Rational Use of Medicines in Neonates: Current Observations, Areas for Research and Perspectives

Grading the level of evidence of neonatal pharmacotherapy: midazolam and phenobarbital as examples

BACKGROUND

Many drugs are used off-label or unlicensed in neonates. This does not mean they are used without evidence or knowledge. We aimed to apply and evaluate the Grading and Assessment of Pharmacokinetic-Pharmacodynamic Studies (GAPPS) scoring system for the level of evidence of two commonly used anti-epileptic drugs.

METHODS

Midazolam and phenobarbital as anti-epileptics were evaluated with a systematic literature search on neonatal pharmacokinetic (PK) and/or pharmacodynamic [PD, (amplitude-integrated) electroencephalography effect] studies. With the GAPPS system, two evaluators graded the current level of evidence. Inter-rater agreement was assessed for dosing evidence score (DES), quality of evidence (QoE), and strength of recommendation (REC).

RESULTS

Seventy-two studies were included. DES scores 4 and 9 were most frequently used for PK, and scores 0 and 1 for PD. Inter-rater agreements on DES, QoE, and REC ranged from moderate to very good. A final REC was provided for all PK studies, but only for 25% (midazolam) and 33% (phenobarbital) of PD studies.

CONCLUSIONS

There is a reasonable level of evidence concerning midazolam and phenobarbital PK in neonates, although using a predefined target without integrated PK/PD evaluation. Further research is needed on midazolam use in term neonates with therapeutic hypothermia, and phenobarbital treatment in preterms.

IMPACT

There is a reasonable level of evidence concerning pharmacotherapy of midazolam and phenobarbital in neonates. Most evidence is however based on PK studies, using a predefined target level or concentration range without integrated, combined PK/PD evaluation. Using the GAPPS system, final strength of recommendation could be provided for all PK studies, but only for 25% (midazolam) to 33% (phenobarbital) of PD studies. Due to the limited PK observations of midazolam in term neonates with therapeutic hypothermia, and of phenobarbital in preterm neonates these subgroups can be identified for further research.

Drug utilisation in neonatal units in England and Wales: a national cohort study

PURPOSE

To describe drug utilisation patterns in neonatal units.

METHODS

Retrospective observational cohort study using data held in the National Neonatal Research Database (NNRD) for neonatal units in England and Wales including infants born at 23 to 44 weeks' gestational age (GA) from 01 January 2010 to 31 December 2017.

RESULTS

The cohort included 17,501 (3%) extremely preterm infants; 40,607 (7%) very preterm infants; 193,536 (31%) moderate-to-late preterm infants; and 371,606 (59%) term infants. The number of unique drugs received by an infant (median (IQR)) increased with decreasing GA: 17 (11-24) in extremely preterm, 7 (5-11) in very preterm, 3 (0-4) in moderate-to-late preterm, and 3 (0-3) in term infants. The two most frequently prescribed drugs were benzylpenicillin and gentamicin in all GA groups, and caffeine in extremely preterm. Other frequently used drugs among preterm infants were electrolytes, diuretics and anti-reflux medications. Among infants <32 weeks' GA, the largest increase in use was for surfactant (given on the neonatal unit), caffeine and probiotics, while domperidone and ranitidine had the largest decline.

CONCLUSION

Antibiotics, for all GAs and caffeine, among preterm infants, are the most frequently used drugs in neonatal medicine. Preterm infants are exposed to a high burden of drugs, particularly antibiotics. Changing patterns in use reflect the emergence of evidence in some areas but several non-evidence-based drugs continue to be used widely. Improvements are needed to ensure rational drug use on neonatal units.

REGISTRATION

ClinicalTrials.gov (NCT03773289). Date of registration 21 Dec 2018.

