Basic concepts of clinical pharmacokinetics.
Clinical pharmacology is now a well established discipline. Unlike the yester years when dosage schedules were determined by trial and error, in the present day selection of dose, dosage interval and route of administration are based on pharmacokinetic and pharmacodynamic principles. The primary utility of pharmacokinetics is to study the process of absorption, distribution, metabolism and elimination of drugs, fundamental for drug action. Individuals show a wide variation in kinetic parameters due to internal and external factors. Sometimes change in one variable may be compensated by change in another variable so that dose need not be altered e.g. metabolism of some drugs is increased in thyrotoxicosis but due to increased protein binding overall dose adjustment may not be required. On the other hand sometimes variations in these parameters can markedly affect the plasma concentrations of and the pharmacological response to drugs e.g. anticonvulsant treatment in oral contraceptive users, phenylbutazone addition in warfarin therapy. Drug concentrations can be measured in plasma, urine or saliva. Equipped with this knowledge the modern physician will be able to make a wiser use of drugs under altered physiological conditions like pregnancy, lactation, infancy, old age and pathological states like renal and liver failure and shock.
Raghuram
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TC
National Institute of Nutrition, Jamia-osmania, Hyderabad.
Krishnaswamy
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K
D000042:Absorption; D001798:Blood Proteins / Q000378:metabolism; D004333:Drug Administration Routes; D006801:Humans; D008657:Metabolic Clearance Rate; D008954:Models, Biological; D010599:Pharmacokinetics; D011485:Protein Binding
D001798:Blood Proteins