Orlistat is a lipase inhibitor medication approved for weight management in adults with a body mass index (BMI) of 30 or greater, or 27 or greater with associated risk factors such as hypertension, diabetes, or dyslipidemia. It functions by inhibiting gastric and pancreatic lipases, enzymes responsible for the hydrolysis of dietary triglycerides into absorbable free fatty acids and monoglycerides. This results in approximately 30% reduction in fat absorption, supporting a calorie-controlled diet and sustainable weight loss when used as part of a comprehensive weight management program under medical supervision.

Features

• Contains orlistat as the active pharmaceutical ingredient
• Available in 60 mg (over-the-counter) and 120 mg (prescription-only) formulations
• White to off-white hard gelatin capsules
• Each dose taken with fat-containing meals
• Requires concomitant reduced-calorie diet
• Not systemically absorbed; acts locally in the gastrointestinal tract

Benefits

• Promotes clinically significant weight loss when combined with dietary modification
• Reduces absorption of dietary fats by approximately one-third
• Helps improve obesity-related comorbidities including glycemic control and lipid profiles
• Supports long-term weight maintenance when used as part of a comprehensive lifestyle intervention program
• Provides objective biochemical feedback mechanism through fat malabsorption effects
• May reduce cardiovascular risk factors associated with obesity

Common use

Orlistat is indicated for obesity management in adults with BMI ≥30 kg/m², or ≥27 kg/m² with comorbidities such as hypertension, type 2 diabetes, or dyslipidemia. It is used adjunctively to a reduced-calorie diet and should be incorporated into a comprehensive weight management program that includes nutritional education, increased physical activity, and behavioral modification. Treatment is typically initiated after other non-pharmacological approaches have proven insufficient, with continuation dependent on weight loss efficacy and tolerability.

Dosage and direction

The recommended dosage is one 120 mg capsule taken three times daily with each main meal containing fat (up to 30% of calories from fat). If a meal is missed or contains no fat, the dose should be omitted. The capsule should be taken during the meal or up to one hour after eating. Maximum daily dosage should not exceed 360 mg (three capsules). Treatment should be discontinued if no clinically meaningful weight loss (≥5% of baseline body weight) occurs within 12 weeks.

Precautions

Patients should maintain a nutritionally balanced, reduced-calorie diet with approximately 30% of calories from fat to minimize gastrointestinal adverse effects. Higher fat intake may increase the likelihood of gastrointestinal events. Supplemental multivitamins containing fat-soluble vitamins (A, D, E, K) should be taken at least 2 hours before or after orlistat administration. Use with caution in patients with history of hyperoxaluria or calcium oxalate nephrolithiasis. Monitor for signs of liver injury, although causal relationship remains uncertain.

Contraindications

Chronic malabsorption syndrome, cholestasis, known hypersensitivity to orlistat or any component of the formulation, pregnancy, and breastfeeding. Not recommended for use in pediatric patients or those with organ transplant receiving cyclosporine therapy. Contraindicated in patients with anorexia nervosa or bulimia. Should not be used concomitantly with acarbose or other weight loss products.

Possible side effects

Gastrointestinal effects are most common due to the mechanism of action: oily spotting, flatus with discharge, fecal urgency, fatty/oily stool, oily evacuation, increased defecation, and fecal incontinence. These effects are generally mild to moderate, decrease with continued use, and are associated with dietary fat content. Other reported effects include abdominal pain/discomfort, nausea, infectious diarrhea, rectal pain/discomfort, tooth/gum disorder, headache, upper respiratory infection, back pain, and menstrual irregularity.

Drug interaction

Orlistat may reduce absorption of fat-soluble vitamins and beta-carotene. May decrease plasma levels of amiodarone, cyclosporine, levothyroxine, antiepileptic drugs, and oral contraceptives. Patients taking these medications should separate administration by at least 2 hours. Concurrent use with warfarin requires close monitoring of INR due to potential effects on vitamin K absorption. May potentiate effects of pravastatin. Avoid concomitant use with other weight loss agents.

Missed dose

If a dose is missed, it should be skipped and the regular dosing schedule resumed with the next meal. Do not double the dose to make up for a missed administration. The medication is only effective when taken with meals containing dietary fat, making timing relative to food intake more critical than strict temporal scheduling.

Overdose

Cases of overdose have reported increased incidence of gastrointestinal adverse effects. There is no specific antidote. Treatment should be symptomatic and supportive. Medical attention should be sought if severe gastrointestinal symptoms occur or if large quantities have been ingested. Given the minimal systemic absorption, systemic toxicity is unlikely. Maintain hydration and consider short-term fat-restricted diet to mitigate gastrointestinal effects.

Storage

Store at room temperature between 15-30°C (59-86°F). Keep container tightly closed and protect from moisture and light. Keep out of reach of children. Do not use after expiration date printed on packaging. Capsules should remain in original container with desiccant to maintain stability.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Orlistat should only be used under appropriate medical supervision. Individual results may vary. Patients should consult with a healthcare professional before starting any weight management medication to determine appropriate treatment based on complete medical history, current medications, and overall health status. Not all patients will experience significant weight loss, and lifestyle modifications remain fundamental to successful weight management.

Reviews

Clinical trials demonstrate that orlistat plus diet produces significantly greater weight loss than placebo plus diet at 1 year (mean difference approximately 2.9 kg). Approximately 35-55% of orlistat-treated patients achieve ≥5% weight loss from baseline compared to 15-35% with placebo. Maintenance studies show significantly better weight maintenance with continued orlistat treatment compared to placebo after initial weight loss. Real-world evidence supports these findings, though gastrointestinal side effects remain the primary reason for discontinuation in approximately 5-10% of patients.