Gentamicin usage in newborns--a simple and practical regime

Extended-interval Dosing of Gentamicin in Premature Neonates Born at <32 Weeks' Gestation and >7 Days of age

PURPOSE

Extended-interval dosing (EID) regimens of gentamicin have been validated for treating confirmed or suspected early- and late-onset sepsis in preterm infants in the first week of life. Despite the marked changes in volume of distribution and renal clearance in preterm infants after the first few days of life, few studies have validated EID regimens of gentamicin in this population. The objective of the study was to evaluate an EID regimen of gentamicin in infants born at <32 weeks' gestational age and aged >7 days.

METHODS

This observational study of an EID regimen was conducted in 39 infants. Dosing interval was based on the serum drug concentration at 22 hours after the administration of the first dose of 5 mg/kg. Gentamicin peak (5-12 µg/mL) and trough (<2 µg/mL) levels were compared to those in a historical control group of 39 infants who received traditional-interval dosing (TID) of 2.5 mg/kg of gentamicin with dosing intervals of 8, 12, or 24 hours.

FINDINGS

There were no differences in birthweight, gestational age at birth, postmenstrual age, weight at the start of gentamicin administration, postnatal age, small for gestational age status, antenatal corticosteroid use, or postnatal indomethacin exposure between the 2 groups. In the EID group, dosing intervals were 24 hours in 30 infants, 36 hours in 6 infants, and 48 hours in 3 infants. Compared with the TID group (n = 39), the EID group had a significantly higher peak level (median, 9.0 vs 4.7 µg/mL) and a significantly lower trough level (median, 0.7 vs 1.1 µg/mL) (both, P < 0.001). On regression analysis, the postmenstrual age was correlated significantly with trough levels in the EID group. There was no adverse effect on renal function in either group. On follow-up, 1 infant in the EID group and 2 infants in the TID group had evidence of sensorineural hearing loss.

IMPLICATIONS

In infants born at <32 weeks' gestation and >7 days of age, an EID gentamicin regimen, with a dosing interval based on a single concentration measurement at 22 hours after the administration of the first dose, achieved therapeutic peak and trough levels and performed significantly better than did a TID regimen in reaching target peak and trough levels. Larger-scale trials are needed for assessing the clinical efficacy (treatment failure/success) of these regimens.

One dose per day compared to multiple doses per day of gentamicin for treatment of suspected or proven sepsis in neonates

BACKGROUND

Animal studies and trials in older children and adults suggest that a 'one dose per day' regimen of gentamicin is superior to a 'multiple doses per day' regimen.

OBJECTIVES

To compare the efficacy and safety of one dose per day compared to multiple doses per day of gentamicin in suspected or proven sepsis in neonates.

SEARCH METHODS

Eligible studies were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 3) in the Cochrane Library (searched 8 April 2016), MEDLINE (1966 to 8 April 2016), Embase (1980 to 8 April 2016), and CINAHL (December 1982 to 8 April 2016).

SELECTION CRITERIA

All randomised or quasi-randomised controlled trials comparing one dose per day ('once a day') compared to multiple doses per day ('multiple doses a day') of gentamicin to newborn infants.

DATA COLLECTION AND ANALYSIS

Data collection and analysis was performed according to the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

Eleven RCTs were included (N = 574) and 28 excluded. All except one study enrolled infants of more than 32 weeks' gestation. Limited information suggested that infants in both 'once a day' as well as 'multiple doses a day' regimens showed adequate clearance of sepsis (typical RR 1.00, 95% CI 0.84 to 1.19; typical RD 0.00, 95% CI -0.19 to 0.19; 3 trials; N = 37). 'Once a day' gentamicin regimen was associated with fewer failures to attain peak level of at least 5 µg/ml (typical RR 0.22, 95% CI 0.11 to 0.47; typical RD -0.13, 95% CI -0.19 to -0.08; number needed to treat for an additional beneficial outcome (NNTB) = 8; 9 trials; N = 422); and fewer failures to achieve trough levels of 2 µg/ml or less (typical RR 0.38, 95% CI 0.27 to 0.55; typical RD -0.22, 95% CI -0.29 to -0.15; NNTB = 4; 11 trials; N = 503). 'Once a day' gentamicin achieved higher peak levels (MD 2.58, 95% CI 2.26 to 2.89; 10 trials; N = 440) and lower trough levels (MD -0.57, 95% CI -0.69 to -0.44; 10 trials; N = 440) than 'multiple doses a day' regimen. There was no significant difference in ototoxicity between two groups (typical RR 1.69, 95% CI 0.18 to 16.25; typical RD 0.01, 95% CI -0.04 to 0.05; 5 trials; N = 214). Nephrotoxicity was not noted with either of the treatment regimens. Overall, the quality of evidence was considered to be moderate on GRADE analysis, given the small sample size and unclear/high risk of bias in some of the domains in a few of the included studies.

