Mechanism of action of Orlistat used to treat obesity is which of the following?
**Core Concept**
Orlistat is a medication used to treat obesity by inhibiting the absorption of dietary fats. It acts on the gastrointestinal tract to reduce fat digestion and absorption, thereby promoting weight loss.
**Why the Correct Answer is Right**
The mechanism of action of Orlistat involves the inhibition of gastric and pancreatic lipases, enzymes responsible for breaking down triglycerides into fatty acids and glycerol. Orlistat binds to the active site of these lipases, preventing them from hydrolyzing triglycerides into fatty acids and glycerol, which are then absorbed by the body. This results in a reduction in the absorption of dietary fats, leading to weight loss.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Orlistat does not work by increasing satiety or reducing hunger, which are effects of other weight loss medications like phentermine.
**Option B:** This option is incorrect because Orlistat does not work by increasing metabolic rate or thermogenesis, which are effects of other weight loss medications like ephedrine.
**Option C:** This option is incorrect because Orlistat does not work by blocking the absorption of carbohydrates or proteins, which are effects of other weight loss medications like acarbose.
**Clinical Pearl / High-Yield Fact**
It's essential to note that Orlistat can cause gastrointestinal side effects like oily stools, flatulence, and fecal urgency due to the undigested fats in the stool.
**Correct Answer: C. Inhibition of gastric and pancreatic lipases.**