Hy's law is a

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that a

patient A patient is any recipient of health care services that are performed by Health professional, healthcare professionals. The patient is most often Disease, ill or Major trauma, injured and in need of therapy, treatment by a physician, nurse, op ...

is at high risk of a fatal drug-induced liver injury if given a medication that causes hepatocellular injury (not Hepatobiliary injury) with

jaundice Jaundice, also known as icterus, is a yellowish or, less frequently, greenish pigmentation of the skin and sclera due to high bilirubin levels. Jaundice in adults is typically a sign indicating the presence of underlying diseases involving ...

. The law is based on observations by Hy Zimmerman, a major scholar of drug-induced liver injury.

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(CDER)

Center for Biologics Evaluation and Research The Center for Biologics Evaluation and Research (CBER) is one of six main centers for the U.S. Food and Drug Administration (FDA), which is a part of the U.S. Department of Health and Human Services. The current Director of CBER is Vinay Pras ...

(CBER)
Guidance for Industry Drug-Induced Liver Injury: Premarketing Clinical Evaluation, Final, July 2009
/ref> Some have suggested the principle be called a hypothesis or observation. Hy's Law cases have three components: * The drug causes hepatocellular injury, generally defined as an elevated ALT or AST by 3-fold or greater above the upper limit of normal. Often with aminotransferases much greater (5-10x) than the upper limit of normal. * Among subjects showing such aminotransferase elevations, they also have elevation of their serum total bilirubin of greater than 2× the upper limit of normal, without findings of cholestasis (defined as serum

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activity less than 2× the upper limit of normal). * No other reason can be found to explain the combination of increased aminotransferase and serum total bilirubin, such as viral hepatitis, alcohol abuse,

ischemia Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems ...

, preexisting liver disease, or another drug capable of causing the observed injury. In Zimmerman's analysis of 116 patients with hepatocellular injury and jaundice due to drug exposure, 76% went on to either require a liver transplant or died. Other studies have reported a lower but still significant mortality of 10%.

References

Diseases of liver Hepatology Rules of thumb {{treatment-stub