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Orlistat information from DrugsUpdate  

See Available Brands of Orlistat in India

P - Caution when used during pregnancy
L - Contraindicated in lactation

Orlistat (marketed as a prescription under the trade name Xenical by Roche or over-the-counter as Alli by GlaxoSmithKline), also known as tetrahydrolipstatin, is a drug designed to treat obesity. Its primary function is preventing the absorption of fats from the human diet, thereby reducing caloric intake. It is intended for use in conjunction with a physician-supervised reduced-calorie diet. Orlistat is the saturated derivative of lipstatin, a potent natural inhibitor of pancreatic lipases isolated from the bacterium Streptomyces toxytricini. However, due to simplicity and stability, orlistat rather than lipstatin was developed into an anti-obesity drug.



Orlistat is a reversible gastric and pancreatic lipase inhibitor. It exerts antiobesity effects by limiting the absorption of dietary fats through inhibition of triglyceride hydrolysis. It does not exert appetite suppressant effects.


24-48 hours.


48-72 hours.


Minimally absorbed (oral).


Metabolised to inactive metabolites within the GI wall.

Mainly via faeces (83% as unchanged drug).

Orlistat Indications / Orlistat Uses

The amount of weight loss achieved with orlistat varies. In one-year clinical trials, between 35.5% and 54.8% of subjects achieved a 5% or greater decrease in body mass, although not all of this mass was necessarily fat. Between 16.4% and 24.8% achieved at least a 10% decrease in body mass. After orlistat was stopped, a significant number of subjects regained weight—up to 35% of the weight they had lost.

The incidence of type 2 diabetes in an obese population over four years is decreased with orlistat (6.2%) compared to placebo (9.0%). Long-term use of orlistat also leads to a modest reduction in blood pressure (mean reductions of 2.5 and 1.9 mmHg in systolic and diastolic blood pressure respectively).

Orlistat Adverse Reactions / Orlistat Side Effects

Faecal urgency and incontinence, flatulence, fatty stools or discharge, increased defecation; headache, anxiety, fatigue, menstrual irregularities; abdominal pain/discomfort.

Potentially Fatal: Anaphylaxis; angioedema.


Absorption of fat-soluble vitamins and other fat-soluble nutrients is inhibited by the use of orlistat. A multivitamin tablet containing vitamins A, D, E, K, and beta-carotene should be taken once a day, at bedtime, when using orlistat.

Orlistat is listed as having a "Potential Signal of Serious Risk" of liver toxicity, meaning that a potential risk of liver toxicity was identified based on reports to the FDA Adverse Event Reporting System between October and December 2008.

Special Precautions

Distribute daily intake of fat over 3 main meals. Fat-soluble vitamins supplements may be required during long-term therapy. Discontinue use if 5% body wt loss is not achieved during the first 12 wk. History of hyperoxaluria or calcium oxalate nephrolithiasis. DM. Pregnancy.

Other Drug Interactions

May decrease absorption of oral fat-soluble vitamins, amiodarone, propafenone. May decrease plasma levels of ciclosporin. May alter the effects of warfarin (monitor INR). May elevate plasma levels of pravastatin.

Other Interactions

Information Not Available


Adult: 120 mg tid with each main meal containing fat; omit dose if meal is occasionally missed or has no fat.
Child: ≥12 years: 120 mg tid with each main meal containing fat; omit dose if meal is occasionally missed or has no fat.


Should be taken with food. (Take immediately before or during or up to 1 hr after each main meal. If a meal is missed or contains no fat, the dose may be omitted.)

List of Contraindications

Orlistat and Pregnancy

Caution when used during pregnancy

Category B: Either animal-reproduction studies have not demonstrated a foetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the 1st trimester (and there is no evidence of a risk in later trimesters).

Orlistat and Lactation

Contraindicated in lactation

Orlistat and Children

Safety and efficacy not established in children younger than 12 years of age.


Safety and efficacy not established.

Orlistat and Geriatic

Information Not Available

Orlistat and Other Contraindications

Chronic malabsorption syndrome. Cholestasis. Lactation.


Store at 15-30°C (59-86°F).

Lab interference

Store at 15-30°C (59-86°F).

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