What is hy s law?

Hy's law, also known as Hy's Rule or the Rule of Two, is a medical principle that helps predict the likelihood of drug-induced liver injury (DILI) in patients taking medications. It states that if a patient experiences elevated liver enzymes (specifically, alanine transaminase and/or aspartate transaminase) greater than two times the upper limit of normal and concurrent total bilirubin greater than two times the upper limit of normal, while taking a medication, then that medication is likely the cause of the liver injury.

This law was first proposed by Dr. Hyman Zimmerman in 1961 and has since been widely used in clinical practice, drug development, and regulatory agencies. It is especially useful in identifying severe forms of DILI, such as drug-induced liver failure, which can be fatal if not detected and treated early.

However, it is important to note that Hy's law has limitations and may not apply to all patients or medications. Other factors, such as patient age, gender, underlying liver disease, and genetic factors, can also influence the development of DILI. Therefore, it is essential for healthcare providers to carefully monitor patients taking medications that have the potential to cause DILI and to promptly investigate any signs of liver injury.