Question

With repeated i.v. doses of a drug, what happens to the concentration in the blood (plasma) and the t_1/2 if a patient’s kidneys were to fail?    Given a moderate i.v. dose and t1/2, how does dose interval influence the peak concentrations of drug in the blood? Under these circumstances, how might the drug become toxic to the patient.

***not a specific drug, just a general question

Answer 1

The concentration remains stable or consistent when the drug is given repeatedly or continuesly.This is known as steady state concentration.the time to reach steady state is a function of t1/2 and is achieved when the rate of drug entering the systemic circulation equals the rate of elimination. The human body has evolved multiple mechanism hepatic and renal that allow for elimination of drugs and other substances.As a result , immediately following the initial bolus dose,drug concentrations will begin to decline .. Slowing the rate of iv infusion allows distribution of drugs inthe body and drug elimination to take place ,and consequently lower peak plasma concentrations level occur.