What are the signs of toxicity to look for in patients receiving therapeutic drug monitoring for aminoglycosides?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 22 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

Signs of toxicity to monitor in patients receiving aminoglycosides include:

  • Nephrotoxicity: Look for rising serum creatinine and reduced urine output, indicating acute kidney injury. Aminoglycosides accumulate in renal proximal tubular cells causing nephrotoxicity, which is often reversible if detected early .
  • Ototoxicity: Monitor for symptoms such as tinnitus, hearing loss, vertigo, or imbalance. These signs reflect cochlear and vestibular toxicity, which may be irreversible if not identified promptly .
  • Neuromuscular blockade: Although rare, watch for muscle weakness or respiratory depression, especially in patients with underlying neuromuscular disorders or those receiving concurrent neuromuscular blocking agents .
  • Laboratory monitoring: Therapeutic drug monitoring (TDM) aims to maintain aminoglycoside serum concentrations within a therapeutic range to avoid toxicity. Elevated trough levels correlate with increased risk of nephro- and ototoxicity .

Regular clinical assessment combined with TDM is essential to detect early toxicity signs and adjust dosing accordingly to prevent permanent damage ; . In neonates, particular vigilance is required due to immature renal function and increased susceptibility to toxicity .

Educational content only. Always verify information and use clinical judgement.