Some people on alli® will experience GI side effects, which is expected since alli works by inhibiting about 25% of dietary fat. alli is half the strength of prescription Xenical® (orlistat 120 mg), and, as a result, has fewer GI events overall than Xenical®. In clinical trials, subjects on 120 mg withdrew due to GI adverse events at a rate of 5.4%—and at 60 mg it was only 3.2%.
The main treatment effect occurs when an individual eats a meal with too much fat while taking alli. Treatment effects may include:
- Loose or more frequent stools that may be hard to control
- An urgent need to go to the bathroom
- Gas with oily spotting
While excess fat that is excreted is not harmful, patients could be distressed by the experience. Treatment effects can be lessened if an individual sticks with reduced-calorie, low-fat meals that average 15 grams of fat per meal (or 30% fat or less). Diets may vary from 1,200 calories to 1,800 calories per day, so 15 grams is an average. Individuals need to be aware of hidden fat in food, so that they can lower the chance of having treatment effects.
Not all individuals will experience treatment effects, but those that do can reduce the likelihood of these effects by taking alli as directed and sticking with a reduced-calorie, low-fat diet. The alli starter pack includes portable reference guides and online support at myalli.com to help patients follow the program accurately. Some patients may experience treatment effects as they begin therapy until they learn to adjust their diet.