Amikacin !

A semisynthetic aminoglycoside that resists most bacterial inactivating enzymes; used for resistant gram-negatives and mycobacteria.

Updated 2026-11-01

Class: Aminoglycosides
Target: Decoding (A) site of the bacterial 16S rRNA, 30S ribosomal subunit
ATC code: J01GB06
WHO Model List of Essential Medicines

Decoding (A) site of the bacterial 16S rRNA, 30S ribosomal subunitAmikacin

The figure shows amikacin bound to a short RNA that reproduces the bacterial decoding site, not a whole ribosome.

Target in 3D: Decoding (A) site of the bacterial 16S rRNA, 30S ribosomal subunit. PDB structure 4P20 (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Like gentamicin, amikacin binds the decoding site of the 30S subunit and makes the ribosome misread mRNA. It is a derivative of kanamycin with a side chain that protects it from most aminoglycoside-modifying enzymes, so strains resistant to gentamicin and tobramycin often remain susceptible.

Enters the bacterium; its side chain shields it from modifying enzymes
Binds the 16S rRNA A site of the 30S subunit
mRNA misreading produces faulty proteins
Rapid bactericidal effect

Pharmacokinetics

Absorption: Given intravenously or intramuscularly; not absorbed by mouth.
Distribution: Extracellular fluid; protein binding is very low; it crosses the placenta and reaches the cerebrospinal fluid better when the meninges are inflamed.
Elimination: Unchanged in the urine by glomerular filtration.
Half-life: Slightly over 2 hours in adults with normal kidney function; longer in newborns and in kidney failure.

Indications

Serious infections by gram-negative bacilli resistant to gentamicin or tobramycin, including Pseudomonas. MRSA and other multidrug-resistant organism infections →
Bacterial septicemia, including neonatal sepsis. Neonatal sepsis →
Intra-abdominal infections such as peritonitis (with an anti-anaerobe drug). Peritonitis →
Part of combination regimens for mycobacterial infections, including tuberculosis. Tuberculosis →

Adverse effects

Common

Hearing loss starting at high frequencies, tinnitus
Rising creatinine and less urine
Rash, fever, headache, paresthesia

Contraindications

Hypersensitivity to amikacin
History of hypersensitivity or serious toxicity with another aminoglycoside

Key interactions

Loop diuretics: More ototoxicity.
Other nephrotoxic or neurotoxic drugs (vancomycin, polymyxins, cisplatin, other aminoglycosides): Added kidney and nerve damage.
Anaesthetics and neuromuscular blockers: Risk of prolonged paralysis and apnea.
β-lactams in the same solution: Mutual inactivation; given separately.

What is monitored

Peak and trough levels by protocol
Creatinine and urine output
Audiometry, especially in long mycobacterial treatments

Administration and safety

Intravenous infusion or intramuscular injection; not mixed with β-lactams in the same container.
Look-alike risk with other aminoglycosides and with similar-sounding names: check the drug name on every vial.
Level samples at the times the protocol sets.

Nursing care

Baseline creatinine, weight and hearing assessment before long courses.
Hydration and intake–output record.
Ask about tinnitus or muffled hearing at each shift; high-frequency loss may go unnoticed by the patient.
Teaching: report ringing, hearing change, dizziness, numbness or diarrhoea.

Pregnancy and breastfeeding

Amikacin crosses the placenta into the amniotic fluid; aminoglycosides can cause fetal harm, including deafness, so it is used only when the benefit justifies it.

Test yourself

Think of the answer, then tap the question to see it.

Why does amikacin often work against gram-negatives resistant to gentamicin?

Its side chain makes it a poor substrate for most aminoglycoside-modifying enzymes, the commonest resistance mechanism.

Which ear function does amikacin damage most?

Hearing (cochlear damage, starting at high frequencies), more than balance.

Besides resistant gram-negatives, which infections is amikacin used for?

Mycobacterial infections, including tuberculosis, always within combination regimens.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: DailyMed - AMIKACIN SULFATE injection, solution (DailyMed (U.S. National Library of Medicine), 2026); Amikacin Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 59 (McGraw Hill, 2023); RCSB PDB - 4P20: Crystal structures of the bacterial ribosomal decoding site complexed with amikacin (RCSB Protein Data Bank, 2026).

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Representative model, for educational purposes only.