P01 An evaluation of vancomycin therapy in paediatric patients post guideline change
Authors: Agbonin Adedoyin , Crook Joanne 
Published: August 2020

Aim

To evaluate the prescribed dose of vancomycin as per local guideline and review the achieved therapeutic drug levels.

Method

Retrospective data was collected from paediatric inpatients that were prescribed vancomycin for more than 24 hours during the audit period. Data was obtained from the Trust’s electronic prescribing system, LastWord. Measured standards included initial vancomycin dose, dose prescribed for renal impairment, time to first trough level and any required dose adjustments as per local guidance. The dose bands for each age group were1; birth - 6 months 15 mg/g 8 hourly; >6 months -12 months 20 mg/kg 8 hourly; >12 months – 12 years 25 mg/kg 8 hourly; >12 years 20 mg/kg 8 hourly. The number of patients achieving therapeutic vancomycin trough levels was recorded. Safety data was collected, including reported adverse effects, infusion related reactions and renal impairment. Renal impairment was defined as an increase in creatinine by 50%. Data was collected from April 2018 for 6 months. Relevant data with regards to patient demographics, dosing and drug levels were collected and analysed using Microsoft Excel.

Results

12 patients received 15 doses of vancomycin over 6 months. 67% of initial vancomycin doses were prescribed as per local guideline, 60% of therapeutic trough levels were taken at the right time and 71% of patients that were prescribed the correct dose and had levels taken at the right time achieved therapeutic trough levels. 12 patients required dose adjustments. One patient with renal impairment was not prescribed the recommended dose as per local guidance. One patient reported an infusion related reaction, which was overcome by increasing the infusion time. Two patients who received therapy for >7 days accumulated vancomycin and recorded high trough levels, with no adverse events. One patient reported an increase in creatinine by 50% over the treatment period.

Conclusions

Vancomycin has the potential to induce nephrotoxicity and ototoxicity when consistently at high serum drug levels. Due to its narrow therapeutic index, drug levels should be monitored to ensure the drug does not accumulate. The licensed dose and dose listed in the BNF for Children 2 3 has historically under dosed patients at our trust, leading to the risk of ineffective therapy and bacterial resistance. It is unclear from research what the optimal dose is for paediatric patients.

More research is needed to determine the correct paediatric dose of vancomycin. Higher doses than currently recommended as per licence resulted in three quarters of patients achieving therapeutic levels, however 12 patients still required dose adjustment. No patients suffered irreversible adverse effects or toxicity, suggesting that higher doses are safe to use in the paediatric population. Further education is required for those involved in the prescribing, administering and monitoring of Vancomycin in paediatric patients to ensure its safe use. Additional monitoring is required for those receiving higher doses >7 days to prevent drug accumulation, alternatively a loading dose followed by lower maintenance dose may be a more suitable dosing regimen.

References

Hughes S, Crook J, Ross J. Vancomycin intravenous dosing guideline - paediatrics. Chelsea and Westminster Hospital; 2017.

Stockman C, Sammons H, Stakey E, et al. Unanswered Questions Regarding Optimal Pediatric Vancomycin Use. Therapeutic Drug Monitoring 2016; 38:491–420.

National Institute for Health and Care Excellence. Vancomycin. Available from https://bnfc.nice.org.uk/drug/vancomycin.html [Accessed 10th Oct 2018]