Gentamicin

How it works

It binds irreversibly to the bacterial 30S ribosomal subunit, causing misreading of mRNA and inhibition of protein synthesis, producing a concentration-dependent bactericidal effect.

Prescribing in practice

• Nephrotoxicity and ototoxicity (vestibular and auditory) are the principal hazards and may be irreversible; use the lowest effective course and monitor closely, with particular caution in renal impairment and the elderly.
• Dosing is weight- and renal-function-based; consult local protocols and current prescribing references for the regimen and any therapeutic drug monitoring requirements.
• Avoid concurrent use with other nephrotoxic or ototoxic drugs, including loop diuretics, where possible.

Monitoring

Monitor renal function and serum gentamicin concentrations per local protocol, and assess for auditory or vestibular symptoms during prolonged therapy.

Counselling the patient

• Report any new hearing loss, ringing in the ears, dizziness or unsteadiness promptly.
• Maintain adequate hydration and tell the team about any kidney problems.

Evidence & guidelines

Aminoglycoside use is well established for serious Gram-negative sepsis and surgical prophylaxis, with MHRA and NICE guidance emphasising monitoring to limit nephro- and ototoxicity.