Comparison of 5 milligrams of netilmicin per kilogram of body weight once daily versus 2 milligrams per kilogram thrice daily for treatment of gram-negative pyelonephritis in children

Antibiotics and Cure Rates in Childhood Febrile Urinary Tract Infections in Clinical Trials: A Systematic Review and Meta-analysis

PURPOSE

Urinary tract infections (UTIs) are common bacterial infections among children.

OBJECTIVE

To systematically review the antimicrobials used for febrile UTIs in paediatric clinical trials and meta-analyse the observed cure rates and reasons for treatment failure.

MATERIALS AND METHODS

We searched Medline, Embase and Cochrane central databases between January 1, 1990, and November 24, 2016, combining MeSH and free-text terms for: "urinary tract infections", AND "therapeutics", AND "clinical trials" in children (age range 0-18 years). Two independent reviewers assessed study quality and performed data extraction. The major outcome measures were clinical and microbiological cure rates according to different antibiotics.

RESULTS

We identified 2762 published studies and included 30 clinical trials investigating 3913 cases of paediatric febrile urinary tract infections. Children with no underlying condition were the main population included in the trials (n = 2602; 66.5%). Cephalosporins were the most frequent antibiotics studied in trials (22/30, 73.3%). Only a few antibiotics active against resistant UTIs have been tested in randomised clinical trials, mainly aminoglycosides. The average point cure rate of all investigational drugs was estimated to 95.3% (95% CI 93.5-96.9%). Among 3002 patients for whom cure and failure rates were reported, only 3.9% (3.9%; 118/3002) were considered clinically to have treatment failure, while 135 (4.5%; 135/3002) had microbiological failure.

CONCLUSIONS

We observed high treatment cure rates, regardless of the investigational drug chosen, the route of administration, duration and dosing. This suggests that future research should prioritise observational studies and clinical trials on children with multi-drug-resistant infections.

Urinary Tract Infection Antibiotic Trial Study Design: A Systematic Review

CONTEXT

Urinary tract infections (UTIs) represent common bacterial infections in children. No guidance on the conduct of pediatric febrile UTI clinical trials (CTs) exist.

OBJECTIVE

To assess the criteria used for patient selection and the efficacy end points in febrile pediatric UTI CTs.

DATA SOURCES

Medline, Embase, Cochrane central databases, and clinicaltrials.gov were searched between January 1, 1990, and November 24, 2016.

STUDY SELECTION

We combined Medical Subject Headings terms and free-text terms for "urinary tract infections" and "therapeutics" and "clinical trials" in children (0-18 years), identifying 3086 articles.

DATA EXTRACTION

Two independent reviewers assessed study quality and performed data extraction.

RESULTS

We included 40 CTs in which a total of 4381 cases of pediatric UTIs were investigated. Positive urine culture results and fever were the most common inclusion criteria (93% and 78%, respectively). Urine sampling method, pyuria, and colony thresholds were highly variable. Clinical and microbiological end points were assessed in 88% and 93% of the studies, respectively. Timing for end point assessment was highly variable, and only 3 studies (17%) out of the 18 performed after the Food and Drug Administration 1998 guidance publication assessed primary and secondary end points consistently with this guidance.

LIMITATIONS

Our limitations included a mixed population of healthy children and children with an underlying condition. In 6 trials, researchers studied a subgroup of patients with afebrile UTI.

CONCLUSIONS

We observed a wide variability in the microbiological inclusion criteria and the timing for end point assessment. The available guidance for adults appear not to be used by pediatricians and do not seem applicable to the childhood UTI. A harmonized design for pediatric UTIs CT is necessary.

Once-Daily Aminoglycosides: A Meta-Analysis of Nonneutropenic and Neutropenic Adults

Objective:

To compare the efficacy, nephrotoxicity, and ototoxicity of once-daily dosing of aminoglycosides versus conventional dosing.

Design:

Meta-analysis of 14 randomized trials identified through a MEDLINE search (January 1965-May 1996).

Patients:

Neutropenic and nonneutropenic adults.

Interventions:

Patients were randomly selected to receive an aminoglycoside once daily or in multiple daily doses.

Measurements and Main Outcomes:

The outcomes considered were clinical cure, bacteriologic cure, nephrotoxicity, auditory toxicity, and vestibular toxicity. The data were analyzed in the following subgroups: (1) all trials, (2) nonneutropenic patients, (3) neutropenic patients, and (4) patients with undefined neutrophil status. For all trials the pooled risk ratio was 1.268 (95% CI 0.828 to 1.939) for clinical cure, and was 1.390 (95% CI 1.350 to 1.392) for bacteriologic cure. Nephrotoxicity had a pooled risk ratio of 0.765 (95% CI 0.468 to 1.252), that for auditory toxicity was 1.117 (95% CI 0.151 to 5.636), and that for vestibular toxicity was 1.155 (95% CI 0.221 to 6.039). Analysis of the subgroups, including a separate analysis of neutropenic patients, demonstrated similar results.

Conclusions:

When all trials were considered, once-daily administration of aminoglycosides had similar efficacy and no increase in nephrotoxicity or ototoxicity compared with conventional aminoglycoside dosing.

Antibiotics for acute pyelonephritis in children

BACKGROUND

Urinary tract infection (UTI) is one of the most common bacterial infections in infants. The most severe form of UTI is acute pyelonephritis, which results in significant acute morbidity and may cause permanent kidney damage. There remains uncertainty regarding the optimum antibiotic regimen, route of administration and duration of treatment. This is an update of a review that was first published in 2003 and updated in 2005 and 2007.

OBJECTIVES

To evaluate the benefits and harms of antibiotics used to treat children with acute pyelonephritis. The aspects of therapy considered were 1) different antibiotics, 2) different dosing regimens of the same antibiotic, 3) different duration of treatment, and 4) different routes of administration.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register, CENTRAL, MEDLINE, EMBASE, reference lists of articles and conference proceedings without language restriction to 10 April 2014.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing different antibiotic agents, routes, frequencies or durations of therapy in children aged 0 to 18 years with proven UTI and acute pyelonephritis were selected.

