Effects of medicines in liver dysfunction

Last updated: Thursday, June 13, 2019

As well as understanding how liver dysfunction can affect the way the body handles medicines, it is also important to consider how medicines can affect the liver. This depends on the type of liver disease, degree of hepatic dysfunction and what signs and symptoms the patient has, so needs to be considered for each individual patient.

Adverse effect profile  

Consider the potential for medicines to cause adverse reactions such as those described below when choosing or monitoring a medicine in a patient with liver dysfunction. You can read more about this subject via the SPS website, but example side effects that may be of concern include:

✦  Changes to LFTs 
Some drugs can cause mild, transient, insignificant rises in LFTs but this is not an absolute contraindication in patients with liver dysfunction. The risks and benefits of using the medicine need to be considered, being aware that changes may skew the monitoring of the pre-existing liver condition.

✦  Pruritus 
Patients with cholestatic liver disease often experience severe itch. Avoid drugs with a high incidence of urticaria or itching.

✦  Fatigue 
Patients with cholestatis and cirrhosis often suffer from tiredness. Encephalopathy can be made worse by medicines that cause sedation. Avoid drugs which cause drowsiness.

✦  Clotting abnormalities
As discussed earlier, patients with liver dysfunction may have impaired clotting. Drugs with an associated bleeding risk (anticoagulants, NSAIDs, antiplatelets) should only be used where the benefit outweighs the risk.

✦  Changes to electrolytes
Ascites can be made worse by increasing sodium levels. Avoid drugs which can increase sodium e.g. NSAIDs inhibit salt and water excretion. Consider the sodium content of drugs e.g. effervescent tablets, IV preparations. Encephalopathy can be precipitated by electrolyte disturbances.Drugs which can cause electrolyte disturbances should be used where the benefits outweigh the risks and with appropriate monitoring.

✦  Constipation
Encephalopathy can also be precipitated by constipation. • Gastrointestinal irritation - This can increase the bleeding risk in patients with varices. Avoid drugs that irritate the GI tract e.g. NSAIDs, bisphosphonates.

✦  Nephrotoxicity 
Certain types of liver disease increase the risk of developing renal impairment. Use nephrotoxic drugs with caution, and avoid if possible - especially in patients with hepatorenal syndrome.

Hepatotoxicity 

There are two types of hepatotoxicity: intrinsic, which is predictable, reproducible, dose-dependent, and idiosyncratic, which is unpredictable and independent of dose. The decision to use a drug with a hepatotoxicity risk depends on various factors:

  • The reported frequency and severity of hepatotoxicity 
  • Reversibility of liver damage. 
  • Clinical urgency of treating the condition concerned.
  • The other options available as treatment.

In general, patients with pre-existing liver disease are thought to be at no greater risk of drug-induced liver damage than the general population. There are a few exceptions to this rule (e.g. methotrexate, rifampicin). However, patients who have pre-existing liver disease may have less hepatic reserve to allow them to cope if hepatotoxicity occurs; therefore avoid drugs that have a high incidence of causing liver damage if at all possible.

Liver Transplant Patients 

Post-liver transplant, patients are the same as any other patient when considering the effect of medicines on liver function. If the patient has normal liver function, then there are no extra precautions to take.

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