Orlistat Online UK

Orlistat is a reversible gastrointestinal lipase inhibitor that reduces the absorption of dietary fat by approximately 30%.

It acts locally in the gastrointestinal tract by binding to the active site of gastric and pancreatic lipases, preventing the hydrolysis of dietary triglycerides into absorbable free fatty acids.

The undigested fat is excreted in the faeces.

Orlistat is licensed for weight management in obese adults (BMI ≥30 kg/m²) or overweight adults (BMI ≥28 kg/m²) with associated risk factors, as an adjunct to a mildly hypocaloric, reduced-fat diet.

It is available as a prescription-strength 120 mg capsule (Xenical) and as an over-the-counter 60 mg capsule (Alli).

NICE recommends orlistat as the only currently available pharmacological option for weight management within a comprehensive programme including diet, exercise, and behavioural support.

In clinical trials, orlistat 120 mg three times daily produced mean weight loss approximately 2.7-3.4 kg greater than placebo over 12 months.

Treatment should be discontinued if less than 5% body weight is lost after 12 weeks of consistent use.

Orlistat also modestly improves glycaemic control and lipid profiles in overweight patients with type 2 diabetes.

Take one capsule with water immediately before, during, or up to one hour after each main meal. If a meal is missed or contains no fat, omit the dose. Do not take more than three capsules per day.

Follow a nutritionally balanced, mildly hypocaloric diet with approximately 30% of calories from fat. Distributing fat intake evenly across three meals reduces gastrointestinal side effects.

Take a daily multivitamin supplement containing fat-soluble vitamins (A, D, E, K) at bedtime or at least 2 hours before or after orlistat, as the drug reduces their absorption.

Maintain regular physical activity alongside dietary changes for optimal results.

Prescription strength (Xenical): 120 mg three times daily with meals.

OTC strength (Alli): 60 mg three times daily with meals.

No dose escalation is available or effective; doses above 120 mg three times daily do not provide additional benefit. No dose adjustment for elderly patients, hepatic impairment, or renal impairment.

Treatment duration is typically 6-12 months, subject to regular clinical review. Stop treatment after 12 weeks if less than 5% body weight loss has been achieved.

Orlistat may impair absorption of oral contraceptives during episodes of severe diarrhoea; additional barrier contraception is advised.

Side effects relate directly to the mechanism of action — impaired fat absorption.

Very common (≥1/10): Oily/fatty stools, oily rectal discharge (spotting), flatus with discharge, faecal urgency, increased defecation, steatorrhoea, abdominal pain or discomfort.

Common (≥1/100 to <1/10): Faecal incontinence, liquid stools, flatulence, soft stools, rectal pain, headache, upper respiratory tract infection, influenza, hypoglycaemia (in patients with type 2 diabetes), menstrual irregularities, anxiety, fatigue.

Uncommon (≥1/1,000 to <1/100): Abdominal distension, dental or gum disorder, rectal disorder.

Rare (≥1/10,000 to <1/1,000): Hepatitis, cholelithiasis, diverticulitis, pancreatitis, oxalate nephropathy (particularly in patients with chronic kidney disease or dehydration), severe allergic reactions (anaphylaxis, angioedema, bronchospasm, bullous eruption).

Gastrointestinal effects are the most frequent and can be substantially minimised by keeping dietary fat at or below 30% of total calorie intake per meal.

Fat-soluble vitamin (A, D, E, K) supplementation is recommended throughout treatment.

Orlistat may reduce the absorption of levothyroxine; separate dosing by at least 4 hours and monitor thyroid function when initiating or changing orlistat dose.

Anticoagulant (warfarin) effect may be altered due to reduced vitamin K absorption; monitor INR closely.

Rare cases of severe hepatotoxicity have been reported (MHRA Drug Safety Update); advise patients to discontinue and seek medical attention if jaundice, dark urine, pruritus, or right upper quadrant pain develop.

Oxalate nephropathy has been documented, particularly in patients with underlying renal impairment; maintain adequate hydration.

Ciclosporin absorption may be reduced; take ciclosporin 3 hours after orlistat and monitor levels closely.

Orlistat is contraindicated in chronic malabsorption syndrome, cholestasis, known hypersensitivity to orlistat or any excipient, pregnancy, and breastfeeding.

Concurrent ciclosporin use requires careful monitoring or avoidance. Patients with anorexia nervosa or bulimia nervosa should not take orlistat.