AUTHORS' CONCLUSIONS

There is insufficient evidence from the currently available RCTs to conclude whether a 'once a day' or a 'multiple doses a day' regimen of gentamicin is superior in treating proven neonatal sepsis. However, data suggest that pharmacokinetic properties of a 'once a day' gentamicin regimen are superior to a 'multiple doses a day' regimen in that it achieves higher peak levels while avoiding toxic trough levels. There was no change in nephrotoxicity or auditory toxicity. Based on the assessment of pharmacokinetics, a 'once a day regimen' may be superior in treating sepsis in neonates of more than 32 weeks' gestation.

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.

Extended interval dosing of gentamicin in premature neonates ≤ 28-week gestation

AIM

To evaluate an extended interval dosing (EID) regimen of gentamicin in neonates ≤28-week gestation.

METHODS

In 2008, an EID regimen for gentamicin was introduced for all neonates admitted to the NICU in Calgary. The dosing interval was based on a 22 h level after the first dose of 5mg/kg. We conducted an observational study in 33 infants ≤28-week gestation on the EID regimen from the first day of life and compared gentamicin peak and trough levels with a historical control of 34 infants who received gentamicin in a dose of 2.5 mg/kg every 24 h (TID, traditional interval dosing).

RESULTS

In the EID group, based on the 22 h level, dosing interval was 36 h in 20 neonates and 48 h in 13 neonates. All neonates, except one, achieved therapeutic peak and trough levels. Compared to the TID group, the EID group had higher peak levels (median 9.8 μg/mL vs. 4.6 μg/mL, p < 0.001) with no difference in trough levels. With target peak levels of 5-12 μg/mL and trough levels of <2 μg/mL, a higher proportion of neonates in the TID group would need dose adjustment.

CONCLUSION

In neonates ≤ 28-week gestation, an EID regimen from day one of life, using a single level 22 h after the first dose for dosing interval, achieves therapeutic peak and trough levels and more optimum peak levels as compared to a TID regimen.

One dose per day compared to multiple doses per day of gentamicin for treatment of suspected or proven sepsis in neonates

BACKGROUND

Animal studies and trials in older children and adults suggest that a one dose per day regimen of gentamicin is superior to a multiple doses per day regimen.

OBJECTIVES

To compare the efficacy and safety of one dose per day compared to multiple doses per day of gentamicin in suspected or proven sepsis in neonates.

SEARCH METHODS

Eligible studies were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, April 2011), MEDLINE (1966 to April 2011), EMBASE 1980 to April 2011, and CINAHL (December 1982 to April 2011). Abstracts of the Society for Pediatric Research were searched from 1980 to 2010 inclusive.

SELECTION CRITERIA

All randomised or quasi randomised controlled trials comparing one dose per day ( 'once a day') compared to multiple doses per day ( 'multiple doses a day') of gentamicin to newborn infants < 28 days of life.