DATA COLLECTION AND ANALYSIS

Four authors independently assessed study quality and extracted data. Statistical analyses were performed using the random-effects model and the results expressed as risk ratio (RR) for dichotomous outcomes or mean difference (MD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

This updated review included 27 studies (4452 children). This update included evidence from three new studies, and following re-evaluation, a previously excluded study was included because it now met our inclusion criteria.Risk of bias was assessed as low for sequence generation (12 studies), allocation concealment (six studies), blinding of outcome assessors (17 studies), incomplete outcome reporting (19 studies) and selective outcome reporting (13 studies). No study was blinded for participants or investigators. The 27 included studies evaluated 12 different comparisons. No significant differences were found in duration of fever (2 studies, 808 children: MD 2.05 hours, 95% CI -0.84 to 4.94), persistent UTI at 72 hours after commencing therapy (2 studies, 542 children: RR 1.10, 95% CI 0.07 to 17.41) or persistent kidney damage at six to 12 months (4 studies, 943 children: RR 0.82, 95% CI 0.59 to 1.12) between oral antibiotic therapy (10 to 14 days) and intravenous (IV) therapy (3 days) followed by oral therapy (10 days). Similarly, no significant differences in persistent bacteriuria at the end of treatment (4 studies, 305 children: RR 0.78, 95% CI 0.24 to 2.55) or persistent kidney damage (4 studies, 726 children: RR 1.01, 95% CI 0.80 to 1.29) were found between IV therapy (three to four days) followed by oral therapy and IV therapy (seven to 14 days). No significant differences in efficacy were found between daily and thrice daily administration of aminoglycosides (1 study, 179 children, persistent clinical symptoms at three days: RR 1.98, 95% CI 0.37 to 10.53). Adverse events were mild and uncommon and rarely resulted in discontinuation of treatment.

AUTHORS' CONCLUSIONS

This updated review increases the body of evidence that oral antibiotics alone are as effective as a short course (three to four days) of IV antibiotics followed by oral therapy for a total treatment duration of 10 to 14 days for the treatment of acute pyelonephritis in children. When IV antibiotics are given, a short course (two to four days) of IV therapy followed by oral therapy is as effective as a longer course (seven to 10 days) of IV therapy. If IV therapy with aminoglycosides is chosen, single daily dosing is safe and effective. Insufficient data are available to extrapolate these findings to children aged less than one month of age or to children with dilating vesicoureteric reflux (grades III-V). Further studies are required to determine the optimal total duration of antibiotic therapy required for acute pyelonephritis.

Once-daily gentamicin in infants and children: a prospective cohort study evaluating safety and the role of therapeutic drug monitoring in minimizing toxicity

BACKGROUND

The clinical evidence base for ototoxicity and nephrotoxicity outcomes with once-daily dosing (ODD) of gentamicin in children is suboptimal. Therapeutic drug monitoring (TDM) in once-daily gentamicin regimens is variable and its role in predicting or preventing clinical toxicity is unclear. We aimed to assess the safety of ODD of gentamicin and the usefulness of TDM in a pediatric cohort.

METHODS

Children with suspected sepsis were prospectively enrolled to receive ODD of gentamicin at 7 mg/kg/day. Hearing and renal function were objectively assessed at baseline, during therapy, and after therapy. TDM was performed using an interval-adjusted graphical method (Hartford nomogram).

RESULTS

A total of 79 children (median age: 5.6 years; range: 1 month-16 years) received 106 episodes of therapy. In all, 61% of these episodes were for febrile neutropenia. Evaluation was complete in 88% for ototoxicity and 92% for nephrotoxicity. Two patients (1.88%, 95% confidence interval: 0.10%-7.13%) experienced permanent hearing loss. One patient (0.94%, 95% confidence interval: <0.10%-5.73%) experienced transient nephrotoxicity. No abnormal serum gentamicin values were detected, even in those experiencing toxicity. Children experiencing toxicity were undergoing treatment for malignancies and had received nephrotoxic or ototoxic medicines before gentamicin.

CONCLUSIONS

In this pediatric cohort receiving ODD of gentamicin, nephrotoxicity was uncommon and reversible, but irreversible ototoxicity occurred more frequently. TDM using a nomogram neither predicted nor prevented toxicity, which was only observed in those with risk factors.

Antibiotics for acute pyelonephritis in children

BACKGROUND

Urinary tract infection (UTI) is one of the most common bacterial infection in infants. The most severe form of UTI is acute pyelonephritis, which results in significant acute morbidity and may cause permanent renal damage. Published guidelines recommend treatment of acute pyelonephritis initially with intravenous (IV) therapy followed by oral therapy for seven to 14 days though there is no consensus on the duration of either IV or oral therapy.

OBJECTIVES

To determine the benefits and harms of different antibiotic regimens for the treatment of acute pyelonephritis in children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, reference lists of articles and conference proceedings without language restriction. Date of most recent search: December 2006.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing different antibiotic agents, routes, frequencies or durations of therapy in children aged 0 to 18 years with proven UTI and acute pyelonephritis were selected.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) for dichotomous outcomes or mean difference (WMD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

Twenty three studies (3295 children) were eligible for inclusion. No significant differences were found in persistent renal damage at 6 months (2 studies, 424 children: RR 0.87, 95% CI 0.35 to 2.16) or in duration of fever (2 studies, 693 children: WMD 1.54, 95% CI -1.67 to 4.76) between oral antibiotic therapy (10 to 14 days) and IV therapy (3 days) followed by oral therapy (10 days). Similarly no significant differences in persistent renal damage (3 studies, 341 children: RR 1.13, 95% CI 0.86 to 1.49) were found between IV therapy (3 to 4 days) followed by oral therapy and IV therapy for 7 to 14 days. No significant differences in efficacy were found between daily and thrice daily administration of aminoglycosides (1 study, 179 children, persistent symptoms at 3 days: RR 1.98, 95% CI 0.37 to 10.53).

AUTHORS' CONCLUSIONS

These results suggest that children with acute pyelonephritis can be treated effectively with oral antibiotics (cefixime, ceftibuten and amoxycillin/clavulanic acid) or with short courses (2 to 4 days) of IV therapy followed by oral therapy. If IV therapy is chosen, single daily dosing with aminoglycosides is safe and effective. Studies are required to determine the optimal total duration of therapy.

Prise en charge des pyélonéphrites aiguës du nourrisson de plus de 3 mois et de l'enfant : enquête effectuée parmi les services d'urgences pédiatriques d'Île de France en 2004

OBJECTIVES

To describe the different modalities of ambulatory management of acute pyelonephritis in patients older than 3 months of age in paediatric emergency units of the Ile de France region in 2004.

METHODS

Between October 2003 and April 2004, referents of 39 paediatric emergency units of the Ile de France region were questioned through a written questionnaire concerning the management of acute pyelonephritis: in or outpatient modalities, antibiotic regimen (molecule and route of administration), investigations and follow-up.

