Description

Hy's Law (used by Temple in reference to Hyman Zimmerman) can help to identify a drug with serious hepatotoxicity, ideally prior to regulatory approval.


 

Criteria for Hy's law:

(1) The patient is exposed to a drug that can cause hepatocellular injury (at rates in excess of any hepatotoxicity seen in controls).

(2) The total serum bilirubin is >= 2 times the upper limit of normal. Usually the patient is jaundiced but jaundice may be difficult to detect clinically.

(3) The serum transaminases (AST, ALT) are >= 3 times the upper limit of normal. The levels often are much higher.

(4) Exclusion of other explanations (cholestasis from intrahepatic or extrahepatic obstruction, Gilbert's syndrome, etc).

 

A patient who meets these criteria is at risk for serious hepatotoxicity with a 10-15% risk of death or liver transplant.

 

The underlying premise is that any hepatotoxic damage that is severe enough to interfere with bilirubin metabolism and excretion is significant.

 

Performance:

• The law can help to identify a drug that can be a serious threat. However, a drug may not meet the criteria and yet still be a significant hepatotoxin.

 


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