What are the recommended therapeutic drug monitoring guidelines for gentamicin in adult patients?

Therapeutic drug monitoring (TDM) for gentamicin in adult patients primarily involves measuring trough and, in selected cases, peak blood concentrations to optimise efficacy while minimising toxicity. The trough concentration should be measured immediately before the second dose and before every subsequent third dose, with the goal of maintaining trough levels below 2 mg/L, and if treatment extends beyond three doses, aiming for trough concentrations below 1 mg/L to reduce nephrotoxicity risk NICE NG195. Peak concentrations, typically measured 1 hour after administration, may be considered in adults with factors such as oedema, high body weight, unsatisfactory clinical response, or confirmed Gram-negative infections, with a target peak concentration generally above 8 mg/L to ensure bactericidal activity NICE NG195. Dose intervals should be adjusted based on trough levels and renal function, and doses should not be withheld solely due to delays in trough measurement unless there is evidence of renal impairment NICE NG195.

Recent literature supports the use of computerised dose recommendation and decision support systems to improve compliance with these TDM guidelines, enhancing dosing accuracy and patient safety Diasinos et al. 2015. Additionally, optimisation of aminoglycoside dosing, including gentamicin, in complex infections such as cystic fibrosis pulmonary exacerbations highlights the importance of individualized TDM to balance efficacy and toxicity Young et al. 2013. Therefore, integrating guideline-based TDM with technological support and clinical judgement is recommended for adult patients receiving gentamicin.