Antimicrobials/Aminoglycoside

Aminoglycosides

also: gentamicin · amikacin · tobramycin

Overview

Potent Gram-negative bactericidals — severe sepsis, but nephro/ototoxic, so levels and renal function must be monitored.

Mechanism

Bind the 30S ribosomal subunit → misreading of mRNA → bactericidal. Concentration-dependent killing → once-daily dosing.

The agents

Gentamicinaminoglycoside

once-daily, levels

Gram− sepsis, pyelonephritis, endocarditis (synergy).

Amikacinaminoglycoside

Gentamicin-resistant Gram−; some mycobacteria.

Adverse effects

Nephrotoxicity (usually reversible)serious

Monitor renal function + levels.

Ototoxicity (irreversible — vestibular + cochlear)serious

Neuromuscular blockadecommon

Worsens myasthenia gravis.

Cautions & contraindications

Pregnancypregnancy

Fetal ototoxicity.

Myasthenia gravisall

Neuromuscular blockade.

Renal impairment (caution + dose by levels)renal

Interactions

Loop diuretics (ototoxicity), other nephrotoxins, vancomycin

Monitoring & kinetics

Trough levels + renal function (and peak if endocarditis/synergy)

IV/IM (not absorbed orally). Once-daily; monitor levels.

Choosing it

Spectrum: Gram-negatives incl. Pseudomonas; synergy with β-lactams for Gram-positive endocarditis. NO anaerobe / atypical cover; poor in acidic/abscess environments.

Source: BNF — Aminoglycosides