Alli (orlistat) is an over-the-counter medication used to help people lose weight. Studies have shown that Alli can help people lose more weight than dieting alone. The weight loss drug is intended for overweight adults ages 18 and older who also follow a reduced-calorie, low-fat diet.
A stronger dose of the same active ingredient in Alli is available by prescription and is sold under the brand name Xenical. Xenical may also be recommended after weight loss surgery to help patients keep off the lost pounds.
How Does Alli Work?
Alli belongs to a class of drugs called lipase inhibitors. It blocks the intestines from absorbing about 25% of the fat that you eat. Fats that aren’t absorbed leave your body through bowel movements. Some data suggest that Alli helps reduce the amount of a particularly dangerous type of belly fat called visceral fat, which has been linked to type 2 diabetes, high blood pressure, heart disease, and stroke.
Is Alli Right for Me?
If you’re overweight, and dieting and exercise haven't worked for you, talk to your doctor about a weight management program that involves medication. But remember, you still must follow a healthy lifestyle that involves regular exercise and eating right.
To determine if you’re overweight, you can calculate your body mass index (BMI) using your height and weight information. A BMI of 18.5 to 24.9 is considered a healthy weight. A BMI of 25 to 29.9 is considered overweight.
How Do I Take Alli?
Alli comes in capsule form. It’s taken by mouth three times a day, either with a meal that contains a little bit of fat, or up to one hour afterward. If you eat a no-fat meal, your doctor may tell you to skip your dose. Never take more medicine than recommended.
It’s important to follow a low-calorie, low-fat diet while taking this medication. If you eat a lot of fatty foods, even just one high-fat meal like a greasy burger, you’re more likely to have uncomfortable digestive side effects. Choose lean cuts of meat and low-fat dairy products. In general, no more than 30% of your calories at each meal should come from fat.
You’ll also need to take a daily multivitamin that contains vitamins A, D, E, K, and beta carotene while on this drug. The drug's fat-blocking properties also make it more difficult for your body to absorb fat-soluble vitamins. Do not take vitamins and Alli at the same time of the day.
When Shouldn’t I Take Alli?
Always tell your doctor about all the medications you’re taking. Alli can interact with certain drugs, affecting their levels or how they work in your body, which could lead to life-threatening consequences. Check with your doctor if you’re taking warfarin (a blood thinner), diabetes or thyroid medications, or other weight loss drugs. In some cases, your dosages may need to be adjusted.
Don’t take Alli if:
- You’ve had an organ transplant. Alli is known to interfere with drugs used to prevent transplant rejection.
- You’re taking cyclosporine.
- You’re not overweight.
- You’re pregnant or breastfeeding.
Side Effects of Alli
Loose stools and other bowel movement changes are the most common side effects of Alli. Symptoms typically occur during the first few weeks of treatment and then go away. However, they may continue.
Tell your doctor if you have any of the following symptoms and they become severe or do not go away:
- Difficulty controlling bowel movements
- Loose, frequent stools
- Oily or fatty stools
- Oily spots on undergarments
- Stomach or rectum pain
- Passing gas more often
- Urgent need to have a bowel movement
- Changes in your menstrual cycle
Emergency Side Effects of Alli
Call 911 or your doctor immediately if you develop any of these symptoms:
- Difficulty breathing
- Difficulty swallowing
- Hives or itching
- Stomach pain that is severe or does not go away
Alli has been linked to severe liver injury in rare cases, though it has mostly occurred in those taking the prescription-strength dose (Xenical). Stop taking Alli and call your doctor immediately if you develop any of these possible signs of liver damage: