Gentamicin prescribing improved through electronic prescribing protocols

Background

Gentamicin is an aminoglycoside antibiotic, with a narrow-therapeutic index and known to cause serious dose related side effects such as nephrotoxicity and irreversible ototoxicity. Therefore, ensuring that dosing and monitoring is done correctly is important.

Previous audits identified issues with prescribing of gentamicin in the trust since changing to an electronic prescribing and medicines administration (EMPA) system. This prompted a new method for prescribing using renal function to estimate the initial frequency of dosing. The frequency is then confirmed using a serum gentamicin level. This method was introduced in November 2022.

Objectives

To evaluate the new method of prescribing gentamicin as part of a quality improvement cycle.

Audit standards:

• Gentamicin dose is correct 100% of the time
• Gentamicin levels are taken correctly 90% of the time
• Initial gentamicin dosing frequency matches actual frequency 80%.

Methods

A random sample of patients prescribed gentamicin was taken from December 2023 to January 2024. Using the previous data collection tool, clinical systems were used to collect height, weight, serum gentamicin levels, and creatinine. The EPMA system was used to collect information on the dosing and frequency including the timing of the dose. The Cockcroft & Gault equation was used to calculate creatine clearance.

Results

The audit found dosing of gentamicin improved, with 90% (43/48) of patients now prescribed the correct dose, compared with 64% (54/85) from the previous audit.

However, there was a reduction in levels being taking at the correct time: 67% (32/48) of levels were taken at the correct time compared with 86% (73/85) from the previous audit. Sixteen patients did not have serum gentamicin levels taken, the main reason being treatment was ceased after the first dose (9 patients).

Of the 32 patients who had their levels taken, their initial dosing frequency, based on their calculated renal function, matched the dosing frequency based on the level in 78% (25/32) of the patients. This was slightly lower than the 80% from the previous audit, although could have been influenced by the reduction in levels taken.

Conclusion

Compared to the previous audit on gentamicin prescribing there was an improvement in dosing. However, appropriate taking of serum gentamicin levels has reduced, which could be a potential negative impact of the new protocol and how levels are displayed on the EPMA system. Using renal function to estimate dosing interval was accurate in 78% of cases and can provide some assurances especially when levels aren’t taken correctly. More work is required to train staff about the additional reminders on the EPMA chart.

Additional authors: Sohail Khan, Mid Yorkshire Teaching NHS Trust

The opinions expressed in this article are those of the author. They do not purport to reflect the opinions or views of the UKCPA or its members. We encourage readers to follow links and references to primary research papers and guidance.

Competing interest statement:

The author declares: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.