RESULTS

Thirty-one questionnaires (79.5%) were returned and analysed. A written protocol was available in 60% of the units. Outpatient management was performed in 24/31 centres. Young age, poor clinical tolerance, urological abnormalities and social difficulties were the major contra-indications for such management. Ultrasonic echography at diagnosis (within 24 h) was performed in 50% of the units. Antibiotics were started using IV route in 18/24 units (75%) and ceftriaxone and aminoside were respectively prescribed in 100% and 29.4% of the units for a duration of 1 to 5 days before switching to the oral route. Antibiotherapy was started orally in 6 units and cefixime was chosen by 5 of them. Follow-up consultations were scheduled in 100% of the units but with various delay after initiation of the treatment. The total duration of treatment was mostly 10 days and oral prophylactic antibiotherapy was prescribed by 10/24 centres after completion of the treatment. Cystoureterography was systematically realized by 83.3% of the units.

CONCLUSIONS

Despite important differences in the management of acute pyelonephritis in Ile-de-France, a majority of the units follows similar therapeutic modalities. In the absence of consensus, new recommendations are necessary concerning the management of pyelonephritis in infants and children in France.

Once-daily netilmicin for neutropenic pyrexia in paediatric oncology

AIM

To establish the safety and efficacy of single daily intravenous netilmicin 6 mg/kg with piperacillin 100 mg/kg every 8 h for empirical, first-line management of children with neutropenic pyrexia following cytotoxic chemotherapy.

METHODS

Observational study of children admitted to a regional oncology unit from October 1999-April 2002. Primary outcome measure was temperature 72 h after commencing antibiotic therapy; secondary measures were mortality, nephrotoxicity, symptomatic ototoxicity and serum netilmicin levels.

RESULTS

280 episodes for 128 patients (median age 7.1 y) were documented, and 248 episodes were evaluated and compared with a previous cohort of 100 episodes for which the only difference was administration of netilmicin three times daily. Twenty-seven per cent of single-dose netilmicin episodes remained febrile at 72 h compared to 32% in the comparator group (difference -4.7%; 95 % CI: -6.8% to 16.2%; p = 0.41). No patients died and we were unable to find evidence of nephrotoxicity or ototoxicity. Eighty-nine per cent of "peak" serum netilmicin levels measured 30 min after infusion were 10 mg/l or greater, and 94% and 86% measured 12-16 h after the first and third dose, respectively, were 1 mg/l or less. Peak serum netilmicin level measurements and 12-16-h measurements after the first dose were abandoned after the first 180 episodes.

CONCLUSIONS

Netilmicin can safely be given as a single daily dose to children with febrile neutropenia who do not have biochemical evidence of nephrotoxicity. Monitoring peak serum levels of netilmicin is unnecessary. Levels taken 12-16 h after the third dose are adequate to monitor therapy if used in conjunction with a therapeutic guideline detailing the response to abnormal serum creatinine and netilmicin levels.

Antibiotics for acute pyelonephritis in children

BACKGROUND

Urinary tract infection (UTI) is one of the most common bacterial infection in infants. The most severe form of UTI is acute pyelonephritis, which results in significant acute morbidity and may cause permanent renal damage. Published guidelines recommend treatment of acute pyelonephritis initially with intravenous (IV) therapy followed by oral therapy for seven to 14 days though there is no consensus on the duration of either IV or oral therapy.

OBJECTIVES

To determine the benefits and harms of different antibiotic regimens for the treatment of acute pyelonephritis in children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, reference lists of articles and abstracts from conference proceedings without language restriction. Date of most recent search: June 2004.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing different antibiotic agents, routes, frequencies or durations of therapy in children aged 0 to 18 years with proven UTI and acute pyelonephritis were selected.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) for dichotomous outcomes or weight mean difference (WMD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

Eighteen trials (2612 children) were eligible for inclusion. No significant differences were found in persistent renal damage at six months (one trial, 306 infants: RR 1.45, 95% CI 0.69 to 3.03) or in duration of fever (WMD 0.80, 95% CI -4.41 to - 6.01) between oral cefixime therapy (14 days) and IV therapy (three days) followed by oral therapy (10 days). Similarly no significant differences in persistent renal damage (three trials, 315 children: RR 0.99, 95% CI 0.72 to 1.37) were found between IV therapy (3-4 days) followed by oral therapy and IV therapy for 7-14 days. In addition no significant differences in efficacy were found between daily and thrice daily administration of aminoglycosides (one trial, 179 children, persistent symptoms at three days: RR 1.98, 95% CI 0.37 to 10.53).

AUTHORS' CONCLUSIONS

These results suggest that children with acute pyelonephritis can be treated effectively with oral cefixime or with short courses (2-4 days) of IV therapy followed by oral therapy. If IV therapy is chosen, single daily dosing with aminoglycosides is safe and effective. Trials are required to determine the optimal total duration of therapy and if other oral antibiotics can be used in the initial treatment of acute pyelonephritis.

Treatment of urinary tract infections among febrile young children with daily intravenous antibiotic therapy at a day treatment center

OBJECTIVE

Urinary tract infections (UTIs) are common among infants and toddlers. Children can be treated effectively with short courses (2-4 days) of intravenous (IV) therapy followed by oral therapy. If IV therapy is chosen, use of once-daily dosing may allow outpatient management instead of hospital admission. However, no description of ambulatory treatment with IV antibiotics of UTI among febrile children has been reported to date. We aimed to describe the feasibility and complications of outpatient management with IV antibiotics of UTI among febrile children, at the day treatment center (DTC) of a tertiary-care pediatric hospital.

METHODS

Between April 1, 2002, and March 31, 2003, a prospective cohort of patients 3 months to 5 years of age who were examined in the emergency department (ED) and diagnosed as having presumed febrile UTI were treated according to a clinical protocol. Patients were treated at the DTC unless they met exclusion criteria, in which case they were hospitalized. The DTC was open 7 days per week, including holidays, from 8:30 am to 4:30 pm. At the DTC, patients were initially treated with a daily dose of IV gentamicin, until the child had been afebrile for at least 24 hours, and with oral amoxicillin, until preliminary urine culture results were available. Children allergic to penicillin received gentamicin only. IV antibiotics were administered through peripheral IV access; the IV catheter's patency was maintained with injection of 50 U of heparin once daily throughout the treatment period. Parental satisfaction with the DTC experience was assessed with an anonymous, self-administered questionnaire.

