Orlistat Side Effects
Common Side Effects
Orlistat has been studied thoroughly in clinical trials. In these studies, side effects that occur in a group of people taking the drug are documented and are then compared to side effects that occur in another group of people not taking the medicine. This way, it is possible to see what side effects occur, how often they appear, and how they compare to the group not taking the medicine.
In these studies, side effects that affected the digestive system were common (as would be expected, based on how orlistat works). These orlistat side effects included:
- Oily spotting (uncontrolled anal oil seepage)
- Abdominal pain (stomach pain) or discomfort
- Gas with a small amount of oil or stool
- Fecal urgency (an urgent but controlled need to have a bowel movement)
- Fatty or oily stool
- Oily evacuation (bowel movements of just oil, without stool)
- Increased frequency of bowel movements
- Uncontrolled, spontaneous bowel movements (known as fecal incontinence).
Many of the side effects that affect the digestive tract can be avoided or reduced by decreasing the amount of fat in your diet. Because the drug decreases the absorption of fat, more fat stays in the digestive tract, causing many of the bothersome and sometimes embarrassing side effects of this medication. You are more likely to experience these side effects if you eat too much fat. As you continue to take the drug, you will learn how different foods and different amounts of fat affect you. In fact, in studies, these side effects occurred much less commonly in the second year of treatment. If you have consumed a meal that is high in fat and have taken orlistat, you may want to prepare for possible side effects.
Other common side effects with orlistat included:
- The flu
- A respiratory tract infection (such as the common cold)
- Back pain
- Menstrual irregularity
- Ear infection.