Pharmacology of Orlistat
Orlistat, classified as an anti-obesity agent, falls within the therapeutic category of medications designed to assist in weight control.
It is the hydrated form of lipstatin, a naturally occurring molecule, with its hydration enhancing its stability profile.
The mechanism of action involves acting as a potent reversible inhibitor of gastric and pancreatic lipases. Orlistat’s impact is localized within the gastrointestinal tract (GIT) lumen, where it effectively impedes the cleavage of triglycerides.
As a result, it averts the absorption of approximately 30% of ingested dietary fat, which then exits the body through feces.
This process yields a hypocaloric state, facilitating weight loss primarily through the reduction of visceral and subcutaneous fat.
Notably, the efficacy of orlistat is contingent on the presence of dietary fat, necessitating its intake alongside meals. Discontinuing orlistat usage swiftly restores normal fat absorption.
Uses of Orlistat
Orlistat serves a range of indications for long-term weight control, encompassing weight loss, weight maintenance, and the prevention of weight regain.
These benefits materialize when orlistat is paired with a moderately hypocaloric diet.
It is particularly applicable to patients classified as obese (with a body mass index, or BMI, greater than or equal to 30 kg/m²) or those categorized as overweight (BMI > 28 kg/m²) with associated risks such as diabetes, hypertension, and dyslipidemia.
In type 2 diabetic patients who are overweight or obese, orlistat, when combined with a mildly hypocaloric diet, contributes to improved glycemic control in conjunction with other antidiabetic agents.
Dosage of Orlistat
The recommended adult dosage of orlistat is 120 mg capsule, taken orally with each meal, either immediately before, during, or up to one hour after the meal.
Noteworthy is the requirement for patients to adhere to a nutritionally balanced and mildly hypocaloric diet while using orlistat.
Orlistat is deemed unsuitable for children under the age of 12.
Side effects of Orlistat
Potential side effects associated with orlistat usage include the following:
- Abdominal discomfort
- Fatulence
- Liquid stools
- Soft stools
- Rectal pain or discomfort.
The likelihood of experiencing these side effects is influenced by the dietary fat content, with higher fat intake correlating with an increased incidence of these symptoms.
Administration:
Orlistat is administered orally and should be taken as directed in accordance with the prescribed guidelines.
Pregnancy & Lactation
The use of orlistat during pregnancy and lactation is a subject with limited available data.
While the drug’s minimal systemic bioavailability suggests low risk, caution is advised due to the potential for maternal fat-soluble vitamin deficiency, which in turn could impact fetal development.
Pregnant women using orlistat are recommended to take a multivitamin supplement, ensuring a two-hour gap between drug intake and the supplement.
Contraindications of Orlistat
Orlistat is contraindicated in cases of known hypersensitivity to the drug or any of its ingredients.
Additionally, individuals with chronic malabsorption syndromes or cholestasis should avoid orlistat usage.