Liver Disease MDT Flashcards
What can affect drug absorption?
- Portal hypertension,
- Gastropathy,
- Ulcer of upper GI,
- Increased intestinal permeability,
- Impaired GI motility
What are the effects of liver disease on absorption of drugs
There may be reduce drug absorption in liver disease. Important to consider if the drug is lipid or water soluble. As lipid soluble drugs may be reliant on bile salts and so less absorbed in patients with cholestasis.
Drugs such as furosemide is delayed in patients with cirrhosis/ascites
What are the effects of liver disease on drug disribution
IS DRUG WATER OR LIPID SOLUBLE
In chronic liver disease there is reduced albumin synthesis. Therefore this can affects drugs which are highly protein bound, causing the level of free drug to increase.
If the drug is water soluble then it may distribute to ascites fluids, reducing the concentration of drug in other areas including the site of action.
What are the effects of liver disease of drug metabolism?
In liver disease there may be reduced blood flow across liver. There may be reduced activity/expression of drug metabolising enzymes and therefore reduced clearance of drug. Consideration needs to be made about whether the drug is metabolised by the liver and if there is first pass metabolism.
What are the effects of liver disease on excretion of drugs
Depends whether drug is excreted by the liver or kidneys or biliary. In advanced cirrhosis there may be renal impairment
Describe problems with paracetamol prescribing in liver disease
Glutathione is required to block the formation of acetaminophen’s toxic metabolite. However glutathione is reduced in individuals with cirrhosis of malnutrition. This may increase paracetamol half life by 2 fold. However paracetamol is generally well tolerated as long as you do not exceed 2g/day
When should you avoid prescribing paracetamol?
In patients with advanced chronic liver disease/ cirrhosis who are actively consuming alcohol, malnourished or not eating properly or receiving many drugs metabolised by liver.
When should you avoid prescribing tramadol?
In patients with decompensated liver cirrhosis or patients at risk of seizures (think about hepatic encephalopathy- note all opioids can worsen hepatic encephalopathy)
What opioid can be useful in patients with renal failure and cirrhosis?
Alfentanil
What drug preparations should be avoided in liver disease
Prolonged release
What opioid is the preferred drug in liver disease
Morphine as it is short acting and safe. Other opioids like codeine, dihydrocodeine or tramadol can have an unreliable metabolism in decompensated liver cirrhosis.