DATA COLLECTION AND ANALYSIS

Data collection and analysis was performed according to the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

Eleven studies were included (N = 574) and nineteen excluded. All infants in both 'once a day' as well as 'multiple doses a day' regimen showed adequate clearance of sepsis [typical RD 0.00 (95% CI - 0.19 to 0.19); 3 trials; N = 36]. For the other primary outcome measures relating to gentamicin pharmacokinetics 'once a day' dosing of gentamicin was superior. 'Once a day' gentamicin regimen was associated with less failures to attain peak level of at least 5 µg/ml [typical RR 0.22 (95% CI 0.11 to 0.47); 9 trials; N = 422] and less failures to achieve trough levels of < 2 µg/ml [typical RR 0.38 (95% CI 0.27 to 0.55); 11 trials N = 503] compared to 'multiple doses a day' regimen.Ototoxicity and nephrotoxicity were not noted with either of the treatment regimens.

AUTHORS' CONCLUSIONS

There is insufficient evidence from the currently available RCTs to conclude whether 'once a day' or 'multiple doses a day' regimen of gentamicin is superior in treating proven neonatal sepsis. However, data suggests that pharmacokinetic properties of 'once a day' gentamicin regimen are superior to 'multiple doses a day' regimen in that it achieves higher peak levels while avoiding toxic trough levels. There is no change in nephrotoxicity or auditory toxicity. Based on this assessment of pharmacokinetics, 'once a day regimen' may be superior in treating neonatal sepsis in neonates greater than 32 weeks gestation.

Aminoglycoside trough levels in neonates

Introduction. Drug safety depends on trough levels. Objective. Objective of the study was to measure gentamicin and amikacin trough levels in neonates and to identify risk groups by gestational and postnatal age. Methods. Gentamicin and amikacin were applied according to the clinical practice guidelines. Trough levels (mg/l) were deter- mined using fluorescence polarization immunoassay methodology. Target trough levels were <2 mg/l for gentamicin, and <10 mg/l for amikacin. Patients were divided in 3 groups by gestational age: I ?32, II 33-36, and III ?37 gestational weeks and, by postnatal age, in 2 groups: ?7 and >7 days. Results. Out of 163 neonates, 111 were receiving gentamicin and 52 amikacin. Mean amikacin trough level was 7.8?4.8 mg/l and, in group I 10.5?4.9 mg/l, which was above the target range and significantly higher than in group II (LSD, p<0.05). In the amikacin group, 26 patients were 7 and less, and 26 more than 7 days old, without significant differences in trough levels between the groups. In the gentamicin group, 52.3% of neonates had trough values within the target range. Gentamicin trough level in group I was above the trough range, 3.7?1.8, 2.3?1.5 in group II and, 1.8?1.4 mg/l in group III. The difference in trough levels among the groups was highly significant (F=9.015, p<0.001, ?2=17. 576, p<0.001). Further analysis revealed that differences between groups I and II (LSD, p=0.002) and between I and III (LSD, p=0.000) were highly significant. Conclusion. Obtained gentamicin and amikacin trough levels are high. Inverse correlation has been confirmed between trough level and gestational age, with highly significant difference, and the risk group has been identified. There is obviously a need to change the dosing regimen in terms of those with extended intervals, particularly for neonates of the lowest gestational age, along with pharmacokinetic measurements.

[Comparison of two gentamicin dosing schedules in the newborn]

INTRODUCTION

Gentamicin is widely used in full-term neonates as empirical therapy for early-onset suspected or proven sepsis. Several dosing schedules for gentamicin have been recommended for this neonatal population.

OBJECTIVE

To compare gentamicin serum levels, efficacy and toxicity of two dosing schedules in term and preterm newborns.

MATERIAL AND METHODS

The study included 200 newborns who were started on gentamicin therapy. Group A (N=100) was prescribed a multiple-daily dosing regimen and Group B (N=100) on a once-daily dosing regimen. Newborns in Group A received gentamicin at 2.5-3.5 mg/kg/dose q12-18 h depending on postnatal age and serum creatinine levels, and newborns in Group B received 4-5 mg/kg/dose q24-48 h depending on postconceptional and postnatal age. All peak and trough serum drug levels, demographic data, and markers of potential nephrotoxicity and ototoxicity were compared.

