Toxic or Drug-Induced Hepatitis
The liver is responsible for the metabolism of alcohol, drugs, and every other chemical to which a person is exposed, breaking them down into substances that can be used and/or eliminated from the body. This process rarely produces byproducts that can harm the liver, resulting in hepatitis. Symptoms of toxic hepatitis often appear quickly, within hours or days of exposure to a substance, while with drug-induced hepatitis, they develop slowly after repeated use of alcohol, a drug, or exposure to a chemical.
Examples of substances that are directly toxic (or have byproducts made in the liver that are directly toxic) to the liver include industrial solvents, cleaning solvents, pollutants and some drugs. Acetaminophen, which is found in numerous over-the-counter and prescription medications, is an example of a drug that can cause toxic hepatitis. In therapeutic doses, acetaminophen is a useful pain reliever, but in very high doses or in combination with alcohol, it has the potential to cause life-threatening acute liver failure.
Examples of commonly used products that are capable of causing drug-induced hepatitis include:
- Aspirin, ibuprofen, and naproxen sodium (especially if combined with alcohol)
- Herbal supplements, including cascara, chaparral, comfrey, kava and ephedra
- Large doses of vitamin supplements
Excessive consumption of alcohol is a common cause of drug-induced hepatitis. The liver inflammation may be chronic yet mild, lasting for years with no specific symptoms. However, over time, the liver may sustain more and more damage. The rate of mortality in severe cases of alcohol-induced hepatitis (also called alcoholic steatohepatitis) is about 50%. The damage may be reversed if alcohol consumption is stopped.
Many prescription drugs have the potential to cause drug-induced hepatitis. Their effect on the liver cannot be foreseen and appears to be related to an immune reaction to the medication. The list of prescription drugs that can damage the liver is long and continues to grow. Among them are certain anesthetics, antibiotic and antifungal medications, anabolic steroids, drugs used to lower cholesterol, chemotherapy drugs, and seizure medications.
Signs and symptoms of toxic and drug-induced hepatitis vary depending on the cause. They may appear suddenly or develop gradually with prolonged exposure to a drug or other toxin. When present, signs and symptoms often correspond to those of hepatitis in general. See the section on Signs and Symptoms for detailed information.
The diagnosis of toxic and drug-induced hepatitis is often arrived at for a patient with hepatitis by obtaining a full medical history that focuses on the use of over-the-counter and prescription medications, herbs, and vitamin supplements; alcohol use; and, where applicable, evaluating hazards the patient may have been exposed to in the workplace, such as industrial solvents. Tests that may be performed to help evaluate patients with toxic hepatitis include the following:
- Liver panel – to evaluate liver function and/or determine the extent of liver damage
- Ethanol level – if alcohol is suspected to be a cause
- Emergency and overdose drug testing – including tests for drugs of abuse, acetaminophen, and therapeutic drugs to help determine the cause of hepatitis and guide treatment
- Liver biopsy – to determine the type and extent of liver damage
There is no specific treatment for most kinds of toxic or drug-induced hepatitis. Usually, discontinuing use of alcohol or the medication that is causing the liver damage or avoiding exposure to toxins is the first step. Many people fully recover from this type of hepatitis if exposure is restricted soon enough, although it may take months for the liver to heal. In severe cases, hospitalization may be required while the liver heals. Occasionally, there is lasting damage, such as cirrhosis and even liver failure. If the liver is irreversibly damaged, then a liver transplant may be an option.
There is treatment available for an overdose of acetaminophen that can minimize damage to the liver. N-acetylcysteine (NAC) may be given as an antidote within 24 hours of ingestion. It is most effective as an antidote if given within 8 hours of ingestion, so it is important to identify and treat this condition as soon as possible.