Gentamicin and Vancomycin: Reducing Patient Risk

Gentamicin and vancomycin have a narrow therapeutic index i.e. efficacy or the risk of toxicity or treatment failure is related to small changes in concentration of the drugs and hence the accuracy of the dosing. In addition, gentamicin accumulates in the inner ear risking oto-vestibular toxicity if prolonged or recurrent treatment courses. Consequently, accurate prescribing, appropriate therapeutic drug monitoring (TDM) and, in the case of gentamicin, restricted duration of therapy and avoidance of repeat courses are important to minimise risk.

NOTE: Before prescribing these agents ensure you refer to the correct dosing and monitoring guidance and use the correct prescription and monitoring documentation.

• Gentamicin: used and prescribed in 3 distinct ways within NHSGGC adult antimicrobial policy
  • Treatment dose (see the Gentamicin Dosing Guidelines).
  • Synergistic low dose for endocarditis (see Synergistic Gentamicin for Endocarditis in Adults on the NHSGGC Clinical guideline Platform). 
  • Surgical prophylaxis dose (see the Secondary Care- Prophylaxis section on the NHSGGC Clinical Guideline Platform)
• Vancomycin: used and prescribed in 3 distinct ways within NHSGGC adult antimicrobial policy:
  • Pulsed IV Infusion: see the Vancomycin Intermittent IV Infusion dosing guidance
  • Continuous IV Infusion: see the Vancomycin Continuous IV infusion dosing guidance.
  • Oral vancomycin for the local treatment of C. difficile infection. Oral vancomycin is not absorbed and cannot be used to treat a systemic infection.

Guideline updated: March 2025

Page updated: April 2025