Normal dose paracetamol in muscular dystrophy patients - is it normal?

Area of Science:

• Pharmacology
• Hepatology
• Genetics

Background:

• Becker muscular dystrophy (BMD) is a genetic neuromuscular disorder.
• Paracetamol (acetaminophen) is a common analgesic and antipyretic.
• Liver injury can occur with paracetamol overdose.

Observation:

• A 16-year-old male with BMD presented with severe liver injury after ingesting paracetamol within recommended dosage guidelines.
• The patient exhibited significantly elevated alanine aminotransferase (ALT) and international normalized ratio (INR).
• Risk factors included malnutrition and the underlying muscular dystrophy.

Findings:

• Despite adhering to standard paracetamol dosing, the patient developed acute liver dysfunction.
• Treatment with N-acetylcysteine (NAC) for five days led to substantial improvement in liver enzymes and coagulation.
• ALT levels decreased from 5,599 to 652 U/L, and INR improved from 5.0 to 0.9.

Implications:

• This case highlights that standard paracetamol dosages may be toxic in patients with altered body composition and pharmacokinetics, such as those with muscular dystrophy.
• Physicians should consider individual patient factors, including nutritional status and underlying conditions, when prescribing paracetamol.
• Further research into paracetamol pharmacokinetics in specific patient populations is warranted to prevent iatrogenic liver injury.