Orlistat

Orlistat Medication Overview

Orlistat is a medication designed to treat obesity by preventing the absorption of fats from the human diet, thereby reducing caloric intake. It is intended for use in conjunction with a physician-approved reduced-calorie diet, exercise, and behavior modification program.

Chemical Composition and Form

Orlistat is a saturated derivative of lipstatin, a potent natural inhibitor of pancreatic lipases. The medication is typically available in capsule form, with each capsule containing 120 mg of the active ingredient.

Pharmacodynamic Properties

Orlistat exerts its therapeutic effect by forming a covalent bond with the serine residue of the active gastric and pancreatic lipases in the lumen of the stomach and small intestine. This inactivation prevents hydrolysis of dietary fat in the form of triglycerides into absorbable free fatty acids and monoglycerides.

Pharmacokinetic Considerations

As a lipase inhibitor, Orlistat is minimally absorbed into the bloodstream, and its systemic exposure is low. The primary route of elimination is through the feces. Orlistat’s pharmacokinetic profile is not altered by age, race, or kidney function.

Indications and Usage

Orlistat is indicated for weight management including weight loss and weight maintenance when used alongside a reduced-calorie diet. It is also indicated to reduce the risk for weight regain after prior weight loss. It is suitable for use in adults and children aged 12 years and above.

Dosage and Administration

The recommended dose of Orlistat is one 120 mg capsule three times a day with each main meal containing fat. The medication can be taken either during the meal or up to an hour after the meal. If a meal is missed or contains no fat, the dose of Orlistat can be omitted.

Missed Dose Instructions

If a dose is missed, it should be taken within an hour of the meal to ensure the drug is present in the gut at the time of fat intake. If more than an hour has passed since the last meal, the missed dose should be skipped.

Dietary Considerations

Patients should adhere to a nutritionally balanced, reduced-calorie diet with approximately 30% of calories from fat. Daily intake of fat, carbohydrate, and protein should be distributed over three main meals.

Drug Interactions

Orlistat may interact with fat-soluble vitamins (A, D, E, K) and other medications such as cyclosporine, levothyroxine, and antiepileptic drugs. A multivitamin containing these vitamins should be taken at least two hours before or after the administration of Orlistat.

Adverse Reactions and Side Effects

Common side effects of Orlistat include gastrointestinal issues such as fatty or oily stool, increased defecation, and possible incontinence. These effects may result from the unabsorbed fats passing through the digestive system.

Specific Population Considerations

There are no adequate studies of Orlistat in pregnant women, and it is not recommended for use during pregnancy. Weight loss is also not recommended during pregnancy, even if the patient is overweight or obese. The safety and effectiveness in pediatric patients below the age of 12 have not been established.

Monitoring Parameters

Patients using Orlistat should have their body weight monitored regularly, as well as periodic assessments of their diet and exercise compliance. Additionally, a multivitamin status should be monitored, especially for fat-soluble vitamins.

Storage and Stability

Orlistat capsules should be stored at room temperature away from moisture and heat. Keep the medication in a secure place out of the reach of children.

Dispensing Instructions

It is crucial that Orlistat is dispensed with the patient medication guide, which provides important information regarding its use and potential side effects. Pharmacists should ensure that the guide is given to each patient receiving the medication.

Disposal of Unused Medication

Patients should be advised on proper disposal of unused or expired Orlistat, which includes utilizing community drug take-back programs or following specific disposal instructions outlined in the medication guide, not via household waste or wastewater.