Calculation of Dialysis Clearance

2018 Dialysis Drugs

Currently, the efficiency of hemodialysis is expressed in terms of dialysis clearance. Dialysis clearance (CLd) is usually estimated from the Fick equation as follows where A is the solute concentration entering (arterial) and V is the solute concentration leaving (venous) the dialyzer. The terms in brackets collectively describe what is termed the extraction ratio (E). As a general principle, clearance from an eliminating organ can be thought of as the product of organ blood flow and...

Effects Of Renal Disease On Drug Distribution

Impaired renal function is associated with important changes in the binding of some drugs to plasma proteins. In some cases the tissue binding of drugs is also affected. albumin binding sites by organic molecules that accumulate in uremia. As described in Chapter 3, reductions in the protein binding of acidic drugs result in increases in their distribution volume. In addition, the elimination clearance of restrictively eliminated drugs is increased. However, protein binding changes do not...

Therapeutic Response Cumulative Drug Effects And Schedule Dependence

Lasix Pharmacokinetics

So far we have focused our attention on the time course of drug effect. While the study of these effects can be helpful in understanding the mechanism of drug action and factors affecting efficacy and potency, it usually does not provide information on how drug exposure influences therapeutic response. Clinical response can be defined as the effect of drug treatment on the clinical endpoint of how the patient feels, functions, or survives. Some clinical responses can be described by composite...

Effects of Liver Disease on the Renal Elimination of Drugs

Threpyomycin

Drug therapy in patients with advanced cirrhosis is further complicated by the fact that renal blood flow and glomerular filtration rate are frequently depressed in these patients in the absence of other known causes of renal failure. This condition, termed the hepatorenal syndrome, occurs in a setting of vasodilation of the splanchnic circulation that results in underfilling of the systemic circulation. This activates pressor responses, causing marked vasoconstriction of the renal circulation...