RESULTS

Two hundred ninety-one episodes of presumed febrile UTI were diagnosed in the ED, of which 212 (72.9%) were sent to the DTC. There were 71 hospital admissions (24.4%); in 9 of these instances, the child was admitted because parents refused or were unable to comply with DTC treatment. Adherence to the treatment protocol in the ED was excellent; in 92.1% of presumed febrile UTI episodes (268 of 291 episodes), the patient was referred to the appropriate setting for treatment. In 8 instances, patients who met an exclusion criterion were sent to the DTC. They should have been hospitalized, according to the protocol. At the DTC, a final diagnosis of UTI was made in 178 of the 212 episodes (84%). Patients treated at the DTC, with a final diagnosis of UTI, had a median age of 12.0 months (range: 3-68 months), and their mean initial temperature was 39.2 degrees C (SD: 1.1 degrees C). Patients were afebrile by 24 hours in 52% of UTI episodes and by 48 hours in 82%. Minor problems with IV access occurred in 9.0% of cases. The duration of IV antibiotic therapy at the DTC was 1.9 days (SD: 0.9 day). The mean number of visits to the DTC, including appointments for renal ultrasound and voiding cystourethrography evaluations, was 3.5 (SD: 0.9). Parents were present at all scheduled visits in 98.9% of cases. Four patients needed to be hospitalized from the DTC, but in only 1 case was hospital admission related to UTI treatment. Four patients with UTI treated in the DTC had positive blood cultures, 2 with Escherichia coli (both successfully treated at the DTC) and 2 with contaminants. For 4 children treated at the DTC, UTI was caused by gentamicin-resistant E coli. One patient became afebrile within 24 hours after treatment initiation with IV gentamicin; he was then treated with oral cefixime. A second patient was treated with IV ceftriaxone, administered at the DTC once culture results were available, and remained febrile for <72 hours. The last 2 patients were hospitalized; one, who was also allergic to cephalosporins, had been febrile for 72 hours at the time of hospitalization (once hospitalized, he was treated with IV amikacin), and the other was admitted to the hospital for an unrelated problem, namely, scalp cellulitis. None of these 4 patients was initially bacteremic or became bacteremic during the treatment period. Repeat urine culture was performed within 14 days after treatment initiation in 146 instances, and results were negative in all cases. At telephone follow-up assessments 14 days after discharge, no patient had been rehospitalized because of UTI. Successful treatment at the DTC (defined as attendance at all visits, normalization of temperature within 96 hours, negative control urine cultures, if performed, and absence of hospitalization from the DTC) was observed in 96.6% of the 178 UTI episodes. Overall adherence of physicians to the protocol at the DTC was 87.1% (95% confidence interval: 82.2-92.0%). One hundred seventy-two satisfaction questionnaires were returned and revealed good, very good, or excellent parental satisfaction in 98.8% of cases.

CONCLUSIONS

Our data show that ambulatory treatment with IV antibiotics, at a DTC, may be used for at least three-fourths of UTIs among febrile children 3 months to 5 years of age. It is safe and feasible and appears very satisfactory to parents. Although ambulatory treatment with IV antibiotics is more invasive than oral therapy during the initiation of UTI treatment, it ensures almost full compliance, allows close medical supervision, and facilitates investigations related to the UTI. It is an interesting alternative to hospitalization.

Extended-interval aminoglycoside administration for children: a meta-analysis

BACKGROUND

There has been a long-standing debate regarding whether aminoglycosides should be administered on a multiple daily dosing (MDD) or once-daily dosing (ODD) schedule. Several unique characteristics of the aminoglycosides make ODD an attractive and possibly superior alternative to MDD. These include concentration-dependent bactericidal activity; postantibiotic effect, which allows continued efficacy even when serum concentrations fall below expected minimum inhibitory concentrations; decreased risk of adaptive resistance; and diminished accumulation in renal tubules and inner ear.

OBJECTIVE

To assess the relative efficacy and toxicity of ODD, compared with MDD, of aminoglycosides among pediatric patients.

STUDY SELECTION

Randomized, controlled trials among children, evaluating the relative efficacy and toxicity of ODD versus MDD of aminoglycosides, with similar total daily doses in the compared arms, were selected.

DATA SOURCES

PubMed (1966-2003) and Embase (1982-2003) databases, the Cochrane Controlled Trials Registry (2003), and references of eligible studies and pediatric review articles were searched.

DATA EXTRACTION

Study population characteristics and outcome data were extracted independently in duplicate, and consensus was reached on all items. The following outcome data were considered: (1) clinical or microbiologic failure, as defined in each study; (2) clinical failure; (3) microbiologic failure; (4) primary nephrotoxicity, ie, any rise in serum creatinine or decrease in creatinine clearance with thresholds as defined in each study; (5) secondary nephrotoxicity, ie, urinary excretion of proteins or phospholipids; and (6) ototoxicity based on pure tone audiometry, brainstem auditory evoked responses, or otoacoustic emissions for neonates and infants, vestibular testing, clinical impression, or any other method. All of the efficacy and toxicity outcomes were evaluated at the end of therapy.

RESULTS

Identification of eligible studies and study characteristics: 24 eligible studies published between 1991 and 2003 were identified. Aminoglycosides were used in different clinical settings (neonatal intensive care unit: 6 studies; cystic fibrosis: 3 studies; cancer: 5 studies; urinary tract infections: 4 studies; diverse infectious indications: 5 studies; pediatric intensive care unit: 1 study). Aminoglycosides used included amikacin (9 studies), gentamicin (11 studies), tobramycin (2 studies), netilmicin (2 studies), and tobramycin or netilmicin (1 study).

