Understand how orlistat, a drug that reduces fat absorption, works

Known to reduce the absorption of fat in the intestine, orlistat is used in the treatment of obesity. The drug, however, offers modest weight loss. Therefore, according to experts, it is more useful if combined with lifestyle changes and other therapies. Doctors also point out the improvement of blood glucose and cholesterol as benefits.

According to Cintia Cercato, endocrinologist and president of Abeso (Brazilian Association for the Study of Obesity and Metabolic Syndrome), the drug inhibits the action of lipases, enzymes that participate in the fat digestion process.

“When we eat fat, it needs to be broken down into smaller pieces to be absorbed. It is broken down by these intestinal lipases”, says Cercato.

Also according to the endocrinologist, when the drug inhibits the action of these enzymes, the fat is not broken down into smaller molecules, which makes its absorption difficult and causes part of it to be eliminated along with the feces.

According to experts, the drug is able to reduce the absorption of fat by 30%, which can lead to weight loss, but in a reduced form.

Cercato says that the modest result is due to the mechanism of action of the drug, since, unlike other drugs used in the treatment of obesity, orlistat does not act in the regulation of appetite.

“Obesity is a complex disease that is characterized by changes in the regulation of this energy balance of hunger and satiety. The fact that this medication does not act on these mechanisms makes its result modest”, he points out.

The professional points out that, like any drug to treat obesity, orlistat is indicated for patients who are classified as obese, with a BMI (body mass index) greater than or equal to 30, or overweight (BMI from 25 to 29.9 ), and who have some disease-related comorbidity. In addition, the use of drugs to treat obesity must be associated with changes in lifestyle, dietary reeducation and physical exercise, the basis for this type of treatment.

Cercato warns that orlistat can interfere with the absorption of fat-soluble vitamins important for the body, such as vitamins A and D. In addition, it can alter the effect of some medications, such as anticoagulants, and worsen the symptoms of patients with intestinal problems. Therefore, although a prescription is not necessary, the doctor reinforces that the medicine needs to be administered under the guidance of a specialist.

Endocrinologist Márcio Mancini, vice president of the obesity department at SBEM (Brazilian Society of Endocrinology and Metabology) and head of the obesity group at the Hospital das Clínicas da USP (University of São Paulo), says that the drug was made to be associated to an adequate diet.

“As orlistat reduces the absorption of a third of the dietary fat, if the individual eats a feijoada and takes the medicine, the amount of fat that will reach the end of the intestine will be very large. The individual loses control and has to run to the bathroom”, he exemplifies.

Mancini says that the medicine needs to be taken with the main meals of the day. Therefore, the patient must have an organized eating habit. “This is a drug that is to be taken at the meal where it will take effect. It is taken for breakfast, lunch and dinner.”

The specialist also emphasizes that orlistat is indicated to treat obesity, not for the simple reduction of measures. “To use the drug, the patient has to be at least overweight,” he says.

According to the doctor, studies show that, in addition to modest weight reduction, the drug has an impact on glucose and cholesterol.

“There’s an interesting study called Xendos that gave orlistat to patients with normal glucose and a group that had slightly altered glucose and followed these patients for 4 years. Those who took the drug developed less diabetes, showing a benefit over glucose,” he says.

“Another study with patients with high cholesterol showed a 17.6% reduction in bad cholesterol.”

Vanessa Prado, coloproctologist and physician at the Digestive System Specialties Center at Hospital Nove de Julho, says that the drug does not harm the body and is also used to treat constipation. The doctor says that it can, however, cause fecal incontinence, an effect that can be controlled through dosage.

“As it prevents the absorption of fat, the poop is extremely softened and full of it. Often the patient cannot hold it because they are smoother stools”, points out Prado.

According to her, the medication can be used for 6 to 9 months to compose an initial treatment aimed at constipation, but the ideal is to bet on the formation of a fecal cake rich in fibers and on the use of prokinetics, drugs that help in the bowel movement, to improve evacuation.

The endocrinologist Cercato reinforces that orlistat is a good aid in the treatment of obesity, but that it cannot be seen as a single solution.

“Obesity is an extremely complex disease that has many mechanisms involved. The treatment of a complex disease is also complex, it is not simple.”