Orlistat

Please note: these are basic guidelines, refer to your doctor for a professional medical opinion.

Popular brand names:

Xenical

Drug group:

Anti-obesity drug

Prescription needed?

No

What does it do?

Orlistat is used in the treatment of obesity.

How does it work?

Orlistat blocks the action of lipase (enzyme produced by the stomach/pancreas). Less dietary fat is absorbed which results in reduced calorie uptake. The body then burns stored fat to provide energy.

Orlistat reduces fat absorption, therefore fat-soluble vitamins (A, D, E, and K) may become deficient.

How should it be used?

• Orlistat should only be used to lose weight in conjunction with healthy lifestyle measures including a well-balanced, calorie-controlled diet and exercise
• Do not take your dose if you miss a meal or if a meal contains no fat
• Vitamin supplements may be needed - take at least 2 hours before a dose or at bedtime

What is the typical dosage?

Your doctor will recommend a dosage tailored to your need, but typically:

• Capsules should be taken just before or during or up to 1 hour after each main meal
• 120mg up to 3xdaily (total 360mg daily)

How quickly will it start to work?

Within 30 minutes, excretion of excess faecal fat begins about 24–48 hours after the first dose. 
                  

How long will the effects last?

Orlistat is not absorbed, and continues to work as it passes through the intestines. Faecal fat content returns to normal in 48–72 hours after stopping the drug.

When should I stop using it?

The drug can be safely stopped as soon as no longer needed.  

Is it safe for prolonged use?

Orlistat treatment should be stopped if you have not lost 5% of your body weight after 12 weeks, or at least 10% of your body weight over the first 6 months.

Once these minimum weight loss requirements have been met, the drug may be continued until target weight is reached, for a maximum of 2 years. There may be gradual weight gain when treatment is stopped.

What are the possible side effects?

The following have been reported:

• Common: liquid/oily stools, faecal urgency, flatulence, abdominal/rectal pain, headache, menstrual irregularities, anxiety, fatigue, nausea, infections (e.g. respiratory infections), hypoglycaemia (low blood sugar)
• Report to your doctor before taking your next dose if you experience: any severe side effects

What other considerations are important?

Dosage may be adjusted by your doctor under certain conditions.

• Certain health problems: diabetes, chronic malabsorption syndrome, gallbladder/liver problems
• Other medicines: ciclosporin, oral anticoagulants, amiodarone, anti-epileptics, acarbose, lipid-lowering drugs
• Pregnancy and breast-feeding: Safety not established
• Children: Generally not recommended in <18 years
• Over 60: No special problems
• Driving and hazardous work: No special problems
• Alcohol: No special problems