Drug-induced liver injury

What is a drug-induced liver injury?

Drug-induced liver injury (or hepatic drug reaction) is an injury to the liver that is caused by prescription medication, over-the-counter medication, vitamins and herbs, recreational drugs, and environmental toxins. 

What are the risk factors for drug-induced liver injury?

Risk factors for drug-induced liver injury include:

• Race: Some drugs appear to have different toxicities depending on race. 
• Age: Hepatic drug reaction is rare in children, however, elderly persons are at increased risk because of multiple hospitalisations and infections.
• Sex: Drug-induced liver injury is more common in women.
• Alcohol ingestion: People who are alcoholics are susceptible to drug toxicity because alcohol induces liver injury and alters drug metabolism.
• Pre-existing liver disease 
• Genetic factors
• Co-morbidities  

What are the symptoms of drug-induced liver disease?

The symptoms of liver disease include:

• fatigue, weakness
• abdominal pain
• jaundice (yellowing of the skin)
• itching
• water retention in the legs 
• kidney failure - in the more severe cases 

How do drugs cause liver disease?

Drug-induced liver disease can occur in different ways. Some drugs are transformed by the liver into chemicals that can cause either direct or indirect injury to the liver.

There are three types of liver toxicity:

• Dose-dependent toxicity: An example would be acetaminophen (Tylenol).
• Idiosyncratic toxicity: Can lead to liver disease in those with inherited specific genes that control the chemical transformation of the specific drug.
• Drug allergy: Although uncommon, the liver is injured by the inflammation that occurs when the body's immune system attacks the drug with antibodies. 

What types of liver disease do drugs cause?

Drug-induced liver disease can lead to the following:

• hepatitis
• necrosis
• cholestasis
• cirrhosis
• blood clots in the liver 

How is drug-induced liver injury treated?

The most important thing is to stop taking the drug that is causing the disease. In most cases, this enough to stop the symptoms and the liver disease will resolve, which will be monitored with blood tests.