EFFICACY

There was no significant difference between ODD and MDD in the clinical failure rate, microbiologic failure rate, and combined clinical or microbiologic failure rates, but trends favored ODD consistently. There was no between-study heterogeneity for any outcome. Efficacy analysis of all trials indicating either clinical or microbiologic failures demonstrated pooled failure rates of 4.6% (23 of 501 cases) in the ODD arms and 6.9% (34 of 494 cases) in the MDD arms. The fixed-effects risk ratio was 0.71 (95% confidence interval [CI]: 0.45-1.11). A statistically significant benefit was seen with ODD over MDD in trials using amikacin, whereas no statistical significance was seen in trials using other antibiotics. The pooled clinical failure rates were 6.7% (22 of 330 cases) in the ODD arms and 10.4% (34 of 327 cases) in the MDD arms. The fixed-effects risk ratio was 0.67 (95% CI: 0.42-1.07). The pooled microbiologic failure rates were 1.8% (5 of 283 cases) with ODD and 4.0% (11 of 275 cases) with MDD. The fixed-effects risk ratio was 0.51 (95% CI: 0.22-1.18). NEPHROTOXICITY: There was no significant difference between ODD and MDD in the primary nephrotoxicity outcomes. Secondary nephrotoxicity outcomes were significantly better with ODD. The pooled primary nephrotoxicity rates were 1.6% (15 of 955 cases) in the ODD arms and 1.6% (15 of 923 cases) in the MDD arms. The fixed-effects risk ratio was 0.97 (95% CI: 0.55-1.69). The pooled secondary nephrotoxicity rates were 4.4% (3 of 69 cases) in the ODD arms and 15.9% (11 of 69 cases) in the MDD arms, suggesting a statistically significant superiority of ODD. The fixed-effects risk ratio was 0.33 (95% CI: 0.12-0.89). Results were consistent across types of clinical settings and aminoglycosides. OTOTOXICITY: There was no significant difference between ODD and MDD in the primary ototoxicity outcomes. The pooled ototoxicity rates for studies that provided auditory testing results were 2.3% (10 of 436 cases) in the ODD arms and 2.0% (8 of 406 cases) in the MDD arms. The fixed-effects risk ratio was 1.06 (95% CI: 0.51-2.19). In studies that provided clinical vestibular function testing results, no toxicity was documented among 209 patients given ODD and 206 patients given MDD. Studies noting only the clinical impression of hearing impairment also failed to identify any toxicity (ODD: 114 cases; MDD: 114 cases). SUBGROUP AND BIAS ANALYSES: We detected no statistically significant differences between ODD and MDD in any of the examined subgroups (neonatal intensive care unit, cystic fibrosis, cancer, or urinary tract infection), with respect to combined clinical or microbiologic failure outcomes, primary nephrotoxicity outcomes, or ototoxicity (based on auditory testing), when sufficient data were available. Moreover, there was no significant relationship between the effect size (risk ratio) and the trial size for any of the outcomes. DATA INTERPRETATION: Clinical failures were uncommon in the pediatric trials, regardless of the regimen used. If anything, fewer clinical failures tended to occur with ODD. Moreover, we observed a trend toward decreased bacteriologic failures. One meta-analysis of adult data suggested that ODD might reduce nephrotoxicity, whereas other meta-analyses showed nonsignificant trends or no difference in nephrotoxicity outcomes. In our meta-analysis, we were not able to show any reduction in the risk of primary nephrotoxicity outcomes with ODD. However, the event rate was much lower among children, compared with adults, and the secondary nephrotoxicity outcomes favored ODD. Finally, although the 2 regimens seemed equivalent with respect to ototoxicity, reporting on ototoxicity outcomes was incomplete. Reassuringly, even in the trials that performed auditory testing, the rates of ototoxicity in the MDD arms were very low. These results were consistent with meta-analyses of adult data, which showed no difference in ototoxicity rates between ODD and MDD.

CONCLUSIONS

Although single trials have been small, the available randomized evidence supports the general adoption of ODD of aminoglycosides in pediatric clinical practice. This approach minimizes cost, simplifies administration, and provides similar or even potentially improved efficacy and safety, compared with MDD of these drugs.

Efficacy and tolerability of extended-interval aminoglycoside administration in pediatric patients

Aminoglycosides are commonly used to treat serious Gram-negative infections in pediatric patients. An effort to improve the efficacy and tolerability of this antibiotic class has led to evaluation of extended-interval aminoglycoside administration (EIAA). EIAA is designed to achieve higher peak plasma aminoglycoside concentrations, with relatively undetectable trough concentrations, when compared with conventional aminoglycoside administration (CAA), and is therefore expected to be markedly effective and to reduce drug accumulation and prevent nephrotoxicity and ototoxicity. Clinical trials evaluating EIAA in neonates included patients with suspected Gram-negative infections requiring short courses of aminoglycoside therapy. Consequently, comparative efficacy of EIAA versus CAA could not be assessed. In addition, ototoxicity was often not assessed, and nephrotoxicity was virtually undetectable. Similarly, trials evaluating EIAA versus CAA in infants and children have not demonstrated a difference in outcomes. The use of EIAA in children with febrile neutropenia has been evaluated primarily with amikacin. The incidences of nephrotoxicity and ototoxicity were low, and were similar between EIAA and CAA. No deaths were reported in any of these studies; however, this could be related to the inclusion of patients with undocumented bacteremia. Further investigation of EIAA is necessary in patients with documented bacteremia, since plasma aminoglycoside concentrations were undetectable for most of the dosage interval in children with febrile neutropenia who were treated once daily. Overall, clinical studies suggest that EIAA has similar efficacy to, and no higher risk of toxicity than, CAA in neonates, infants, and children. A few evaluations have also demonstrated that EIAA is cost-effective in neonates and in children with febrile neutropenia. Future studies evaluating the efficacy and tolerability of EIAA in pediatric patients with documented systemic infections should be prospective, randomized, controlled trials with sample sizes sufficient to detect differences between administration methods. Further evaluations should also address the optimal dosage and cost-effectiveness of EIAA in infants and children.

Influence of dose on the disposition kinetics of netilmicin in the isolated kidney of the rat

The disposition of Netilmicin in the isolated rat kidney was studied in order to determine the influence of dose on the drug profile in this tissue. Doses of 50, 200, 800 or 10000 mg were injected through an afferent cannula into the isolated kidney as a bolus injection and outflow perfusate samples were collected. Statistical moments (AUC, MTT, VTT) were estimated from raw outflow curve data. Unit disposition function (UDF) was obtained by mass balance for each studied dose. The results of control assays addressing the viability of the isolated kidney preparations point to a high reproducibility for this preparation under the experimental conditions used, together with an acceptable viability. Comparison of statistical moments and derived parameters such as the extraction coefficient, distribution volume and drug renal clearance (E, Vd, ClE) suggest the existence of modifications in the distribution process with the dose, while elimination seems to remain unvariable; accordingly, the unit disposition function profiles were not superimposed for the different doses but differences during the early and final phases were observed.

Randomized, controlled trial comparing once daily and three times daily gentamicin in children with urinary tract infections

OBJECTIVE

To undertake population pharmacokinetic modeling and to determine the safety and efficacy of once daily (OD) gentamicin dosing in children with severe urinary tract infections (UTI).

METHODS

An open, randomized, controlled trial comparing OD with three times daily (TD) gentamicin dosing in hospitalized children ages 1 month to 12 years with UTI. Daily doses (milligrams per kg per day) of gentamicin in both groups were 7.5 (<5 years old), 6.0 (5 to 10 years old) and 4.5 (>10 years old).

RESULTS

There were 179 children enrolled (90 OD, 89 TD). Baseline clinical characteristics and pathogens were similar, except that circulatory compromise and renal cortical scintigraphic defects were more common in the OD group. Median gentamicin treatment durations were 3.0 (OD) and 2.7 (TD) days. Mean peak gentamicin concentrations were 17.3 (OD) vs. 6.4 (TD) mg/l; 99% of peak concentrations were >7 mg/l in the OD group whereas 16% of peak concentrations were <5 mg/l in the TD group. Mean trough concentrations were 0.35 (OD) vs. 0.55 (TD) mg/l. In the OD group 4% of trough concentrations were > or = 2 mg/l, whereas in the TD group only 0.7% were > or = 2 mg/l. Age or prior elevated peak concentrations did not predict high trough concentrations. Population pharmacokinetic modeling of the data fitted a one-compartment model with first order elimination. There were no clinical or bacteriologic failures. The two disease-related complications were confined to the OD group. No nephro- or ototoxicity was identified.

