Drug-induced Hepatitis

Authored by , Reviewed by Prof Cathy Jackson | Last edited | Meets Patient’s editorial guidelines

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Treatment of almost all medical conditions has been affected by the COVID-19 pandemic. NICE has issued rapid update guidelines in relation to many of these. This guidance is changing frequently. Please visit https://www.nice.org.uk/covid-19 to see if there is temporary guidance issued by NICE in relation to the management of this condition, which may vary from the information given below.

Drug-induced hepatitis involves inflammation of the liver, caused by medication. Drug-induced hepatitis is similar to acute viral hepatitis but parenchymal destruction tends to be more extensive. Certain drugs can cause damage to the liver in a variety of ways:

  • Acute hepatocellular damage:
    • Dose-unrelated - eg, antituberculous drugs, halothane, anticonvulsants.
    • Dose-related - eg, alcohol, paracetamol poisoning, amiodarone, methotrexate.
    • Both dose-unrelated and dose-related liver cell damage - eg, azathioprine.
  • Chronic active hepatitis - eg, isoniazid, nitrofurantoin.
  • Cirrhosis - eg, alcohol, methotrexate.
  • Hepatic tumours - eg, anabolic steroids, combined oral contraceptives.
  • Intrahepatic cholestasis: either dose-unrelated (eg, carbimazole, erythromycin, phenothiazines) or dose-related (eg, anabolic steroids, azathioprine, oestrogens).
  • Gallstones - eg, clofibrate, oestrogens.

Drug hepatoxicity can be non-idiosyncratic (predictable) or idiosyncratic (unpredictable). About 10% of cases are idiosyncratic.[1]

  • A very large number of drugs have been implicated as a potential cause of drug-induced hepatitis but with variable risk of both frequency and severity.
  • Estimates vary widely but 25-50% of all cases of hepatitis and even hepatic failure may be due to adverse drug effects.
  • Approximately 15% of patients with autoimmune hepatitis have drug-induced liver disease.[2]
  • The development of drug-induced liver disease is dependent on the drug as well as individual patient factors, including genetic predisposition, age, gender, pre-existing liver disease and comorbidities.[3]

There is no specific or diagnostic clinical presentation, laboratory test or histological pattern to aid in the diagnosis of drug-induced liver disease. Clinical features vary with the pattern and severity of injury, which vary with the particular drug and the individual patient.[4]

  • Often detected by routine drug monitoring - eg, disease-modifying antirheumatic drugs.
  • Symptoms and signs are similar to other causes of liver damage. Thus, identifying drug-induced hepatitis relies on the history of exposure more than any particular finding on examination or investigation.
  • Clinical evidence of sensitivity to a medication may occur on the first day of its use or not until several months later, depending on the medication.
  • Usually, the onset is abrupt, with chills, fever, rash, pruritus, arthralgia, headache, abdominal pain, anorexia, nausea and vomiting.
  • Later, overt evidence of liver damage, such as jaundice, dark urine and an enlarged and tender liver, may develop.
  • Two general pathogenic mechanisms are recognised:
    • Predictable or direct: usually promptly follows an exposure to a new medication. The mechanism appears to be due to direct toxicity or a toxic metabolite - eg, paracetamol.
    • Unpredictable or idiosyncratic: may be related to immune hypersensitivity; rash, fever and eosinophilia are typically present. These reactions follow exposure by a few weeks - eg, Augmentin®.
  • Late-onset idiosyncratic reactions are difficult to recognise. They follow exposure by many months and usually do not display features of hypersensitivity - eg, isoniazid.

Medication-induced liver injury typically presents in one of three clinical patterns:

  • Hepatitis: elevated AST/ALT - eg, paracetamol poisoning, thiazolidinediones, statins.
  • Cholestasis: elevated alkaline phosphatase - eg, chlorpromazine, erythromycin, oestrogens.
  • Mixed picture with damage to both biliary canaliculi and hepatocytes: variable elevations in aminotransferases and alkaline phosphatase - eg Augmentin®.
  • Investigations may also need to include an assessment for other causes of hepatitis and may include hepatitis viral serology, antinuclear antibodies, copper and iron levels, abdominal ultrasound, CT/MRI scan and liver biopsy.
  • There is no specific treatment for drug-induced hepatitis other than discontinuing the medication that is causing the problem.
  • People with acute hepatitis should avoid physical exertion, alcohol, paracetamol and any other hepatotoxic substances.
  • Unfortunately, other than the use of N-acetylcysteine for paracetamol hepatotoxicity, there are no specific antidotes for drug-induced liver disease.
  • Supportive care for acute liver failure and even liver transplantation may be required.

Liver failure is a possible but uncommon complication of drug-induced hepatitis. The risk of acute liver failure is dependent on the degree of abnormality of liver enzyme levels and the presence of pre-existing liver disease. The risk is higher in women.[6, 7]

  • Usually symptoms subside when the causative drug has been discontinued and drug-related hepatitis subsides within days or weeks after the offending drug is stopped.
  • Reactions may be severe and even fatal.
  • Careful prescribing and, when recommended, monitoring of all medication in line with established guidelines.
  • Always consider drugs as a cause of any patient presenting with hepatitis in order to provide early effective management.

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Further reading and references

  1. Leise MD, Poterucha JJ, Talwalkar JA; Drug-induced liver injury. Mayo Clin Proc. 2014 Jan89(1):95-106. doi: 10.1016/j.mayocp.2013.09.016.

  2. Yeong TT, Lim KH, Goubet S, et al; Natural history and outcomes in drug-induced autoimmune hepatitis. Hepatol Res. 2015 May 5. doi: 10.1111/hepr.12532.

  3. Clinical guidelines for immunoglobulin use; Dept of Health, July 2011

  4. Fisher K, Vuppalanchi R, Saxena R; Drug-Induced Liver Injury. Arch Pathol Lab Med. 2015 Jul139(7):876-87. doi: 10.5858/arpa.2014-0214-RA.

  5. Weiler S, Merz M, Kullak-Ublick GA; Drug-induced liver injury: the dawn of biomarkers? F1000Prime Rep. 2015 Mar 37:34. doi: 10.12703/P7-34. eCollection 2015.

  6. Lo Re V 3rd, Haynes K, Forde KA, et al; Risk of Acute Liver Failure in Patients with Drug-Induced Liver Injury: Evaluation of Hy's Law and a New Prognostic Model. Clin Gastroenterol Hepatol. 2015 Jun 26. pii: S1542-3565(15)00844-7. doi: 10.1016/j.cgh.2015.06.020.

  7. Robles-Diaz M, Lucena MI, Kaplowitz N, et al; Use of Hy's law and a new composite algorithm to predict acute liver failure in patients with drug-induced liver injury. Gastroenterology. 2014 Jul147(1):109-118.e5. doi: 10.1053/j.gastro.2014.03.050. Epub 2014 Apr 1.