding or take medicines such as cyclosporine or warfarin, because orlistat can interact with these medicines.

Speak with your doctor before taking orlistat if you have:

• kidney disease
• diabetes
• a thyroid condition
• epilepsy
• HIV

If you take any prescription, over-the-counter or herbal medicines, ask your doctor or pharmacist to check if they are safe to take alongside orlistat.

As with all medications, some people may experience side effects. Some common ones include flatulence, fatty or oily stools, oily spotting on your underwear, sudden bowel movements, and stomach pain. Eating lower-fat meals can help to reduce side effects. You should speak with your doctor or pharmacist if you are concerned about any side effects.