Orlistat; A review

Orlistat is a fat blocking agent as it inhibits the dietary fat absorption in the body from GIT. It reduces 30% absorption of the dietary fat which can cause 200kcal deficit in caloric intake in 24hrs.

Mechanism of action

It causes inhibition of fat absorption by inhibiting fat metabolism needed enzymes like gastric and pancreatic lipases. These enzymes hydrolyze or breakdown triglycerides into absorbable fats. Absence of these enzymes causes less absorption of fat from gut helping to lose weight. Orlistat does not appear in the blood so its own side-effects are not systemic. Main route of elimination is by feces.

Efficacy

In a clinical trial Orlistat caused 5% decrease in the weight in 40-50% subjects and 10% in the 15-30% users. So efficacy varies from subject to subject. Not all but many of the users started gaining weight after the treatment was stopped but there was a considerable decrease in the Type 2 diabetes incidence among the subjects.

Contraindications

It is not advised in following conditions • Mal-absorption • Pregnancy and Breast feeding • Any gall bladder disease • Some kidney diseases In all of above mentioned conditions use of Orlistat can be hazardous.

Criteria for prescription

National Institute of Clinical Excellence recommends use of Orlistat in following circumstances. • Patient should have lost at least 2.5 kg in a month before starting drug therapy • If the patient has BMI over 30 • If the age of patient is between 18 and 75 • If there is less than 5% weight loss stop treatment • If there is less than 10% weight loss stop treatment • Don’t treat with Orlistat over 24 months period

Side-effects

The following unwanted effects can be seen with Orlistat use • Mal-absorption • Loose stools • Oily spotting • Flatus • Fecal urgency • Mal-absorption of fat soluble vitamins

Brand name

Orlistat is being marketed under the brand name of Xenical by Roche in UK Australia and New-Zealand. Now it is also being launched in USA by Glaxo Smith Kline in the brand name of Alli.

Dosage

It is available in 60mg and 120mg capsules.