Pharmacokinetics

Enterohepatic Recirculation

TREnterohepatik Dolaşım
Also known as:Enterohepatic circulation · Enterohepatic cycling

The cycle in which a drug or its conjugated metabolite is excreted in bile into the intestine, reabsorbed (after deconjugation, if conjugated) and returned to the liver via the portal circulation.

In depth

Glucuronide and other conjugates excreted in bile are hydrolysed in the gut by bacterial enzymes such as β-glucuronidase, releasing the parent drug for reabsorption. The cycle prolongs the apparent half-life and mean residence time and can produce secondary peaks in the plasma concentration–time profile.

Drugs with clinically relevant enterohepatic recirculation include mycophenolic acid, ethinylestradiol and some NSAIDs such as indometacin. The cycle can be interrupted by bile-acid sequestrants such as colestyramine and by multiple-dose activated charcoal.

Clinical pearl

Bile-acid sequestrants such as colestyramine interrupt enterohepatic recirculation and can substantially reduce exposure to recirculating drugs such as mycophenolic acid; the same principle underlies multiple-dose activated charcoal in some poisonings.

Example drugs

Mycophenolic acid Ethinylestradiol indometacin
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Enterohepatik Dolaşım

Bir ilacın veya konjuge metabolitinin safrayla bağırsağa atıldığı, burada (konjugat ise dekonjugasyondan sonra) yeniden emildiği ve portal dolaşımla karaciğere geri döndüğü döngüdür.

Safrayla atılan glukuronit ve diğer konjugatlar bağırsakta β-glukuronidaz gibi bakteriyel enzimlerce hidrolize edilir ve serbestleşen ana ilaç yeniden emilir. Bu döngü görünür yarılanma ömrünü ve ortalama kalış süresini uzatır, plazma konsantrasyonu–zaman profilinde ikincil doruklar oluşturabilir.

Klinik açıdan önemli enterohepatik dolaşım gösteren ilaçlar arasında mikofenolik asit, etinilestradiol ve indometasin gibi bazı NSAİİ'ler bulunur. Döngü, kolestiramin gibi safra asidi bağlayıcı reçinelerle ve çoklu doz aktif kömürle kesilebilir.

Kolestiramin gibi safra asidi bağlayıcıları enterohepatik dolaşımı keserek mikofenolik asit gibi döngüye giren ilaçlara maruziyeti önemli ölçüde azaltabilir; bazı zehirlenmelerde çoklu doz aktif kömür kullanımı da aynı ilkeye dayanır.

Diğer adları:Enterohepatik resirkülasyon · Enterohepatik siklus
Updated 24.09.2026 1 views Educational reference — verify against current sources before clinical use.

Read next

ExcretionAtılım (Ekskresyon)

The removal of unchanged drug or its metabolites from the body, principally in urine and in bile (faeces), and to a lesser extent in exhaled air, sweat, saliva and breast milk.

 GlucuronidationGlukuronidasyon

A phase II conjugation reaction in which UDP-glucuronosyltransferases (UGTs) transfer glucuronic acid from UDP-glucuronic acid to a hydroxyl, carboxyl, amine or thiol group on a drug or metabolite.

 Activated CharcoalAktif Kömür

A highly porous, finely powdered carbon adsorbent given orally or by nasogastric tube that binds many drugs and toxins in the gut lumen, limiting their systemic absorption and, with repeated doses, enhancing the elimination of some.

 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.

 Enhanced EliminationEliminasyonun Hızlandırılması

Measures that increase the removal of an already absorbed drug or toxin from the body beyond its intrinsic clearance, used in selected poisonings to shorten exposure and reduce toxicity.