Absorption, Distribution, Metabolism and Excretion.


Are done to assess the amount of chemical or pharmaceutical that is absorbed into the animal, where it is distributed within the body, how it is changed by metabolism, the time-course for these events and how, and at what rate, the material is eliminated from the body.

A - Absorption:

Before a compound can exert a pharmacological effect in bloodstream / tissues. Absorption critically determines the compound's bio-availability.

D - Distribution:

The compound needs to be carried to its effector site, most often via the bloodstream. From there, the compound may distribute into tissues and organs, usually to differing extents.

M - Metabolism:

Compounds begin to be break down as soon as they enter the body. The majority of small-molecule drug metabolism is carried out in the liver by redox enzymes, termed cytochrome P450 enzymes. As metabolism occurs, the initial (parent) compound is converted to new compounds called metabolites. When metabolites are pharmacologically inert, metabolism deactivates the administered dose of parent drug and this usually reduces the effects on the body. Metabolites may also be pharmacologically active, sometimes more so than the parent drug.

E - Excretion:

Compounds and their metabolites need to be removed from the body via excretion, usually through the kidneys (urine) or in the feces. Unless excretion is complete, accumulation of foreign substances can adversely affect normal metabolism.