Changes

==Metabolism==

==Metabolism==

For drugs to be eliminated from the body in a more water soluble form, most drugs require metabolism. The extent of metabolism varies between species and age. Herbivores metabolise drugs the most efficiently followed by dogs and then cats. This is due to the amount of metabolising enzymes present differ in each species. Old and neonatal animals show reduced hepatic metabolisma and renal excretion. Neonates also have greater absorption via the gastrointestinal tract and have an increased permeability of the blood brain barrier. This means that a neonate has higher plasma levels of a drug than an adult and so are at greater risk to drug toxicity.  

For drugs to be eliminated from the body in a more water soluble form, most drugs require metabolism. The extent of metabolism varies between species and age. Herbivores metabolise drugs the most efficiently followed by dogs and then cats. This is due to the amount of metabolising enzymes present differ in each species. Old and neonatal animals show reduced hepatic metabolism and renal excretion. Neonates also have greater absorption via the gastrointestinal tract and have an increased permeability of the blood brain barrier. This means that a neonate has higher plasma levels of a drug than an adult and so are at greater risk to drug toxicity.  

In certain drugs the metabolite is in fact the active form. The adminstered inactive form is called a '''pro-drug'''.

In certain drugs the metabolite is in fact the active form. The adminstered inactive form is called a '''pro-drug'''.