Pharmacokinetics

Clearance CL

TRKlirens
Also known as:Drug clearance · total clearance

The rate at which a drug is removed from the body, primarily by the liver and kidneys, representing the volume of plasma cleared of the drug per unit time.

Formula

CL = Rate of elimination / Cp CL = F × Dose / AUC CL = CLR + CLH + CLother

In depth

Clearance is expressed as volume per unit time (e.g. L/h or mL/min) and is additive: total systemic clearance is the sum of renal (CLR), hepatic (CLH) and other organ clearances. It is constant under first-order kinetics and is estimated as F × Dose / AUC after a single dose, or as dosing rate divided by the average steady-state concentration.

Clearance is the main determinant of the average steady-state concentration for a given dosing rate and hence of the maintenance dose. Organ clearance depends on blood flow, the unbound fraction and the intrinsic eliminating capacity of the organ (enzymes, transporters, glomerular filtration).

Clinical pearl

Halving clearance doubles the steady-state concentration at an unchanged dose, which is why renal impairment or a potent enzyme inhibitor can make a previously well-tolerated dose toxic.

TRIn Turkish

Klirens

İlacın vücuttan (başta karaciğer ve böbrekler yoluyla) uzaklaştırılma hızı; birim zamanda ilaçtan arındırılan plazma hacmini temsil eder.

Klirens birim zamandaki hacim olarak (örneğin L/sa veya mL/dk) ifade edilir ve toplanabilir bir büyüklüktür: toplam sistemik klirens, renal (CLR), hepatik (CLH) ve diğer organ klirenslerinin toplamıdır. Birinci derece kinetikte sabittir; tek dozdan sonra F × Doz / AUC olarak, kararlı durumda ise doz hızının ortalama kararlı durum konsantrasyonuna bölünmesiyle hesaplanır.

Klirens, belirli bir doz hızında ortalama kararlı durum konsantrasyonunun ve dolayısıyla idame dozunun başlıca belirleyicisidir. Organ klirensi kan akımına, serbest fraksiyona ve organın intrinsik eliminasyon kapasitesine (enzimler, taşıyıcılar, glomerüler filtrasyon) bağlıdır.

Doz değiştirilmediğinde klirensin yarıya inmesi kararlı durum konsantrasyonunu iki katına çıkarır; bu nedenle böbrek yetmezliği veya güçlü bir enzim inhibitörü, daha önce iyi tolere edilen bir dozu toksik hâle getirebilir.

Diğer adları:İlaç klirensi · toplam klirens
Updated 24.09.2026 17 views Educational reference — verify against current sources before clinical use.

Read next

Renal ClearanceRenal Klirens

The component of total clearance attributable to the kidneys: the volume of plasma cleared of drug by urinary excretion per unit time.

 Hepatic ClearanceHepatik Klirens

The component of total clearance due to hepatic metabolism and biliary excretion; the volume of blood cleared of drug by the liver per unit time.

 Elimination Half-LifeEliminasyon Yarı Ömrü

The time required for the plasma concentration of a drug to decrease by 50% during the elimination phase, reflecting how long the drug remains active in the body.

 Steady-State ConcentrationKararlı Durum Konsantrasyonu

The constant plasma drug concentration achieved when the rate of drug administration equals the rate of elimination during repeated dosing.

 Maintenance Doseİdame Dozu

The dose given at regular intervals, or the rate of a continuous infusion, that replaces the amount of drug eliminated and keeps the concentration at the desired steady-state level.

 Area Under the CurveEğri Altındaki Alan

The integral of the plasma drug concentration–time curve, measuring total systemic exposure to a drug over a specified interval or from zero to infinity; expressed in concentration × time units (e.g. mg·h/L).