Orlistat (Xenical) is a drug introduced in 2000 to treat significant obesity. It acts by preventing the absorption of fat from the intestine.
Common side effects include diarrhoea (worse if fat eaten), flatulence, liquid faeces and headache.
It should be used with caution in pregnancy and children, with peptic ulcers, psychiatric disturbances, adhesions in belly, kidney stones, serious heart, liver and kidney disease.
Patients should not take orlistat if they are breastfeeding, suffering from pancreatitis or some types of gall bladder disease, or are normal or under weight.