Liver damage due to medication

Paracetamol is certainly the best-known example of a drug that damages the liver when overdosed, but it is by no means the only one. Many medicines do not require too high a dose to attack the liver. The German Society for Digestive and Metabolic Diseases (DGVS) warns that liver damage caused by medication is an underestimated side effect. Around one in ten side effects relates to the liver. Apart from paracetamol, it is often non-steroidal anti-inflammatory drugs (NSAIDs) and antibiotics that affect the liver. The combination of amoxicillin and clavulanic acid in particular has a damaging potential.

According to the Drug Commission of the German Medical Association (AkdÄ), there are three possibilities for acute liver damage. Either the event is direct, dose-dependent and predictable, such as with paracetamol, or idiosyncratic, which means that the damage is unpredictable and occurs regardless of the dosage. Another mechanism mentioned by the AkdÄ is indirect acute liver damage, in which a drug activates the immune system and the damage to the liver only becomes apparent after a certain period of time. Causes include checkpoint inhibitors, for example.

The problem with recognizing liver damage caused by medication when it is not acutely noticeable is the ambiguous symptoms, which make diagnosis difficult. Doctors must first of all suspect that symptoms such as loss of appetite, vomiting, fever, joint, muscle and abdominal pain, as well as itching, stool and urine discoloration could be due to the liver-damaging side effect of a medication. PTAs can also pay attention here and at least point out this possibility if they suspect it. However, they must then refer the patient to a doctor; under no circumstances should patients stop their current medication on their own authority on the assumption that it could damage their liver.

Important: Not only chemical-synthetic but also herbal medicines and dietary supplements can damage the liver. This side effect often develops because patients overdose on a medication and/or take it for too long, writes the DGVS. The idea that “a lot helps a lot” still seems to be prevalent in the population. It is also the task of PTAs to point out from time to time that a medicine should really only be taken as prescribed.

This naturally applies to paracetamol in particular. Because many people swear by it for pain and buy it without a prescription, you can get into the habit of always explaining during the consultation that too high a dosage can cause acute damage to the liver, including liver failure. If the liver is so severely damaged that it stops working, many patients die as a result. According to AdkÄ, the toxicity of paracetamol to the liver is increased by fasting, malnutrition, alcohol and other drugs that induce the cytochrome P450 system.

As an antidote to paracetamol poisoning, N-acetylcysteine is particularly effective when administered orally or intravenously within eight hours of the paracetamol overdose. Because the breakdown of paracetamol in the liver produces quinonimine metabolites as liver-toxic substances, anything that increases the amount of endogenous glutathione helps, as this neutralizes the toxic substances. As a tripeptide, it is composed of cysteine, among other things, which is provided by N-acetylcysteine.