Drug-Induced Liver Injury: What You Need to Understand !! -

Introduction

Drug-induced liver injury is one of the important causes of liver damage. Many prescription medicines, over-the-counter drugs, and herbal products are known to have the potential to harm the liver. In some cases, drug-related liver damage can be severe and may lead to Acute liver failure, requiring a liver transplant or even becoming life-threatening. Fortunately, such serious reactions are rare, but it is important to use medicines responsibly and under medical guidance. Early recognition of drug-induced liver damage is important. Stopping the medicine promptly can help prevent more serious complications.

Understanding Drug-Induced Liver Injury

Drug-induced liver injury is liver or biliary system damage caused by medicines, herbal products, or dietary supplements.
The risk and pattern of liver damage may vary geographically, depending on local disease patterns, treatment practices, and commonly used medicines or traditional remedies.

Types of Drug-Induced Liver Injury

Idiosyncratic

Occurs in very few people: about 1 in 1,000 to 1 in 1 million exposed individuals.
Usually unpredictable and not clearly dose-dependent.
Symptoms may develop weeks to months later, depending on the drug and mechanism.

Direct (Intrinsic)

Predictable and dose-dependent.
Can affect many exposed individuals when a threshold dose or duration of exposure is exceeded.
Symptoms usually appear within hours to days.
Severity generally depends on the dose taken.

Indirect

A medicine may not damage the liver directly but can cause liver injury indirectly.
for example by changing the immune response or reactivating a hidden infection such as hepatitis B.
Generally not dose-dependent, similar to idiosyncratic.
Usually develops after a week to a month.

Risk Factors

Certain patient, lifestyle, and drug-related factors may increase the risk:
- Age: Children and older adults may be more susceptible.
- Gender: Some forms may occur more frequently or be more severe in women.
- Health conditions: Hepatitis B or C, obesity, diabetes, and fatty liver disease may increase risk.
- Alcohol: Heavy alcohol use can increase the risk of liver damage.
- Nutrition: Malnutrition or overnutrition may contribute.
- Multiple medicines: Drug interactions can increase risk.
- Genetics: Certain genetic factors may increase susceptibility.
- Gut microbiota: Changes in gut bacteria may also influence liver damage.

Classic example of direct liver injury

Paracetamol (acetaminophen) is a common medicine used for pain and fever.
It is a classic example of a medicine that can cause liver damage when taken in excessive doses.
Paracetamol overdose may be accidental or intentional.
Severe overdose can lead to acute liver failure and, in some cases, the need for a liver transplant.
Many combination medicines also contain paracetamol, increasing the risk of accidental overdose.
Always check medicine labels before taking more than one product containing paracetamol.

Learn More: 💊 Your Trusted Paracetamol: Essential Facts You Need to Know — Read our blog

Common causes of idiosyncratic Liver Injury in India

The idiosyncratic form constitutes ~99% of all liver damage cases in India. The common causes are as listed below.

Anti-Tuberculosis Drugs

Anti-Tuberculosis Drugs are the Leading cause of drug-induced liver damage and acute liver failure in India.
Usually occurs within the first 2 months of treatment.
The widespread use of combination anti-tuberculosis therapy, particularly isoniazid, rifampicin, and pyrazinamide, increases the risk of liver toxicity
Drug interactions, high doses, malnutrition, and Genetic factors may contribute.

Note: In India, acute hepatitis E should be ruled out before diagnosing drug-induced liver injury, as it can cause similar liver abnormalities.

Traditional and Complementary Medicines

Ayurveda, Unani, Siddha, and Homeopathy are widely used in India—and sometimes taken alongside modern medicines.
But “natural” or traditional does not always mean risk-free. Some preparations may contain undisclosed ingredients, contaminants, or heavy metals that can potentially harm the liver.

Antiepileptic Drugs

Older antiepileptics such as phenytoin, carbamazepine, and phenobarbitone can cause liver damage.
However, with the greater use of newer drugs with a better liver safety profile, the incidence of liver damage is decreasing.

Non-Tuberculosis Antimicrobials

Non-Tuberculosis antimicrobials constitute the fourth-largest cause of liver damage.
The top three drugs in this group are:

Causes of Indirect Liver Injury

Indirect liver injury can occur with some cancer medicines, including immunotherapies, monoclonal antibodies, and targeted therapies.
Examples
- Cancer immunotherapy: ipilimumab, nivolumab, pembrolizumab
- Monoclonal antibody Therapy: rituximab
- Targeted cancer medicines: imatinib, lapatinib, regorafenib

Recognizing Drug-Induced Liver Injury

Liver damage due to drugs often causes no symptoms. If symptoms occur, they can vary from person to person and may include:
- Yellow eyes or skin (jaundice)
- Tiredness or weakness
- Stomach pain
- Nausea or Vomiting
- Dark urine
- Itchy skin
In severe cases, it can lead to liver failure.

Diagnosis of Drug induced liver injury

There is no single test. Doctors usually diagnose it by:
- Reviewing medicines: Checking which medicines or supplements the person is taking.
- Blood tests: Liver enzymes, bilirubin, international normalized ratio, and complete blood count may be checked.
- Ruling out other causes: Tests may be done for viral hepatitis and autoimmune liver disease.
- Imaging: Ultrasound or MRI may be used to check for other problems.
- Liver biopsy: Usually not needed, but may help when the diagnosis is unclear.

Managing Drug-Induced Liver Injury

Do not restart the suspected medicine unless advised by a healthcare professional.
Maintain adequate fluids, nutrition, and electrolyte balance.
Regularly check liver function tests to track recovery.
Avoid alcohol.
Eat a balanced diet.
Get adequate rest.
Avoid self-medication and medicines or supplements that may further harm the liver.

Key Takeaways

Drug-induced liver injury can be caused by prescription medicines, over-the-counter drugs, herbal products, and dietary supplements.

Anti-tuberculosis drugs are a leading cause of drug-induced liver injury in India.

Natural or traditional products are not always liver-safe.

Paracetamol overdose is a classic example of predictable, dose-related liver injury.

Drug-induced liver injury often causes no symptoms.

Severe cases can lead to acute liver failure, although this is uncommon.

Early recognition and appropriate medical management are important.

Do not self-medicate or restart a suspected medicine without medical advice.

Drug-Induced Liver Injury: What You Need to Understand !!

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