CONCLUSIONS

With age-appropriate dosing and measurement of serum trough concentrations before the second dose, OD gentamicin is safe and effective for the treatment of UTI requiring parenteral treatment in children aged 1 month to 12 years.

Pharmacokinetics of single daily dose gentamicin in children with cancer

PURPOSE

To study the pharmacokinetics of single daily dose (SDD) gentamicin in children with cancer.

METHODS

Serum concentrations of gentamicin were prospectively measured at 0.5, 8, 16, and 24 hours after a single daily dose of gentamicin 6 mg/kg, given as a 30-minute infusion in 18 febrile children with cancer and a central venous catheter. Then the peak (0.5-hour) and 12-hour serum concentrations of gentamicin were prospectively measured after a SDD of 7 mg/kg during 73 febrile episodes in 54 pediatric cancer patients with suspected infections. The aim was to achieve a peak serum concentration of 15 to 20 microg/mL 10 times the minimum inhibitory concentration (MIC) for sensitive Pseudomonas strains, resulting in good bactericidal activity and a long post-antibiotic effect (PAE) after a SDD of gentamicin.

RESULTS

The mean serum peak gentamicin concentration 30 minutes after the end of the infusion of 6 mg/kg was 13.3 +/- 4.0 microg/mL. The mean serum concentration 16 hours after the infusion was 0.3 +/- 0.2 microg/mL. The mean peak and 12-hour serum concentration after SDD of 7 mg/kg was 17.2 +/- 3.9 microg/mL and 0.9 +/- 0.7 microg/mL, respectively. The mean peak serum concentration after SDD of 7 mg/kg in children younger than 5 years of age (16.1 +/- 3.5 microg/mL ) was significantly lower than that of children over 5 years of age (18.2 +/- 3.9 microg/mL; P = 0.02). The desired peak serum concentration was achieved in 67% of children younger and 84% of those older than 5 years of age.

CONCLUSION

Adequate peak serum concentrations of gentamicin in children may be obtained with a SDD of 7 mg/kg. Children younger than 5 years of age achieve lower peak serum gentamicin concentration after SDD of 7 mg/kg than those older than 5 years.

A randomized comparison of the safety and efficacy of once-daily gentamicin or thrice-daily gentamicin in combination with ticarcillin-clavulanate

PURPOSE

The primary purpose of the clinical trial was to assess the safety and efficacy of once-a-day compared with three-times-a-day gentamicin in patients with serious infections who had protocol-determined peak serum aminoglycoside concentrations.

PATIENTS AND METHODS

A total of 249 hospitalized patients with suspected or proven serious infections were randomized in a 2:2:1 ratio to gentamicin given three times a day with ticarcillin-clavulanate (TC), gentamicin once a day with TC, or ticarcillin-clavulanate (TC) alone. The gentamicin once-a-day dosage for patients with estimated creatinine clearance values of > or =80 mL/min was 5.1 mg/kg. With lower creatinine clearance estimates, the mg/kg dosage of gentamicin was decreased, and the dosage intervals (once daily or three times a day) were maintained. Evaluability required documentation of achievement of protocol-defined peak serum gentamicin levels.

RESULTS

Of the total 175 evaluable patients, there were no significant differences found between treatment regimens with respect to clinical or microbiologic efficacy. Bedside audiometry proved impractical due to the frequency of altered mental state in ill patients. Based on the traditional increase in serum creatinine values from baseline values, no differences in renal toxicity between the treatment groups was identified. When changes in renal function were reanalyzed based on maintaining, as opposed to worsening, of renal function, preservation of renal function was better in the gentamicin once-a-day patients as opposed to the gentamicin three-times-a-day patients, P <0.01.

CONCLUSIONS

Gentamicin once a day plus TC, gentamicin three times a day plus TC, and TC alone had similar effects in seriously ill hospitalized patients. The incidence of nephrotoxicity was similar in the three treatment groups. Using a nonvalidated post-hoc analysis, renal function was better preserved in gentamicin once-a-day + TC and TC-only patients as opposed to gentamicin three-times-a-day + TC.

Routine monitoring of gentamicin serum concentrations in pediatric patients with normal renal function is unnecessary

OBJECTIVE

Due to increasing demands for cost containment within the healthcare system, we evaluated the need for routine gentamicin concentrations (i.e., peak and trough with third dose).

DESIGN

Single-institution study performed concurrently with hospitalization.

SETTING

A 225-bed pediatric teaching hospital.

PARTICIPANTS

The study population consisted of 150 hospitalized pediatric patients (53% medicine, 47% surgical patients) from 3 months to 15 years old with normal serum creatinine.

OUTCOME MEASURES

If the administered dose produced diagnoses-appropriate peak concentrations of at least 4 micrograms/mL or 5 micrograms/mL in bacteremia/septicemia and at least 6 micrograms/mL or 8 micrograms/mL in patients with pneumonia if trough serum gentamicin concentrations were less than 2 micrograms/mL, if the patient was noted by the attending physician to be clinically responding as well as objectively having a decreased white blood cell count and was afebrile, and if there was not an increase of 0.5 mg/dL or more in serum creatinine during the course of therapy.

RESULTS

Patients received a mean dose of gentamicin 2.51 +/- 0.14 mg/kg i.v. q8h, which resulted in a mean peak concentration of 6.1 +/- 1.7 micrograms/mL (range 2.4-11.7) and a mean trough concentration of 0.5 +/- 0.3 microgram/mL (range 0.1-1.8). Peak and trough concentrations were at least 4 micrograms/mL and less than 2 micrograms/mL in 96% and 100% of patients, respectively. No patient required a dosage change due to lack of clinical response.

CONCLUSIONS

Our data do not support the routine monitoring of gentamicin concentrations in pediatric patients older than 3 months of age who are receiving appropriate standard doses of gentamicin and have normal renal function.

