Pharmacokinetics

Hepatic Clearance CLH

TRHepatik 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.

Formula

CLH = QH × EH CLH = QH × fu × CLint / (QH + fu × CLint)

In depth

Hepatic clearance equals hepatic blood flow (QH, roughly 1.5 L/min in adults) multiplied by the hepatic extraction ratio (EH). The well-stirred model relates it to QH, the unbound fraction in blood (fu) and intrinsic clearance (CLint), the inherent capacity of hepatic enzymes and transporters.

For low-extraction drugs, CLH ≈ fu × CLint: clearance is capacity-limited and sensitive to enzyme induction or inhibition and to protein binding, but not to blood flow. For high-extraction drugs, CLH ≈ QH: clearance is flow-limited and changes with cardiac output and hepatic blood flow.

Clinical pearl

Liver disease reduces hepatic clearance unpredictably and, unlike renal impairment, has no simple laboratory marker to guide dosing; product information commonly uses the Child–Pugh class as a rough guide.

Example drugs

Warfarin Theophylline Lidocaine Propranolol
TRIn Turkish

Hepatik Klirens

Toplam klirensin hepatik metabolizma ve safra ile atılıma bağlı bileşenidir; birim zamanda karaciğer tarafından ilaçtan arındırılan kan hacmidir.

Hepatik klirens, karaciğer kan akımı (QH; erişkinde yaklaşık 1,5 L/dk) ile hepatik ekstraksiyon oranının (EH) çarpımına eşittir. İyi karıştırılmış (well-stirred) model hepatik klirensi QH, kandaki serbest fraksiyon (fu) ve karaciğer enzim ve taşıyıcılarının doğal kapasitesini gösteren intrinsik klirensle (CLint) ilişkilendirir.

Ekstraksiyonu düşük ilaçlarda CLH ≈ fu × CLint'tir: klirens kapasiteyle sınırlıdır; enzim indüksiyonu veya inhibisyonuna ve protein bağlanmasına duyarlı, kan akımına ise duyarsızdır. Ekstraksiyonu yüksek ilaçlarda CLH ≈ QH'dir: klirens akımla sınırlıdır ve kalp debisi ile karaciğer kan akımına bağlı olarak değişir.

Karaciğer hastalığı hepatik klirensi öngörülemez biçimde azaltır ve böbrek yetmezliğinin aksine doz ayarlamasına yol gösteren basit bir laboratuvar belirteci yoktur; ürün bilgilerinde kaba bir ölçüt olarak çoğunlukla Child–Pugh sınıfı kullanılır.

Diğer adları:Karaciğer klirensi
Updated 24.09.2026 0 views Educational reference — verify against current sources before clinical use.

Read next

Hepatic Extraction RatioHepatik Ekstraksiyon Oranı

The fraction of drug entering the liver in the blood that is irreversibly removed during a single pass through the organ, ranging from 0 (no extraction) to 1 (complete extraction).

 ClearanceKlirens

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.

 Cytochrome P450Sitokrom P450

A superfamily of heme-containing monooxygenase enzymes, located mainly in the endoplasmic reticulum of hepatocytes and enterocytes, that catalyze most phase I oxidative drug metabolism.

 Enzyme InductionEnzim İndüksiyonu

An increase in the amount and activity of a drug-metabolizing enzyme or transporter, usually through enhanced gene transcription, caused by repeated exposure to a drug or other xenobiotic.

 Child–Pugh ScoreChild–Pugh Skoru

A clinical scoring system that grades the severity of chronic liver disease, mainly cirrhosis, from five variables into classes A, B and C.

 First-Pass Effectİlk Geçiş Etkisi

The metabolism of a drug in the liver (or gut wall) before it reaches systemic circulation, often reducing the bioavailability of orally administered drugs.