Targeting Lower Serum Trough Concentrations: A New Gentamicin Dosing Strategy for Suspected Neonatal Early-Onset Sepsis

OBJECTIVE

Neonatal gentamicin dosing algorithms are not designed to achieve serum trough concentrations ≤1 mcg/mL. The purpose of our study was to evaluate a new gentamicin algorithm based on serum creatinine (SCr) and gestational age (GA) designed to achieve serum gentamicin trough concentrations ≤1 mcg/mL.

METHODS

A retrospective cohort study was conducted in a level IIIB neonatal intensive care unit. The incidence of elevated serum gentamicin troughs for this study was compared with the center's previously published results to evaluate the proposed dosing algorithm. Patients were included if gentamicin was administered within the first 7 days of life and a serum gentamicin trough concentration and a baseline SCr concentration were obtained. Patients were further subdivided into groups based on GA for data analysis: ≤30 weeks (group 1), 30-34 weeks (group 2), and ≥35 weeks (group 3). The SCr was considered mildly elevated (0.81-0.99 mg/dL) or elevated (≥1 mg/dL). The respective outcomes between the post-algorithm and control groups were examined using intention-to-treat analysis and Bayesian modeling to calculate rate differences.

RESULTS

Of the 2377 patients evaluated, 366 met the inclusion criteria. Significantly lower percentages of elevated serum gentamicin troughs were noted in groups 2 and 3 subsequent to the implementation of the dosing algorithm with 16% and 15% lower rate differences, respectively. Regardless of GA, there were significantly fewer elevated serum troughs in the post-implementation groups than in the control with mildly elevated and elevated SCr p < 0.001.

CONCLUSIONS

Using a dosing algorithm based on SCr significantly reduced the number of elevated serum trough rates in neonates with a GA greater than 30 weeks.

Antibiotic-related adverse events in paediatrics: unique characteristics

Introduction: Antibiotics have saved and are still saving countless human lives from the burden of infectious diseases. However, as with all other drugs, they can cause adverse events. Generally, these are uncommon, mild and spontaneously resolving. However, in some cases, they can cause relevant clinical problems. Compared with adults, children, particularly in the first years of life, have a higher risk of antibiotic-related adverse events for several reasons. Areas covered: In this paper, the conditions that can contribute to the elevated risk of antibiotic-related adverse events in children are discussed. Expert opinion: Antibiotic stewardship can be a solution to limit antibiotic abuse and misuse and consequently the incidence of antibiotic-related adverse events in children. Moreover, most of the antibiotic-associated adverse events can be avoided with more extensive pre-marketing medicine investigations, improved postmarket safety surveillance system, increased transparency throughout the clinical research enterprise, increased training of clinical pharmacologists and paediatric researchers, expanded pool of paediatric patients, and providing additional funding and incentives for paediatric drug development.

Experience With Prophylactic Gentamicin During Penile Prosthesis Surgery: A Retrospective Comparison of Two Different Doses

BACKGROUND

Gentamicin has been determined to be active against a wide range of bacterial infections and has been commonly used as a preoperative antibiotic for inflatable penile prosthesis (IPP) implantation. However, the best dosing regimen to produce the safest optimal prophylactic effect remains to be determined.

AIM

To compare low- and high-dose gentamicin as prophylaxis during IPP implantation.

METHODS

We retrospectively analyzed two groups of patients who underwent IPP placement from April 14, 2012 through April 13, 2016. Group 1 was composed of 490 patients who underwent IPP placement from April 14, 2012 through April 13, 2014 and received a low dose of preoperative gentamicin at 80 mg every 8 hours for 1 day. Group 2 was composed of 407 patients who underwent IPP placement from April 14, 2014 through April 13, 2016 and received a single high dose of preoperative gentamicin at 5 mg/kg. We compared the infection rates of IPP and any gentamicin-related toxicities. The same surgeon performed all procedures. All patients received additional vancomycin 1 g before incision and at 12 hours postoperatively.

OUTCOME

Demographic data and IPP infection rate were compared and potential toxicities from the higher dose of gentamicin were closely monitored.

RESULTS

There were no significant differences in mean age, mean body mass index, and mean interval for IPP placement and IPP infection between the two groups. No toxicity was seen with the higher gentamicin dose. Six cases in group 1 (five de novo cases and one redo case, infection rate = 1.22%) and three cases in group 2 (two de novo cases and one redo case, infection rate = 0.74%) were found to have IPP infection. The infection rate in group 2 appeared to be lower than that in group 1, although a significant statistical difference was not achieved (P = .057).

CLINICAL IMPLICATIONS

These findings would help guide urologists in choosing an optimal preoperative gentamicin dose for IPP surgery.

STRENGTHS AND LIMITATIONS

This is the first study to report on the usage of high-dose preoperative gentamicin for IPP surgery but with limitations as a retrospective study.

CONCLUSIONS

Although not achieving a statistical difference, there was a trend for patients receiving a higher dose of preoperative gentamicin to have a lower IPP infection rate. No toxicity was encountered from the 5-mg/kg gentamicin dose. We recommend following prophylactic high-dose gentamicin guidelines. Xie D, Gheiler V, Lopez I, et al. Experience With Prophylactic Gentamicin During Penile Prosthesis Surgery: A Retrospective Comparison of Two Different Doses. J Sex Med 2017;14:1160-1164.

Should gentamicin trough levels be routinely obtained in term neonates?

OBJECTIVE

Gentamicin is a common antibiotic used to treat sepsis in neonates. We hypothesize that obtaining routine gentamicin trough levels may not be necessary in low-risk, term infants.

STUDY DESIGN

We performed a retrospective cohort study of term infants (n=346) treated with gentamicin in a single level III neonatal intensive care unit (NICU). The results of gentamicin trough levels and the correlation with risk factors and potential side effects were recorded. In addition, we conducted a survey of 75 academic NICUs across the United States regarding their gentamicin monitoring practice.

RESULTS

Routine trough levels did not predict potential gentamicin toxicity in neonates with low risk factors. Regression analysis demonstrated a positive correlation between gentamicin trough levels and serum creatinine. The survey of the NICUs in the United States demonstrated significant inconsistency in gentamicin monitoring practice.

CONCLUSION

Obtaining gentamicin trough levels guided by risk factors is more appropriate than obtaining routine trough levels in low-risk term neonates.

Identification of Risk Factors for Elevated Neonatal Gentamicin Trough Concentrations

OBJECTIVES: The objective of this study was to identify neonatal and maternal characteristics that may be associated with elevated neonatal gentamicin trough concentrations despite application of a previously published gentamicin dosage strategy.

METHODS: Retrospective cohort study of all neonates admitted to University of Vermont Medical Center (562-bed academic teaching hospital, Burlington, VT) receiving gentamicin between June 1, 2009, and August 31, 2013. A total of 205 neonates were included, with 41 cases and 164 controls.

RESULTS: Postmenstrual age (PMA, gestational age plus chronological age) and small-for–gestational age (SGA) status were independently associated with elevated neonatal gentamicin trough concentrations. No maternal risk factor evaluated remained significantly associated in the multivariate analysis.

CONCLUSIONS: The probability of an elevated gentamicin trough concentration increases with lower PMA and is further accentuated in neonates with SGA status. In contrast, the presence of maternal risk factors did not increase the likelihood of elevated gentamicin trough concentrations. Neonates with lower PMA and SGA status may require an individualized dosage and monitoring strategy.