A comparison of two amikacin dosing regimens in paediatric surgical patients

This investigation aimed to compare the efficacy and toxicity of two amikacin dosing regimens in seriously ill paediatric surgical patients. Children (0.6-12 years old) received amikacin intravenously either once daily (15 mg/kg, n = 27) or twice daily (7.5 mg/kg, n = 27). Concomitant medication was given as prescribed. Mean (SD) peak serum amikacin levels were significantly different (p < 0.05) between the once and twice daily groups (37.7 (6.9) mg/l and 19.5 (3.7) mg/l, respectively). Cumulative dose and duration of therapy were also significantly higher in the once-daily group. Regimen efficacy (favourable, unfavourable or indeterminate outcome) was assessed by patient temperatures, clinical improvement and white cell counts. Serum creatinine measurements and post-therapy, pure tone air conduction audiometry assessed nephro- and ototoxicity, respectively. No statistically significant differences were found between the groups in terms of outcome (18/24 and 22/25 patients in the once- and twice-daily groups had favourable outcomes; there were no unfavourable outcomes), nephrotoxicity (none of the patients assessed developed nephrotoxicity) or ototoxicity (2/20 and 5/20 patients, respectively, had mild high frequency hearing deficits which were predominantly unilateral and reversible). Although the regimens were similar in this study, other investigations will further clarify the optimal dosing approach in paediatric patients.

Rational prescribing of antibacterials in ambulatory children

The rational prescribing of oral antimicrobial agents for bacterial infections in children who can be treated in an ambulatory setting is the subject of this review. First, restrictive use of antibacterials is advocated to avoid widespread development of bacterial resistance. The use of simple methods, suitable for office use, to discern viral from bacterial infections is recommended. Second, in selecting an antimicrobial agent, the physician should consider a number of distinctive features of each agent. Besides aspects of pharmacokinetics, antibacterial spectrum and tolerability, the number of daily doses and, of particular importance for children, the palatability of suspensions plays an important role in achieving patient compliance. Agents that can be administered once or twice daily and possess an agreeable taste in addition to proven efficacy, established tolerability and a reasonable price are to be preferred. Specific paediatric aspects in choosing among penicillins, cephalosporins, macrolides and other oral antibacterials are discussed. For pharmacoeconomic reasons, the optimal duration of antibacterial treatment and the role of short course therapy for various bacterial infections should be studied in more detail. Finally, rational antimicrobial treatment of common paediatric bacterial infections, such as streptococcal tonsillopharyngitis, acute otitis media, acute sinusitis, bacterial pneumonia, pertussis, Lyme borreliosis (early stage) and lower urinary tract infection is reviewed.

In vivo antibacterial effects of simulated human serum profiles of once-daily versus thrice-daily dosing of amikacin in a Serratia marcescens endocarditis experimental model

Once-daily dosage of aminoglycosides is currently under consideration. The lower toxicity of this regimen has been clearly established, but there are conflicting experimental and clinical data concerning its efficacy. It is inadvisable to optimize human therapy by extrapolation from experimental studies since animal and human pharmacokinetics differ. The simulation of human pharmacokinetics in experimental infectious models would seem to offer a more rational approach. We used computer-controlled infusion of amikacin at a variable flow rate to simulate human pharmacokinetics in a Serratia marcescens rabbit endocarditis model and to compare two therapeutic regimens (once-daily versus thrice-daily doses). The doses corresponded to simulations of 15 and 30 mg/kg of body weight per day in humans, and antibacterial activity was measured in vegetations (Veg) after 24 h of treatment. The results show that the dose corresponding to 15 mg/kg/day failed to produce a significant reduction of CFU (6.8 +/- 0.9 and 6.4 +/- 0.8 log10 CFU/g of Veg, respectively, for once-daily and thrice-daily doses versus 7.6 +/- 1.0 for controls). A significant reduction was observed only for the dose corresponding to 30 mg/kg/day in humans (5.2 +/- 1.5 and 5.4 +/- 1.1 log10 CFU/g of Veg, respectively, for the two regimens). With this model, the efficacy of amikacin was similar for both regimens after 24 h of treatment simulating human pharmacokinetics.

Single or multiple daily doses of aminoglycosides: a meta-analysis

OBJECTIVE

To assess relative efficacy and toxicity of aminoglycosides given by single daily dose compared with multiple daily doses.

DESIGN

Meta-analysis of 21 randomised trials identified through MEDLARS (1966 to January 1995). Data were overviewed with fixed effects and random effects models and with meta-regression analysis.

SUBJECTS

Total of 3091 patients with bacterial infection, most without pre-existing renal disease.

INTERVENTIONS

Patients were randomized to receive aminoglycosides once daily or multiple times daily with similar total daily dose.

MAIN OUTCOME MEASURES

Clinical failure of treatment, nephrotoxicity, ototoxicity, and mortality.

RESULTS

Single daily dose regimen produced a non-significant decrease in risk of antibiotic failures (random effects risk ratio 0.83 (95% confidence interval 0.57 to 1.21)). Benefit of once daily dosing was greater when the percentage of pseudomonas isolates in a trial was larger. Once daily administration reduced risk of nephrotoxicity (fixed effects risk ratio 0.74 (0.54 to 1.00)). Similar trends were noted for patients with febrile neutropenia and for children. There was no significant difference in ototoxicity between the two dosing regimens, but the power of the pooled trials to detect a meaningful difference was low. There was no significant difference in mortality.

CONCLUSIONS

Once daily administration of aminoglycosides in patients without pre-existing renal impairment is as effective as multiple daily dosing, has a lower risk of nephrotoxicity, and no greater risk of ototoxicity. Given the additional convenience and reduced cost, once daily dosing should be the preferred mode of administration.

Once-daily dosing of aminoglycosides

Since their introduction one or more decades ago, aminoglycosides have generally been administered in multiple daily (i.e. twice- or thrice-daily) dosing regimens. However, nephrotoxicity can be reduced in animal models by administering the same total daily dose as one large dose instead of as multiple small doses. In addition, in vitro and in vivo studies that considered the impact of dosing regimens on efficacy suggest that once-daily dosing is equally or more effective compared to multiple daily dosing. Once-daily versus multiple daily dosing regimens have been compared for amikacin, netilmicin, and gentamicin in 24 randomized, clinical trials including a total of 3,181 patients. An analysis of these studies revealed superior results for once-daily regimens with respect to clinical efficacy (89.5% vs. 84.7%, p < 0.001) as well as bacteriological efficacy (88.6% vs. 83.4%, p < 0.01). No statistically significant differences were noted for toxicity. Nevertheless, both nephrotoxicity and ototoxicity occurred less frequently during once-daily dosing (4.5% vs. 5.5% and 4.2% vs. 5.8%, respectively). Finally, once-daily dosing is more economical, since less nursing time and infusion material are required and the efforts for drug monitoring can be reduced. In conclusion, amikacin, netilmicin, and gentamicin can be administered once a day.