RESULTS

Peak serum gentamicin levels were significantly higher (8.2+/-0.22 microg/ml vs. 5.9+/-0.13 microg/ml; p <or= 0.001) and trough levels were significantly lower (0.9+/-0.06 microg/ml vs. 1.7+/-0.08 microg/ml; p <or= 0.001) in Group B than in Group A. There was no significant difference between the groups either in the clinical failure rate or in the nephrotoxicity or ototoxicity outcomes.

CONCLUSIONS

Once-daily dosing regimen of gentamicin in preterm and term newborns is safe and effective, with a reduced risk of serum drug concentrations falling outside the therapeutic range.

Vestibular system in infants after systemic aminoglycoside therapy

OBJECTIVES

The ototoxic action of systemic therapy with aminoglycoside antibiotics leading to the loss of inner ear hair cells is well recognized. The mitochondria-mediated pathway of apoptosis may play a role in inducing the apoptosis of vestibular hair cells due to aminoglycoside toxicity. Aminoglycosides are, nevertheless, routinely used for treatment of vital infections in neonatologic departments. Although there is a strong supposition that aminoglycosides can influence the vestibular function in infants, the routine examination of the infants' inner ear does not include vestibular tests. The purpose of the present study was to evaluate vestibular function in a group of infants prior to and after administration of systemic aminoglycosides, using caloric tests and vestibular-evoked myogenic potentials (VEMPs).

METHODS

VEMPs and auditory brainstem responses were recorded and caloric stimulation was performed in 68 infants aged 2.5-3.5 months: 40 healthy controls and 28 infants after therapy with amikacin, 15mg/(kgday) in three doses. The therapy duration varied from 10 to 14 days. In 18 infants antibiotic therapy was administered for a respiratory infection, and in 10 for sepsis. Infants with other risk factors of inner ear damage and treated with more than one ototoxic drug were excluded from the study. The tests were performed on the day of admission to hospital and repeated on the day of discharge.

RESULTS

The results of all tests were normal on admission. On the day of discharge, no reaction to caloric stimulation was elicited in six patients and no VEMPs were recorded in four subjects. Hearing thresholds were normal in all the individuals during both examinations.

CONCLUSIONS

The vestibular organ in infants after systemic therapy with amikacin may be damaged more frequently than the cochlear organ. The horizontal canal is more vulnerable to aminoglycosides, as compared to the saccule. The vestibular organ should be routinely examined in infants after systemic treatment with aminoglycosides.

Acute effects of gentamicin on glomerular and tubular functions in preterm neonates

It has been reported that gentamicin causes natriuresis, magnesuria and calciuria in neonates. The aim of this study was to determine the acute effects of trough and peak levels of gentamicin on the values of serum creatinine (SCr), urine albumin/urine creatinine (UA/UCr), fractional excretion of sodium and potassium (FENa, FEK) and urine calcium/urine creatinine (UCa/UCr) in preterm neonates treated with gentamicin for suspected infection. Baseline levels of serum and urine Cr, Na and K and urine albumin and Ca levels together with trough and peak gentamicin levels were measured in 61 preterm neonates at the start of the therapy, on the day of the third gentamicin dose and 48-72 h after the cessation of the gentamicin therapy. Therapeutic trough and peak levels were recorded in 56 (91.8%) and 39 (63.9%) of the preterm neonates, respectively, whereas high trough (>2 mg/dl) and peak (>9.99 mg/dl) levels were recorded in five (8.1%) and 11 (18%) of the 61 preterm neonates, respectively. Trough and peak levels of gentamicin were positively correlated with SCr, UA/UCr, FENa, FEK and UCa/UCr values. The UA/UCr, FENa and UCa/UCr values recorded during treatment were statistically significantly different from sub-therapeutic, therapeutic and high peak gentamicin levels. Gentamicin was found to have a serum peak level-dependent microalbuminuric, natriuric and calciuric effect in preterm neonates. Based on these results, we suggest that when the monitoring of serum gentamicin levels is not possible, the monitoring of UA/UCr, FENa and UCa/UCr can be useful as a noninvasive alternative.

