Amoxicillin Blood Concentration in High-Dose Intravenous Discontinuous Amoxicillin: Look Beyond Numbers. Max-Amox...

Area of Science:

• Pharmacology
• Nephrology
• Infectious Diseases

Background:

• High-dose amoxicillin is crucial for severe infections like endocarditis.
• Amoxicillin can cause dose-dependent toxicities, notably crystal nephropathy.
• Monitoring amoxicillin trough plasma concentrations (ATPC) may prevent toxicity, but its routine use is understudied.

Purpose of the Study:

• To evaluate the distribution and variability of ATPC in patients receiving high-dose amoxicillin.
• To assess the clinical relevance of ATPC monitoring in routine practice.

Main Methods:

• Prospective clinical trial in adults receiving high-dose intravenous amoxicillin.
• Primary outcome: distribution of ATPCs over three days during the first week of treatment.
• Secondary outcomes: urine tests for amoxicillin crystalluria (AC), pH, and density.

Main Results:

• Seventy patients were included; high inter-individual variability in ATPC was observed.
• Amoxicillin crystalluria (AC) occurred in 47.8% of patients, increasing with urinary pH ≤ 6.
• Higher ATPCs were associated with AC and/or acute kidney injury.

Conclusions:

• High variability in ATPC suggests it's insufficient as a sole monitoring tool for amoxicillin dosage.
• Elevated ATPC, low urinary pH, and AC presence are indicators of potential iatrogenic effects.
• These findings may guide interventions like hydration, urine alkalinization, and dosage reduction.