Drug-Induced Liver Disease Causes, Symptoms, Diagnosis, and Treatment by MedicineNet.com

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Drug-Induced Liver Disease

Medical Author: Dennis Lee, MD
Medical Editor: Jay W. Marks, MD

What is drug-induced liver disease?

Drug-induced liver diseases are diseases of the liver that are caused by physician-prescribed medications, over-the-counter medications, vitamins, hormones, herbs, illicit ("recreational") drugs, and environmental toxins.

What is the liver?

The liver is an organ that is located in the upper right hand side of the abdomen, mostly behind the rib cage. The liver of an adult normally weighs close to three pounds and has many functions.

The liver produces and secretes bile into the intestine where the bile assists with the digestion of dietary fat.
The liver helps purify the blood by changing potentially harmful chemicals into harmless ones. The sources of these chemicals can be outside the body (for example, medications or alcohol), or inside the body (for example, ammonia, which is produced from the break-up of proteins; or bilirubin, which is produced from the break-up of hemoglobin).
The liver removes chemicals from the blood (usually changing them into harmless chemicals) and then either secretes them with the bile for elimination in the stool, or secretes them back into the blood where they then are removed by the kidneys and eliminated in the urine.
The liver produces many important substances, especially proteins that are necessary for good health. For example, it produces albumin, the protein building-block of the body, as well as the proteins that cause blood to clot properly.

Illustration of the Liver

When drugs injure the liver and disrupt its normal function, symptoms, signs, and abnormal blood tests of liver disease develop. Abnormalities of drug-induced liver diseases are similar to those of liver diseases caused by other agents such as viruses and immunologic diseases. For example, drug-induced hepatitis (inflammation of the liver cells) is similar to viral hepatitis; they both can cause elevations in blood levels of aspartate amino transferase (AST) and alanine aminotransferase (ALT) (enzymes that leak from the injured liver and into the blood) as well as anorexia (loss of appetite), fatigue, and nausea. Drug-induced cholestasis (interference with the flow of bile that is caused by injury to the bile ducts) can mimic the cholestasis of autoimmune liver disease (e.g., primary biliary cirrhosis or PBC) and can lead to elevations in blood levels of bilirubin (causing jaundice), alkaline phosphatase (an enzyme that is leaked from injured bile ducts), and itching.