Question

Understand the pharmacokinetic processes and how they can be affected by route of drug administration, patient size, and organ health.

Answer 1

Answer-Pharmacokinetics refers to what happens to a medication from entrance into the body untill the exit of all traces.Four processes encompass the pharmacokinetics of a medication.The main process involved in pharmacokintics are Absorption, Distribution,and the two routes of drug elimination, Metabolism and Excretion.Together they are sometimes known by the acronym "ADME".Each of these process is influenced by the route of administration nd functioning of body organs.The pharmacokinetic parameters are assessed by monitoring varitions in concentration of the drug and/ or its metabolites in physiological fluids that are easy to access(i.e,plasma and urine)Plasma concentrations are usually checked,and in addition biopsies can be taken from animals and sometimes from humans.Absorption refers to the movement of a medication from where it entered the body to the bloodstream.After absorption comes distribution or transport of the medication via the bloodstream to the intended action site.The blood supply to the area will determine the rate of distribution.Metabolism refers to the breakdown of medication into an inactive form. Metabolism is also reffered to as biotransformation because of the effect onthe chemical consistency of medication..The main organs responsible for drug excreation are the kidneys(renal excreation) and the liver (biliary excreation).Other organs can be involved in excreation,such as the lungs for volatile or gaseous agents.Drugs can also partially be excreated in to sweat,saliva and tears.

The main routes of drug administration such as entral,  parentral, ( subcutaneous,intramuscular,intravenous intratacheal)mucous membrane ,and transdermal are chosen to take advantage of transport and other mechanisms that permit the drug to enter the body.A drug's rate of absorption is greatly influenced by FIRST-PASS METABOLISM ,a process by which liver enzymes inactivate a fraction of the drug.Changes in body composition,hepatic and renal function are responsible for an increase in the volume of distribution of lipid soluble drugs. Important pharmacokinetic changes occur with advancing age.Therate of drug metabolism and excreation by an organ is limited by the rate of blood flow to that organ.