Cefazolin-induced hypoprothrombinemia.

Area of Science:

• Pharmacology
• Nephrology
• Hematology

Background:

• Acute renal failure (ARF) complicates management of infections, increasing risk of adverse drug events.
• Cefazolin is a commonly used antibiotic, but its potential to cause hypoprothrombinemia, especially in renal impairment, is not well-recognized.

Observation:

• A 50-year-old woman with ARF and postsurgical wound infection received intravenous cefazolin.
• After seven days of cefazolin therapy, her International Normalized Ratio (INR) increased from 1.3 to 4.0, indicating significant hypoprothrombinemia.
• The patient experienced bleeding and hypotension, prompting vitamin K administration, which normalized her INR.

Findings:

• The Naranjo et al. scale indicated a probable causal relationship between cefazolin administration and the development of hypoprothrombinemia.
• No other medications or conditions were identified that could explain the observed coagulopathy.

Implications:

• This case underscores the potential for cefazolin to induce hypoprothrombinemia, particularly in patients with compromised renal function.
• Clinicians should consider monitoring prothrombin time (INR) in patients receiving prolonged cefazolin therapy, especially those with renal failure.
• Early recognition and management with vitamin K can effectively reverse cefazolin-induced hypoprothrombinemia.