Basic Aspects and the Overview on Pharmacokinetics and Studies on Drug Distribution- A Panoramic Review

Patients who are in critical condition display a variety of organ dysfunctions and frequently need to be treated with a range of medications, such as sedatives, analgesics, neuromuscular blockers, antibiotics, inotropes, and gastric acid suppressants. A crucial component of treatment for this patient population is comprehending how organ dysfunction might change the pharmacokinetics of medications. Due to gastrointestinal failure, many medications will need to be administered intravenously. When the oral route is an option, hypomotility, changes in gut pH, and enteral feeding may affect bioavailability. The main factors affecting medication clearance, and consequently steady-state drug concentrations, efficacy, and toxicity in a given patient, are hepatic and renal dysfunction. Many medications are cleared from the body primarily through oxidative metabolism, and it is becoming increasingly understood how important it is for critically ill patients to have diminished hepatic cytochrome P450 system activity. Both filtration and secretion clearance pathways are necessary for the elimination of parent medications and their active metabolites, making renal failure equally crucial. Renal failure is frequently a secondary cause of changes in the steady-state volume of distribution, which can lower the body's effective medication concentrations. Failure of the endocrine, endothelium, muscular, or central neurological systems may also have an impact on how a medication is metabolized. For some medications, there is strong evidence that changes in pharmacokinetic characteristics depend on time. To maximize the pharmacodynamic response and result, it is essential to understand the underlying pathophysiology in the critically sick and utilize pharmacokinetic principles in the selection of drug and dosing regimen.