Drug therapy is dependent on pharmacokinetics and pharmacodynamics. Pharmacokinetics entails the study of drug assimilation, circulation, metabolism, and excretion. Clinical pharmacokinetics entails the use of pharmacokinetics principles in the safe administration of medicine in an individual patient. Pharmacodynamics is the analysis of biochemical and physiological ramification of drugs in the body.
Although the two disciplines are distinct, there is a relationship between pharmacokinetics and pharmacodynamics. The interplay between the dose given and the subsequent drug concentration at the site of action leads to a pharmacodynamic response. Therefore, pharmacodynamics illustrates the interplay between drug concentration and the desirable or undesirable clinical effects of medicine.
Pharmacokinetics establishes the concentration of medicine in the organism that is available to have the appropriate effect. A drug must enter the body and be absorbed into the organism’s blood to produce a positive or negative result. While in the blood, the medicine is distributed at a receptor and is subsequently taken to the liver, where it is metabolized into substances easily excreted in form of urine or feces.
It is noteworthy that medicines produce clinical effects by inhibiting or imitating biochemical processes. Therefore, drug efficacy is as a result of successful protein target, ion channel, or receptor interactions. Evidently, the link between the two disciplines becomes clear when examining the therapeutic efficacy, toxicity, and adverse reactions.