Prescription of Aminoglycosides in 23 French Neonatal Intensive Care Units

Background: Aminoglycosides are the most prescribed antibiotics in neonatal intensive care units (NICU). Reducing exposure to antibiotics in the NICU is highly desirable, particularly through benchmarking methods. Methods: Description of aminoglycosides prescriptions in 23 French NICU using the same computerized system over a 4-year period (2017–2020). A benchmarking program of antibiotics prescription was associated. Results: The population included 53,818 patients. Exposition rates to gentamicin and amikacin were 31.7% (n = 17,049) and 9.1% (n = 4894), respectively. Among neonates exposed to gentamicin, 90.4% of gentamicin and 77.6% of amikacin treatments were started within the 1st week of life. Among neonates exposed to amikacin, 77.6% started amikacin within the 1st week. The average daily dose of gentamicin at first prescription increased over the study period from 3.9 in 2017 to 4.4 mg/kg/d in 2020 (p < 0.0001). Conversely, the corresponding amikacin daily doses decreased from 13.0 in 2017 to 12.3 mg/kg/d in 2020 (p = 0.001). The time interval between the first 2 doses of gentamicin was mainly distributed in 3 values during the first week of life: 49.4% at 24 h, 26.4% at 36 h, and 22.9% at 48 h. At first amikacin prescription, the time interval was distributed in 4 categories: 48% at 24 h, 4.1% at 30 h, 8.5% at 36 h, and 37.1% at 48 h. As compared to literature guidelines, the rates of overdose and underdose in gentamicin (1.5% and 2.7%) and amikacin (0.3% and 1.0%). They significantly decreased for gentamicin over the study period. In multivariate analysis, the factors significantly associated with GENT overdose were the year of admission, prematurity, length of stay, and duration of the treatment. Conclusion: This prescription strategy ensured a low rate of overdose and underdose, and some benefits of the benchmarking program is suggested.

Cross-sectional study of drug utilisation in a Chinese neonatal unit

Objective

This study aimed to describe drug utilisation in a large Chinese neonatal unit and to compare the findings with those from other countries.

Methods

Data were collected from electronic medical records. Prescription drugs were defined as the number of unique medication names for each patient. Medicine doses were defined as the total number of doses of all medicines administered. Information was collected regarding drugs prescribed to inpatients between March 1 and April 1 2018 in the neonatal intensive care unit and the general neonatal ward of West China Second University Hospital.

Results

The 319 neonates received 1276 prescription drugs and 11,410 medicine doses involving 81 drugs. Vitamin K1, hepatitis B vaccine, and cefoperazone-sulbactam were the three most frequently prescribed drugs. Antimicrobials were the most frequently used group of medicines, with cefoperazone-sulbactam and piperacillin-tazobactam the most frequently used in an off-label manner. Domperidone and simethicone were both widely used.

Conclusions

The most commonly prescribed antimicrobials differed greatly from those reported for other countries. The evidence base for the use of some medicines is poor, and is indicative of irrational prescribing.

Pharmacokinetic modelling and Bayesian estimation-assisted decision tools to optimize vancomycin dosage in neonates: only one piece of the puzzle

Introduction: Vancomycin is commonly administered to neonates, while observational data on therapeutic drug monitoring (TDM, trough levels) suggest that vancomycin exposure and dosage remain substandard. Area covered: Data on vancomycin pharmacokinetics (PK) and its covariates are abundant. Consequently, modeling is an obvious tool to improve targeted exposure, with a shift from TDM trough levels to area under the curve (AUC_24h) targets, as in adults. Continuous administration appeared as a practice to facilitate AUC_24h target attainment, while Bayesian model-supported targeting emerged as a novel tool. However, the AUC_24h/MIC (minimal inhibitory concentration) target itself should consider neonate-specific aspects (bloodstream infections, coagulase-negative staphylococci, protein binding, underexplored causes of variability, like assays, preparation and administration inaccuracies, or missing covariates). Expert opinion: To improve targeted exposure in neonates, initial vancomycin prescription should be based on 'a priori model-based individual dosing' using validated dosing regimens, followed by further tailoring by dosing optimization applying Bayesian estimation-assisted TDM. Future research should focus on the feasibility to integrate these tools (individualized dosing, Bayesian models) in clinical practice, and to perform PK/PD studies in the relevant animal models and human neonatal setting (coagulase-negative staphylococci, bloodstream infections).

Rational Use of Antibiotics in Neonates: Still in Search of Tailored Tools

Rational medicine use in neonates implies the prescription and administration of age-appropriate drug formulations, selecting the most efficacious and safe dose, all based on accurate information on the drug and its indications in neonates. This review illustrates that important uncertainties still exist concerning the different aspects (when, what, how) of rational antibiotic use in neonates. Decisions when to prescribe antibiotics are still not based on robust decision tools. Choices (what) on empiric antibiotic regimens should depend on the anticipated pathogens, and the available information on the efficacy and safety of these drugs. Major progress has been made on how (beta-lactam antibiotics, aminoglycosides, vancomycin, route and duration) to dose. Progress to improve rational antibiotic use necessitates further understanding of neonatal pharmacology (short- and long-term safety, pharmacokinetics, duration and route) and the use of tailored tools and smarter practices (biomarkers, screening for colonization, and advanced therapeutic drug monitoring techniques). Implementation strategies should not only facilitate access to knowledge and guidelines, but should also consider the most effective strategies (‘skills’) and psychosocial aspects involved in the prescription process: we should be aware that both the decision not to prescribe as well as the decision to prescribe antibiotics is associated with risks and benefits.