Gentamicin Unit Conversion

Gentamicin is an aminoglycoside antibiotic that displays broad spectrum, high potency, anti‑bacterial action for most susceptible organisms. At therapeutic serum concentrations ranging from 4 to 10 μg/mL (8.4 to 20.9 μmol/L), gentamicin is capable of inhibiting the growth of many gram positive cocci, especially penicillinase‑producing staphylococci. At concentrations of 10 μg/mL (20.9 μmol/L), most strains of E. coli, Proteus spp., Klebsiella, Aerobacter, Clostridium, Brucella spp., Salmonella, Serratia, and Shigella are inhibited. At concentrations ranging from 4 to 10 μg/mL (8.4 to 20.9 μmol/L), gentamicin displays activity against most strains of Pseudomonas aeruginosa. Because of these characteristics, gentamicin has been most successfully used in the treatment of serious infections, especially those caused by gram‑negative bacilli.

The therapeutic range of gentamicin should be measured at peak as well as trough concentrations. In patients with pre‑existing renal damage or those to whom gentamicin has been administered for prolonged periods or in doses above the therapeutic range, hearing impairment and/or nephrotoxicity may develop. Therefore, monitoring of peak and trough gentamicin levels is critical in the prevention of these serious complications with the adjustment of dosage administration as indicated.

Although optimum values may vary, peak serum values in the range of 6 to 10 μg/mL (12.5 to 20.9 μmol/L) and trough values in the range of 0.5 to 2.0 μg/mL (1.0 to 4.2 μmol/L) are generally accepted for therapeutic effectiveness. The achievement of non‑toxic, but therapeutic, serum levels is often difficult, even in patients with normal renal function. Complications encountered with the use of gentamicin are ototoxicity and nephrotoxicity. However, these reactions are predictable, and close patient monitoring is essential for the successful use of this agent. The most serious toxic effect of gentamicin is permanent damage to the vestibular division of the eighth cranial nerve, which has been reported to occur most frequently in patients with renal failure. Since gentamicin is inherently unstable, is not metabolized and is excreted primarily by glomerular filtration, toxic concentrations of the drug may accumulate in the body when the dosage is not adjusted for patients with impaired renal function. While high serum levels can be toxic, indiscriminately low dosages of gentamicin will result in ineffective treatment for many strains of gram‑negative bacteria. The indiscriminate use of low dosages of gentamicin may not only engender the emergence of gentamicin‑resistant organisms, but also the emergence of aminoglycoside‑resistant organisms. Current literature reflects increasing interest in once‑daily dosing versus the conventional administration of drug 2 to 4 times daily. Adoption of once‑daily dosing may require a revision of target peak and trough concentrations.