One dose per day compared to multiple doses per day of gentamicin for treatment of suspected or proven sepsis in neonates

BACKGROUND

Gentamicin is widely used in the treatment of suspected or proven neonatal sepsis. Animal studies and systematic reviews from trials in older children and adults suggest that a one dose per day regimen is superior to a multiple doses per day regimen. Pharmacokinetic studies and retrospective audits in neonatal population also favour once a day administration of gentamicin. However, there is no consensus regarding the dose interval regimen in the neonatal population.

OBJECTIVES

To compare the efficacy and safety of one dose per day compared to multiple doses per day of gentamicin in suspected or proven sepsis in neonates.

SEARCH STRATEGY

Eligible studies were identified by searching MEDLINE (March 2005), EMBASE 1980 - 2004, Oxford Database of Perinatal Trials, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2005) and CINAHL (December 1982 - March 2005). Abstracts of the Society for Pediatric Research were hand searched from 1980 to 2004 inclusive. No language restrictions were applied.

SELECTION CRITERIA

All randomised or quasi randomised controlled trials comparing one dose per day ( 'once a day') compared to multiple doses per day ( 'multiple doses a day') of gentamicin to newborn infants < 28 days of life.

DATA COLLECTION AND ANALYSIS

Methodological quality of eligible studies was assessed according to allocation concealment, blinding of intervention, blinding of outcome assessment and completeness of follow up. Data were sought regarding effects on clinical efficacy, pharmacokinetic efficacy, ototoxicity and nephrotoxicity of the two regimens. When appropriate, meta-analysis was conducted to provide a pooled estimate of effect. For categorical data, the typical relative risk (RR), typical risk difference (RD) and number needed to treat (NNT) with 95% confidence intervals (CI) were calculated. Continuous data were analysed using weighted mean difference (WMD).

MAIN RESULTS

Twenty four studies were initially identified. Thirteen were excluded and eleven studies (N = 574) included. All studies compared the effectiveness and safety of 'once a day' versus 'multiple doses a day' regimen of gentamicin in newborn infants. Only one study enrolled infants less than 32 weeks gestation. All except one trial used intravenous infusion. One trial used gentamicin as a bolus dose over one minute. Two trials used intramuscular gentamicin in some of their study infants. For the primary outcome of 'clearance of sepsis', all infants in both 'once a day' as well as 'multiple doses a day' regimen showed adequate clearance of sepsis [Typical RD 0.00 (95% CI - 0.19, 0.19); 3 trials; N = 36]. For the other primary outcome measures relating to gentamicin pharmacokinetics, 'once a day dosing' of gentamicin was superior. 'Once a day' gentamicin regimen is associated with less failures to attain peak level of at least 5 microg/ml [Typical RR 0.22 (95% CI 0.11, 0.47); Typical RD -0.13 (95% CI -0.19, -0.08); 9 trials; N = 422]; less failures to achieve trough levels of < 2 microg/ml [Typical RR 0.38 (95% CI 0.27, 0.55); Typical RD -0.22 (95% CI -0.29, -0.15); 11 trials N = 503]; higher peak levels [WMD 2.58 (95% CI 2.26, 2.89); 10 trials; N = 440] and lower trough levels [WMD -0.57 (95% CI -0.69, -0.44); 10 trials; N = 440] compared to 'multiple doses a day' regimen. Ototoxicity and nephrotoxicity were not noted with either of the treatment regimens. Significant heterogeneity was noted for some of the outcomes measured. Hence the results need to be interpreted with caution. Possible reasons for heterogeneity are different gestational ages of study infants and the timing of collection of blood samples in relation to a particular dose and the day of therapy on which the samples were collected.

AUTHORS' CONCLUSIONS

There is insufficient evidence from the currently available RCTs to conclude whether 'once a day' or 'multiple doses a day' regimen of gentamicin is superior in treating proven neonatal sepsis. However data suggests that pharmacokinetic properties of 'once a day' gentamicin regimen are superior to 'multiple doses a day' regimen in that it achieves higher peak levels while avoiding toxic trough levels. There is no change in nephrotoxicity or auditory toxicity. Based on this assessment of pharmacokinetics, 'once a day regimen' may be superior in treating neonatal sepsis in neonates more than 32 weeks gestation.