Therapeutic Drug Monitoring of Gentamicin in a Patient with Delayed Wound Healing

Gentamicin, used for the treatment of serious gram-negative infections, has a narrow therapeutic index. This property may lead to several side effects, thus, therapeutic drug monitoring (TDM) is important in gentamicin therapy.

This chapter aims to report the pharmacokinetics of gentamicin when using a once-daily dosing regimen.

The patient, a 78-year-old male, weighed 78 kg and was 1.75 m tall. He was brought into the hospital with a wound infection brought on by chronic limb ischaemia. A once-daily dosing of gentamicin (360 mg by infusion over 30 minutes) in combination with flucloxacillin was prescribed to this patient. A gentamicin blood sample was taken every day for four days: Day 1 = 1.4 mg/L, Day 2 = 2.1 mg/L, Day 3 = 2.1 mg/L, Day 4 = 1.6 mg/L. The patient’s serum creatinine was 88 µmol/L during the four days. To determine the dosage and interval for gentamicin administration, the Hartford nomogram was employed. A once-daily dosing regimen of gentamicin can lead to the clinical and bacteriological cure of infection. In addition, the Hartford nomogram is a reliable tool for keeping track of gentamicin's once-daily dose schedule.