Homogeneous Immunoassays—Therapeutic Drug Monitoring
Innofluor®—Fluorescence Polarization Immunoassays To view and print the files below you will need Adobe Acrobat Reader®,
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INNOFLUOR® Amikacin Assay System
The INNOFLUOR® AMIKACIN Assay System is intended for the quantitative determination of total amikacin in serum for therapeutic drug monitoring by fluorescence polarization immunoassay (FPIA). The assay system is for use on the TDx® or the TDxFLx® (TDx®/TDxFLx®) analyzer.
Amikacin is one of the class of aminoglycoside drugs which are used in the treatment of serious enterococcal and gram-negative bacillary infections.1,2 The aminoglycosides inhibit bacterial protein synthesis by specifically binding to the 30 S ribosomal subunit.1,3,4 Amikacin is the aminoglycoside of choice for the treatment of infections caused by microorganisms resistant to other aminoglycosides, primarily gentamicin or tobramycin, due to its unique resistance to aminoglycoside-inactivating enzymes.1,4 Amikacin is routinely administered intravenously or intramuscularly, is rapidly dispersed into extracellular fluid, does not cross most cell membranes, and is essentially unbound to serum proteins.1,4,5 As with other aminoglycosides, amikacin is potentially ototoxic and nephrotoxic.1-6 In patients with normal renal function, amikacin is rapidly excreted, primarily by glomerular filtration, with an elimination half-life of approximately two hours.1-6 The use of amikacin in renal patients must be carefully monitored.1,3-6
Measurement of serum levels is necessary to prevent toxicity and inadequate dosing, due to wide individual variation in the elimination and distribution of amikacin.1,2,5,6
Suggested therapeutic amikacin levels for the peak specimen range from 20-25 µg/mL,3 however, recent literature cites a range for therapeutic peak levels of 20-30 µg/mL.1 Peak serum levels at concentrations greater than 30-35 µg/mL have been associated with nephrotoxicity, mainly tubular necrosis, and otoxicity, which includes damage to the vestibular and auditory branches of the eighth cranial nerve.3 Trough serum concentrations range from 5-10 µg/mL, and trough levels greater than 10 µg/mL have been associated with toxicity, 250 including renal failure, in some patients.1,13
Edson RS, Terrell CL. The aminoglycosides. Mayo Clin Proc 1991;66(11):1158-1164.
Reed LR II, et al. Pharmacokinetic monitoring of nephrotoxic antibiotics in surgical intensive care patients. Journal of Trauma 1989;29:1462-1470.
Anhalt JP. Interpretation of antimicrobial concentrations in serum. AACC Therapeutic drug monitoring continuing education and Q.C. program, April 1981:1-11.
Sande MA, Mandell GL. Antimicrobial agents. The aminoglycosides. In: The pharmacological basis of therapeutics, Goodman Gilman A. ed. Pergamon Press Inc., New York 10523 1990;1098-1116.
Sarubbi FA Jr., Hull JH. Amikacin serum concentrations: prediction of levels and dosage guidelines. Ann Intern Med 1978;89:612- 618.
Zaske DE, Strate RG, Kohls PR. Amikacin pharmacokinetics: wide interpatient variation in 98 patients. J Clin Pharmacol 1991;31:158-163.
