The most common orlistat side effects involve the bowel system. Orlistat causes a person to experience an increase in bowel movements and uncontrollable bowel movements as well. Other common orlistat side effects include fatty or oily stools, loose stools and oily spotting on underwear. In addition, a person might also suffer abdominal pain and rectal pain. These common side effects are actually normal reactions to orlistat and are signs that the medication is working correctly.
Serious orlistat side effects might occur, and if they do, they require immediate attention by a doctor; examples of serious side effects include severe allergic reaction, diarrhea and loss of appetite, in addition to nausea, extreme tiredness and vomiting. Symptoms due to allergic reaction include difficulty breathing, hives and swelling of the face and throat areas. Liver failure and pancreatitis are two conditions that might occur as a result of orlistat. Signs of these medical conditions can overlap some side effects of orlistat, such as loss of appetite for liver failure and nausea or vomiting for pancreatitis. Other signs of liver failure are dark urine, light-colored stools and jaundice while additional signs of pancreatitis are a fast heart rate and upper abdominal pain.
Orlistat itself is a lipase inhibitor that works by blocking fat from being absorbed by the body. Since the body does not absorb as much fat as it normally would, the fat leaves the body through waste, loosening stools and making them oily. As such, it makes bowel movements less predictable. For some people, orlistat side effects will go away after a few weeks of treatment, although for others, side effects will occur for as long as they take the medication. In general, the more fat foods contain, the more side effects occur, so a person taking orlistat should not indulge in overly fatty foods.
The purpose of orlistat is to help with weight loss. Available in both prescription and non-prescription form, orlistat is used in combination with a low-calorie, low-fat diet, as well as with exercise. The non-prescription form contains a lower-strength dosage than the prescription form so it causes fewer side effects. Non-prescription orlistat is not for those 18 years and under, while prescription orlistat is not for those between the ages of 12 and 18. A doctor might prescribe orlistat for overweight people with certain conditions such as diabetes, high blood pressure and high cholesterol.