What is clearance pharmacokinetics?

In pharmacology, clearance is a pharmacokinetic measurement of the volume of plasma from which a substance is completely removed per unit time. Usually, clearance is measured in L/h or mL/min.

What does decreased plasma clearance indicate?

Clearance (Cl) When the value for clearance is high, it suggests that the xenobiotic is removed rapidly from the body, whereas a low clearance value indicates slower removal. Therefore, Cl may be regarded as the apparent volume of blood from which the xenobiotic is removed during a given period of time.

What is meant by drug clearance?

Drug clearance is defined as the volume of plasma cleared of a drug over a specified time period. [1] Thus, the units of measurement for drug clearance is in is volume/time. Another equation can calculate clearance.

How is plasma clearance calculated?

The total clearance of all of the elimination processes in the body is calculated by dividing the dose administered by the total area under the Cp time curve (AUC) from the time of dosing until drug concentrations can no longer be measured (CL = Dose/AUC).

What’s the difference between elimination and clearance?

Clearance is defined as ‘the volume of blood cleared of drug per unit time’. Drug elimination rate is defined as ‘the amount of drug cleared from the blood per unit time’ In first order kinetics, elimination rate is proportional to dose, while clearance rate remains independent of the dose.

What organs are most important in total body clearance?

Drug clearance by metabolism and elimination is essential in PK and dictates maintenance dosing concentrations and frequency. The liver and the kidneys are responsible for metabolism and elimination, respectively; blood flow and uptake in these organs dictate the extent of clearance.

What is hepatic clearance?

Hepatic clearance, or the ability of the liver to extract and metabolize a drug as it passes through the liver, is controlled by hepatic blood flow (Q), protein binding (fu) and the intrinsic ability of the liver enzymes to metabolize a drug (Clint).

What are the advantages of expressing clearance at an individual organ level?

An understanding of organ clearance concepts, linked to basic principles of clinical pharmacokinetics and therapeutic drug monitoring, will facilitate interpretation of blood drug concentrations in individual patients and consequently help individualize drug dosages to achieve steady-state concentrations within a range …

Which organ is associated with drug clearance?

Although many sites of metabolism and excretion exist, the chief organ of metabolism is the liver, while the organ primarily tasked with excretion is the kidney. Any significant dysfunction in either organ can result in the accumulation of the drug or its metabolites in toxic concentrations.

How can I reduce my drug clearance?

Drug clearance could be reduced either by increasing the drug’s stability toward metabolizing enzymes and/or by modifying its hepatic disposition profile, ie, by decreasing drug concentrations in liver cells.

What is plasma clearance rate?

Plasma clearance (a volume per time, i.e. a flow) expresses the overall ability of the body to eliminate a drug by scaling the drug elimination rate (amount per time) by the corresponding plasma concentration level.

Which substance has lowest plasma clearance?

Inulin
Inulin has unique properties that make it the only substance whose clearance is exactly equal to the glomerular filtration rate (GFR). Inulin is freely filtered across the glomerular capillaries, but once filtered, it is neither reabsorbed nor secreted.

Which is the best symbol for plasma clearance?

HVolume/time or volume/time/kg Hepatic clearance of the drug from plasma CL intVolume/time or volume/time/kg Intrinsic clearance of drug from plasma by the liver devoid of influence of blood flow or protein binding CL mVolume/time or volume/time/kg Apparent total body clearance of metabolite from the plasma CL

What is the definition of clearance in pharmacology?

Clearance (pharmacology) In pharmacology, the clearance is a pharmacokinetic measurement of the volume of plasma from which a substance is completely removed per unit time; the usual units are mL/min.

Which is the best symbol for drug clearance?

intVolume/time or volume/time/kg Intrinsic clearance of drug from plasma by the liver devoid of influence of blood flow or protein binding CL mVolume/time or volume/time/kg Apparent total body clearance of metabolite from the plasma CL NRVolume/time or volume/time/kg Nonrenal clearance of the drug from plasma CL

What is the coefficient of proportionality of drug clearance?

Clearance is precisely this coefficient of proportionality. By contrast, the fraction of drug that is eliminated remains constant. Clearance of most drugs, for which excretion and metabolism are not saturated, is constant over the range of doses encountered clinically. Such drugs are said to undergo first order kinetics.