Aminoglycosides

Despite their nephrotoxic and ototoxic side effects, AG remain useful antibiotics because of their major, rapid, and dose-dependent bactericidal effects. Combination therapy with an AG appears particularly important in neutropenic and other high-risk patients to provide broad-spectrum bactericidal activity, synergism, and reduction of emergence of resistant pathogens. OD AG therapy is associated with high peak levels in serum that maintain efficacy and low-to-undetectable trough levels in serum that attenuate the risk of toxicity. Administration of short-term OD AG therapy to patients not at risk without renal impairment may not absolutely require dosing monitoring. This therapeutic strategy has been proved useful in clinical trials, now including febrile episodes in neutropenic patients, but it should be avoided during infections in which antimicrobial synergism is required, such as enterococcal endocarditis.

Easier monitoring of aminoglycoside therapy with once-daily dosing schedules

Little has been reported on serum levels attained using once-daily aminoglycoside regimens and their relation to dosage administered and renal function. Consecutive patients with serious infections were randomized to receive gentamicin 4 mg/kg q 24h i.v. (n = 69), gentamicin 1.33 mg/kg q 8h i.v. (n = 46) or netilmicin 5.5 mg/kg q 24h i.v. (n = 59) (with dose reduction in case of renal dysfunction). In the three groups, median first serum trough levels were 0.4, 1.0 and 0.4 mg/l, respectively, and median first serum peak levels were 9.5, 4.7 and 12.2 mg/l (p < 0.01 once-daily vs. thrice-daily regimens). Dose adjustment because of first trough concentrations of > 2 mg/l and/or peak concentrations of < 6 mg/l was required in 6%, 78% and 12% of patients, respectively. Second trough and peak concentrations were significantly higher in the thrice-daily gentamicin group; serum levels remained constant in the other two groups. The six patients in the once-daily groups who developed elevated trough levels later in therapy were characterized in most cases by a decline in renal function.

Ototoxicity and nephrotoxicity of gentamicin vs netilmicin in patients with serious infections. A randomized clinical trial

In the treatment of serious infection by aminoglycoside antibiotics multiple daily treatment with netilmicin is considered to be the least toxic. Studies comparing netilmicin with gentamicin using the less toxic once-daily schedule are lacking. A randomized prospective study was designed to evaluate the efficacy and toxicity of once-daily netilmicin with gentamicin treatment in patients with serious infections. Consecutive patients with serious infections were randomized between gentamicin 4 mg/kg q24h iv or netilmicin 5.5 mg/kg q24h iv. Exclusion criteria were neutropenia or severe renal failure. A good clinical response was observed in 50 of the 54 evaluable patients (92.6%) treated with gentamicin and in 48/52 (92.3%) netilmicin treated patients. Nephrotoxicity developed in 5/72 (6.9%) gentamicin patients and in 10/69 (14.5%) treated with netilmicin. Audiometry was performed with high-frequency audiometry when possible; no significant differences were found between the two aminoglycosides. We conclude that with once-daily treatment no benefit of netilmicin over gentamicin regarding nephro- or ototoxicity could be demonstrated.

What is the evidence for once-daily aminoglycoside therapy?

Aminoglycosides are important antibacterial agents for the treatment of serious infection. Evidence suggests that high peak plasma concentrations must be achieved early in the course of treatment if these agents are to be effective, but prolonged high concentrations may cause ototoxicity and nephrotoxicity. Peak plasma concentrations of 6 to 10 mg/L and trough concentrations of less than 2 mg/L for gentamicin and tobramycin have been traditional goals of therapy. Extensive recent evidence from in vitro, animal and human studies suggests that these target concentrations need revision. Aminoglycosides display concentration-dependent bacterial killing, have a long postantibiotic effect, and induce adaptive resistance in Gram-negative bacteria. All of these factors support the use of larger doses of aminoglycosides that are given less frequently than conventional therapy. Studies in vitro support this approach, showing greater activity when aminoglycosides are given less frequently. Animal studies comparing different dosage intervals have shown varying results, with only a slight bias favouring the longer dosage interval. However, the short elimination half-lives for the drugs in animals limit the applicability of these models to humans. Importantly, there is convincing evidence in animal studies that nephrotoxicity and ototoxicity are both reduced when the same total daily dose is administered in less frequent doses. There have been at least 29 clinical trials comparing once-daily administration of aminoglycosides with conventional administration 2 to 4 times daily. In general, efficacy has not been shown to be different between regimens, although one trial showed an advantage for once-daily administration compared with administration 3 times daily. A small number of trials have shown less nephrotoxicity and ototoxicity with once-daily administration, leading several authors to suggest that there is sufficient evidence to warrant a change to once-daily administration of aminoglycosides. However, once-daily administration has not been well studied in the paediatric population, or in patients with renal failure or endocarditis, and cannot be recommended in these patients as yet. The choice of a 24-hour dosage interval is somewhat arbitrary, and the optimal interval may not necessarily be 24 hours. No studies have included dosage adjustment based on pharmacokinetic modelling methods, and the effect of this on treatment outcome needs to be assessed. The best method of administering aminoglycosides once daily is yet to be determined.

Once-daily administration of aminoglycosides

OBJECTIVE

To provide an overview of the efficacy and adverse effects associated with once-daily administration of aminoglycosides.

DATA SOURCES

An extensive MEDLINE search and review of journals was conducted to identify information for this review.

DATA SYNTHESIS

Aminoglycosides alone or in combination with beta-lactams are commonly used for their activity against gram-negative microorganisms. Numerous studies have been performed comparing efficacy and toxicity of once-daily administration of aminoglycosides with multiple-daily dosing. Two studies have found a significant difference in clinical efficacy between once-daily and multiple-daily dosing of aminoglycosides. Several studies have observed a lower incidence of toxicity with once-daily than multiple-daily dosing, but others have found no difference.

CONCLUSIONS

Review of the literature suggests that once-daily administration of aminoglycosides may be as safe and effective as multiple-daily dosing regimens for the treatment of certain infections caused by gram-negative bacteria.

Aminoglycoside dosing considerations in intensive care unit patients

OBJECTIVE

Factors affecting aminoglycoside dosing requirements in critically ill adult patients were reviewed.

DATA SOURCES

A literature search was performed from 1979 to 1992 and articles pertaining to aminoglycoside dosing were obtained.

STUDY SELECTION

Only studies appearing in peer-reviewed journals were selected. Topics selected included: bactericidal kill kinetics, once-daily dosing regimens, critical illness, toxicity, aminoglycosides, intensive care unit, and lung penetration.

CONCLUSIONS

Studies suggest that larger initial aminoglycoside doses are necessary in critically ill patients (tobramycin/gentamicin 3 mg/kg or amikacin 9 mg/kg) to achieve adequate peak serum concentrations. Current studies have not shown an increase in the incidence of aminoglycoside toxicity when using these larger initial doses. Follow-up monitoring is dependent upon the patient's physiology and risk factors for aminoglycoside-induced toxicity.