##  [First-Pass Effect](/first-pass-effect) 

  ##  [First-Pass Effect](https://health.quantumdictionary.io/first-pass-effect-0) 

  

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**Health & Life Sciences Dictionary**

 







 

 

 

 



 

 

 

 

Definition

A pharmacokinetic phenomenon in which a drug administered orally is substantially metabolized in the intestinal wall and/or liver before reaching systemic circulation, reducing its bioavailability compared with non‑portal routes (for example, intravenous administration).