An older client with rheumatoid arthritis is prescribed acetaminophen 3000-4000 mg daily. Which laboratory test should be monitored?

An older client with rheumatoid arthritis is prescribed acetaminophen 3000-4000 mg daily. Which laboratory test should be monitored?

• A. Liver function test (LFTs)
• B. Renal function test
• C. Complete blood count (CBC)
• D. Electrolyte panel

Answer: (A)

High daily doses of acetaminophen put the liver at risk. The liver handles most of its metabolism, and at higher amounts a toxic metabolite (NAPQI) can form. Normally, glutathione neutralizes this metabolite, but with large doses or impaired liver function, glutathione can be depleted and liver cells can be damaged, which shows up as raised enzymes and bilirubin on liver function tests. In an older person taking 3000–4000 mg daily, monitoring liver function helps detect early liver injury before symptoms appear. Baseline LFTs are useful, with periodic follow-up if high-dose therapy continues. Renal function, CBC, and electrolyte panels assess other systems and are not the primary tests for acetaminophen toxicity.

High daily doses of acetaminophen put the liver at risk. The liver handles most of its metabolism, and at higher amounts a toxic metabolite (NAPQI) can form. Normally, glutathione neutralizes this metabolite, but with large doses or impaired liver function, glutathione can be depleted and liver cells can be damaged, which shows up as raised enzymes and bilirubin on liver function tests. In an older person taking 3000–4000 mg daily, monitoring liver function helps detect early liver injury before symptoms appear. Baseline LFTs are useful, with periodic follow-up if high-dose therapy continues. Renal function, CBC, and electrolyte panels assess other systems and are not the primary tests for acetaminophen toxicity.