Clinical use
Therapeutic monitoring of blood gentamicin levels.
Background
Gentamicin is an aminoglycoside antibiotic that is used primarily to treat serious infectious diseases caused by gram-negative bacilli, by inhibiting protein synthesis. It can be used in combination with other antibiotics to treat serious infections such as bacteraemia, urinary tract infection, infective endocarditis, respiratory tract infection and neonatal sepsis.
Gentamicin has a narrow therapeutic range and therefore performing therapeutic drug monitoring is important to minimise renal toxicity and ototoxicity. Patients who are susceptible to the toxic effects of gentamicin usually have impaired renal function, receive high doses, are critically ill neonates or undergo prolonged gentamicin therapy.
For detailed instruction of how and when to take gentamicin levels and for the interpretation of gentamicin therapeutic drug level results, please refer to the Trust gentamicin guideline under the ‘Antibiotics serum level monitoring’ section. The policy can also be viewed MicroGuide which is downloadable as an app to smart phones.
Reference range
Therapeutic range in serum:
- Pre-dose (trough level) <1 mg/l
Specimen requirements
Gold top Serum separator or Heparinized Plasma
Sample request forms must state the following clinical information:
- Dosing schedule being used (dose and frequency of dosing interval)
- Time of last dose of antibiotic
- Time and date the level was taken
Limitations & restrictions
Do not send samples that have been stored at room temperature for longer than 8 hours.
Turnaround time
2 hours
Analysing laboratory
Biochemistry Lab, James Cook University Hospital, Marton Road, TS4 3BW