orlistat at a glance
Medicine class
Peripherally acting gastrointestinal lipase inhibitor.
Main role
Weight management alongside dietary and lifestyle changes.
Meal link
Taken around a fat-containing main meal; omit it if the meal is missed or contains no fat.
Where it acts
Acts mainly within the stomach and small intestine, with minimal absorption into the bloodstream.
What is orlistat used for?
The selected Xenical product is licensed with a mildly reduced-calorie diet for adults who meet its weight-related eligibility criteria.
Obesity with a body mass index of at least 30 kg/m².
Overweight with a body mass index of at least 28 kg/m² and associated risk factors.
How does orlistat work?
Orlistat blocks gastric and pancreatic lipases, the enzymes that break dietary triglycerides into absorbable components. Some dietary fat remains unabsorbed and passes into the stools; this also explains many gastrointestinal effects.
orlistat preparations and strengths
Capsule
Route: Oral
Strengths: 60 mg, 120 mg
How to take orlistat
Swallow the capsule with water around a main meal, following the dispensing label. A nutritionally balanced diet with fat spread across meals helps reduce troublesome bowel effects.
Omit the capsule if the meal is missed or contains no fat.
Very high-fat meals can increase oily stools, urgency and related effects.
If a multivitamin is recommended, separate it from orlistat as directed by the product information.
orlistat side effects
Common or expected effects
- Fatty or oily stools and oily spotting
- Wind, sometimes with oily discharge
- Urgent, frequent, loose or liquid stools
- Abdominal pain or discomfort
- Faecal leakage
- Headache
- Low blood glucose in people with type 2 diabetes
Get urgent medical advice
- Anaphylaxis or angioedema
- Persistent severe abdominal or back pain suggesting pancreatitis
- Jaundice, dark urine or other symptoms of hepatitis
- Severe or persistent rectal bleeding
- Blistering skin eruptions
- Symptoms of oxalate kidney injury or renal failure
orlistat in pregnancy
Orlistat is not routinely used during pregnancy because clinical pregnancy data are lacking and intentional weight loss is generally inappropriate. Anyone who becomes pregnant while taking it should contact their prescriber rather than making assumptions about fetal risk.
orlistat while breastfeeding
The selected Xenical product is contraindicated during breastfeeding because its excretion into human milk is not established. Although systemic absorption is minimal, product-specific licensing should guide practice and alternatives should be discussed with a prescriber.
orlistat interactions
Orlistat can alter the absorption or clinical control of several medicines and nutrients. Review all prescribed, pharmacy and complementary products before use.
Ciclosporin
May lower ciclosporin concentrations and reduce immunosuppression; the combination is not recommended, and specialist-level monitoring is required if unavoidable.
Warfarin and other oral anticoagulants
Anticoagulant control may change, so coagulation monitoring is required.
Acarbose
Concurrent use should be avoided because interaction studies are unavailable.
Common questions about orlistat
Answers are fully visible for fast scanning and source review.
Why does orlistat cause oily stools?
It prevents some dietary fat from being broken down and absorbed, so unabsorbed fat passes into the stools.
Does orlistat suppress appetite?
No. It acts mainly in the digestive tract to reduce fat absorption rather than directly reducing appetite.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.