Aminoglycoside

Amikacin

An aminoglycoside made from kanamycin, used for serious Gram-negative infections, often gentamicin-resistant, and for drug-resistant TB.

Drug card

Class: Aminoglycoside
How it works: Binding the 30S subunit so mRNA is misread and faulty proteins are made
Used for: Serious Gram-negative infections and sepsis
Complicated or recurrent urinary tract infections
High-risk febrile neutropenia
Multidrug-resistant tuberculosis
Known for: Hearing loss, starting with high tones, often permanent
Kidney injury (nephrotoxicity)

Study it as a flashcard, and it comes back before you forget it.

Mechanism of action

How does amikacin work?

Amikacin is a semisynthetic aminoglycoside made from kanamycin A. It binds the bacterial 30S ribosomal subunit and is bactericidal, but it resists several of the enzymes bacteria use to inactivate gentamicin and tobramycin, so many strains resistant to those drugs stay sensitive. Nearly all of it leaves the body unchanged in the urine.

Like other aminoglycosides: Aminoglycosides bind the 16S rRNA of the bacterial 30S ribosomal subunit, so the ribosome misreads mRNA and builds faulty proteins, and the bacteria die. Killing grows with peak concentration and goes on after levels fall (a post-antibiotic effect), which suits once-daily dosing. Anaerobes resist them, and with a cell wall agent such as a penicillin they act synergistically.

Uses

What is amikacin used for?

Serious Gram-negative infections and sepsis
Complicated or recurrent urinary tract infections
High-risk febrile neutropenia
Multidrug-resistant tuberculosis
Serious respiratory tract infections
Peritonitis and other abdominal infections

Side effects

Side effects of amikacin

Hearing loss, starting with high tones, often permanentKnown forSerious
Kidney injury (nephrotoxicity)Known forSerious
Neuromuscular blockade and breathing paralysisSerious
Numbness, tingling and muscle twitching
SeizuresSerious
Low magnesium (hypomagnesemia)
Deafness in babies exposed in the wombSerious
C. difficile colitisSerious
Allergic reactions, rash and drug fever
Bronchospasm (inhaled form or sulfite allergy)Serious
Hoarse voice and cough (inhaled form)
Hypersensitivity pneumonitis (inhaled form)Serious

Known for marks what an exam expects you to know it for.

Watch for

Cautions and what sets it apart

Monitor blood levels, kidney function and hearing tests; high-tone hearing loss can start silently and appear after the course ends.
Avoid with furosemide, vancomycin, cisplatin, amphotericin B, colistin or other aminoglycosides, which add ear and kidney toxicity.
Avoid in myasthenia gravis; with anesthetic muscle relaxants it can deepen neuromuscular block and stop breathing.
Inhaled liposomal amikacin can cause bronchospasm, hemoptysis and pneumonitis and can worsen the underlying lung disease.

Good to know: Amikacin mainly damages hearing rather than balance. An inhaled liposomal form is licensed for Mycobacterium avium complex (MAC) lung disease that persists after 6 months of standard treatment.

Remember it

A way to remember it

Aminoglycosides caNNOT kill anaerobes.

The capital letters N, N, O, T recall nephrotoxicity, neuromuscular blockade, ototoxicity and teratogenicity (deafness in the fetus); the phrase itself is a reminder that anaerobes resist them.

A mnemonic widely used in teaching

Its class

Aminoglycosides

Other aminoglycosides with a card:

Gentamicin

Easily mixed up with tetracyclines and glycopeptides.

All about aminoglycosides

Sources

Checked against

Written for biofideX in plain words, after checking these references:

For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.

Practice it

Antibiotics: protein synthesis

Amikacin is one of 10 drugs practiced together here: their classes, how they work, what they treat and what they're known for.

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