[9][1] Amikacin works by blocking the function of the bacteria's 30S ribosomal subunit, making it unable to produce proteins.
[9] Amikacin is most often used for treating severe infections with multidrug-resistant, aerobic Gram-negative bacteria, especially Pseudomonas, Acinetobacter, Enterobacter, E. coli, Proteus, Klebsiella, and Serratia.
[9] A liposome inhalation suspension is also available and approved to treat Mycobacterium avium complex (MAC) in the United States,[20][5] and in the European Union.
[20] The US Food and Drug Administration (FDA) granted the application for amikacin liposome inhalation suspension fast track, breakthrough therapy, priority review, and qualified infectious disease product (QIDP) designations.
[20] By the sixth month of treatment, 29 percent of patients treated with amikacin liposome inhalation suspension had no growth of mycobacteria in their sputum cultures for three consecutive months compared to 9 percent of patients who were not treated with amikacin liposome inhalation suspension.
[21] Infants also tend to have a larger volume of distribution due to their higher concentration of extracellular fluid, where aminoglycosides reside.
[23] In people with muscular disorders such as myasthenia gravis or Parkinson's disease, amikacin's paralytic effect on neuromuscular junctions can worsen muscle weakness.
The resulting effects of neurotoxicity include vertigo, numbness, tingling of the skin (paresthesia), muscle twitching, and seizures.
It easily ionizes to a cation and binds to the anionic sites of the epithelial cells of the proximal tubule as part of receptor-mediated pinocytosis.
[25] Nephrotoxicity is more common in those with pre-existing hypokalemia, hypocalcemia, hypomagnesemia, acidosis, low glomerular filtration rate, diabetes mellitus, dehydration, fever, and sepsis, as well as those taking antiprostaglandins.
[9] Rare side effects (occurring in fewer than 1% of users) include allergic reactions, skin rash, fever, headaches, tremor, nausea and vomiting, eosinophilia, arthralgia, anemia, hypotension, and hypomagnesemia.
[14][17] The amikacin liposome inhalation suspension prescribing information includes a boxed warning regarding the increased risk of respiratory conditions including hypersensitivity pneumonitis (inflamed lungs), bronchospasm (tightening of the airway), exacerbation of underlying lung disease and hemoptysis (spitting up blood) that have led to hospitalizations in some cases.
[20][5] Other common side effects in patients taking amikacin liposome inhalation suspension are dysphonia (difficulty speaking), cough, ototoxicity (damaged hearing), upper airway irritation, musculoskeletal pain, fatigue, diarrhea and nausea.
Such drugs include other aminoglycosides; the antiviral acyclovir; the antifungal amphotericin B; the antibiotics bacitracin, capreomycin, colistin, polymyxin B, and vancomycin; and cisplatin, which is used in chemotherapy.
[9] The effect of amikacin is increased when used with drugs derived from the botulinum toxin,[17] anesthetics, neuromuscular blocking agents, or large doses of blood that contains citrate as an anticoagulant.
[14] Amikacin evades attacks by all antibiotic-inactivating enzymes that are responsible for antibiotic resistance in bacteria, except for aminoacetyltransferase and nucleotidyltransferase.
[28] This is accomplished by the L-hydroxyaminobuteroyl amide (L-HABA) moiety attached to N-1 (compare to kanamycin, which simply has a hydrogen), which blocks the access and decreases the affinity of aminoglycoside-inactivating enzymes.
[31] Resistance to amikacin and kanamycin in Mycobacterium, the causative agent of tuberculosis, is due to a mutation in the rrs gene, which codes for the 16S rRNA.
[9] In infants, amikacin is normally found at 10–20% of plasma levels in the spinal fluid, but the amount reaches 50% in cases of meningitis.
[9][16] Factors that cause amikacin to be excreted via urine include its relatively low molecular weight, high water solubility, and unmetabolized state.
[8] In dogs and cats, amikacin is commonly used as a topical antibiotic for ear infections and for corneal ulcers, especially those that are caused by Pseudomonas aeruginosa.
[40] It is also used in topical medication for the eyes and arthroscopic lavage; when combined with a cephalosporin, is used to treat subcutaneous infections that are caused by Staphylococcus.