Drug-induced Liver Injury: The Effect of Medication on Liver Function

Whether it is a common cold, fever, stomach upset, or just some bloating and acidity, we already have our medicine cabinets filled with drugs we can use for these routine ailments. While over-the-counter (OTC) medications like pain relievers and anti-allergic drugs are commonly sold and easily available, what is concerning is their excessive and inadvertent usage.

Often, prescription medications are taken without consulting doctors for a repeat infection or ailment with an old prescription. Did you know these habits can harm your body, especially the liver, which is the primary detoxification organ? In this article, we'll delve deeper into the effects of medication on liver function and explore ways to protect this vital organ. Let’s understand the relationship between medications and liver function, and ways to prevent drug-induced liver injury.

What are the causes of drug-induced liver injury

The liver is responsible for breaking down medicines and ensuring they are metabolised into the active form. The organ also plays a role in eliminating or removing any medicine by-products from the body. In some people, however, this drug metabolism process is slower, increasing the risk of liver damage from medication (called drug-induced liver damage).

Liver damage from medication can also occur when you consume an excessive amount of drugs or smaller amounts very frequently. Some medications cause hepatitis (liver inflammation) when consumed in small amounts, even if the liver function is normal. The most common medications that cause liver damage are painkillers and fever-reducing medications like acetaminophen (paracetamol) when taken in excess amounts or with alcohol.

Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, diclofenac and naproxen are another group of drugs well-known to cause liver damage. 

A few other drugs that may cause liver damage include:

• Erythromycin
• Isoniazid
• Tetracyclines
• Sulfa drugs
• Amoxicillin-clavulanates
• Methotrexate
• Statins (cholesterol-lowering medications)
• Methyldopa
• Birth control pills
• Some anti-seizure medications

Symptoms of drug-induced liver injury

The signs and symptoms of drug-induced liver injury are similar to other liver conditions and are characterised by the following:

• Dark urine
• Pale stools
• Abdominal pain
• Fever
• Fatigue
• Yellowing of the skin and white of the eyes
• Diarrhoea
• Nausea and vomiting
• Rash
• Headache

Medicinal herbs and liver injury

While a lot is known and said about how allopathic medications damage the liver, not many are aware that dietary supplements, including herbal products, can also have a similar effect on the liver. Many of these products are not regulated as OTC or prescription medications.

Pyrrolizidine alkaloids are one of the primary components found in hundreds of herbs and are known to damage the liver. Several herbs used in Chinese and Indian traditional medicine contain this compound.

When consumed in small quantities over a period of time, pyrrolizidine alkaloids damage the liver gradually by blocking the hepatic veins and preventing blood flow out of the liver. People affected by this condition complain of abdominal pain, nausea and vomiting. In these individuals, fluid accumulates in the abdomen and legs, eventually resulting in liver failure and might even result in death.

A few other herbs that may cause liver damage include:

• Camellia sinensis (used to make green and black teas)
• Green tea extract
• Germander
• Ephedra
• Mistletoe
• Pennyroyal oil

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

Liver injury due to medications does not occur in all individuals, but some factors can increase the likelihood of developing it. Generally, the risk of liver damage is thought to be increased due to the following factors:

• Obesity
• Pregnancy
• Consumption of alcohol in excess or frequently
• Genetic composition of the individual
• Congenital liver conditions
• Pre-existing liver diseases
• Presence of chronic diseases

Though not a drug, alcohol is a substance that is often abused and is notorious for causing liver damage. Consuming alcohol with drugs changes the way the liver metabolises drugs. It also reduces the body’s supply of antioxidants to protect the liver.

Treatment and prevention of drug-induced liver injuries

The good part about drug-induced liver injuries is that they get resolved a few days to weeks after the drug has been stopped or discontinued. This is also the first step in treating drug-induced liver conditions.

Treatment for drug-induced liver disease may also include the following steps:

• Administering an antidote (if available). An antidote is a drug that counters or neutralises the effect of another drug.
• Corticosteroids may be given in some cases.
• In severe cases of liver damage, a transplant may be needed.

In the case of excessive consumption of acetaminophen, liver injury may need to be treated in the emergency department.

Drug or medication-induced liver injury can be prevented. When drugs that are known to cause liver damage are used, doctors usually perform regular tests to monitor liver enzyme levels. This enables them to understand how the prescribed drug affects the liver and detect any problems or signs of liver damage early.

Conclusion

It is essential to consider the potential effects of medication on liver function. While medications can effectively treat various conditions, they can also have unintended consequences on the liver. It is crucial to discuss any concerns about medication and liver function with a healthcare provider, especially if you have a pre-existing liver condition or are taking multiple medications, to prevent drug-induced liver injury.

At the same time, making lifestyle changes like maintaining a healthy diet, staying hydrated, and avoiding alcohol and illicit drugs can help support liver function. By being mindful of the potential effects of medication on the liver and taking steps to support liver health, individuals can make informed decisions about their overall well-being.