Epileptogenic potential of carbapenem agents: mechanism of action, seizure rates, and clinical considerations

Pediatric head and neck complications of Streptococcus pneumoniae before and after PCV7 vaccination

OBJECTIVE

To discuss pediatric head and neck complications of pneumococcal infections before and after the introduction of the PCV7 vaccine.

STUDY DESIGN

Cross-sectional analysis of a national database.

STUDY SETTING

Kids National Inpatient Database.

METHODS

A retrospective review of the Kids National Inpatient Database yielded 31,738 pediatric reports involving complications of meningitis, mastoiditis, periorbital cellulitis, and Bezold abscesses due to Streptococcus pneumoniae diagnoses. Each report was analyzed for incidence, length of stay, mean hospital cost, and inpatient admittance from the emergency department. Finally, we calculated the expected annual incidence of each complication via variance-weighted analysis to determine the expected incidence if the vaccine was not administered.

RESULTS

We identified a significant decrease in the incidence of several complications after the introduction of the PCV7 vaccine and also when comparing these findings to our predicted incidence calculations if the vaccine was not administered. Inpatient admittance from the emergency department for Bezold abscess, periorbital cellulitis, mastoiditis, and meningitis was significantly increased in the pediatric age group (ages 1-4; P < .05). Furthermore, there was a significant increase in the cost to provide care for each of the described conditions (P < .05).

CONCLUSIONS

The PCV7 vaccine produced a measurable reduction in head and neck complications associated with S pneumoniae. However, our data suggest that these benefits were also met with increased inpatient admittance from the emergency department, hospital costs, and length of stay, each of which may be attributed to the selection of a more pathogenic subtype.

Adverse neurologic effects of medications commonly used in the intensive care unit

Adverse drug effects often complicate the care of critically ill patients. Therefore, each patient's medical history, maintenance medication, and new therapies administered in the intensive care unit must be evaluated to prevent unwanted neurologic adverse effects. Optimization of pharmacotherapy in critically ill patients can be achieved by considering the need to reinitiate home medications, and avoiding drugs that can decrease the seizure threshold, increase sedation and cognitive deficits, induce delirium, increase intracranial pressure, or induce fever. Avoiding medication-induced neurologic adverse effects is essential in critically ill patients, especially those with neurologic injury.

The risk of seizures among the carbapenems: a meta-analysis

OBJECTIVES

A consensus exists among clinicians that imipenem/cilastatin is the most epileptogenic carbapenem, despite inconsistencies in the literature.

METHODS

We conducted a meta-analysis of all randomized controlled trials comparing carbapenems with each other or with non-carbapenem antibiotics to assess the risk of seizures for imipenem, meropenem, ertapenem and doripenem.

RESULTS

In the risk difference (RD) analysis, there were increased patients with seizure (2 per 1000 persons, 95% CI 0.001, 0.004) among recipients of carbapenems versus non-carbapenem antibiotics. This difference was largely attributed to imipenem as its use was associated with an additional 4 patients per 1000 with seizure (95% CI 0.002, 0.007) compared with non-carbapenem antibiotics, whereas none of the other carbapenems was associated with increased seizure. Similarly, in the pooled OR analysis, carbapenems were associated with a significant increase in the risk of seizures relative to non-carbapenem comparator antibiotics (OR 1.87, 95% CI 1.35, 2.59). The ORs for risk of seizures from imipenem, meropenem, ertapenem and doripenem compared with other antibiotics were 3.50 (95% CI 2.23, 5.49), 1.04 (95% CI 0.61, 1.77), 1.32 (95% CI 0.22, 7.74) and 0.44 (95% CI 0.13, 1.53), respectively. In studies directly comparing imipenem and meropenem, there was no difference in epileptogenicity in either RD or pooled OR analyses.

CONCLUSIONS

The absolute risk of seizures with carbapenems was low, albeit higher than with non-carbapenem antibiotics. Although imipenem was more epileptogenic than non-carbapenem antibiotics, there was no statistically significant difference in the imipenem versus meropenem head-to-head comparison.

Clinical pharmacology of carbapenems in neonates

Carbapenems are an effective tool to treat complicated bacterial infections. This review aims to summarize the available information on carbapenems in neonates to guide clinicians on drug choice and indications in neonates. Moreover, identification of knowledge gaps may stimulate researchers to design studies to further improve pharmacotherapy in neonates. To do so, a bibliographic search [infant/newborn and meropenem, imipenem, panipenem, ertapenem, doripenem or imipenem] was performed (PubMed, EMBASE) and public clinical trial registries (clinicaltrials.gov, EU registry) were searched to summarize the available information. Carbapenem clearance in neonates is low. Variability relates to maturation (weight, age) and renal function (creatinine clearance), while observations in neonates with renal failure are absent. Pharmacodynamics are almost exclusively limited to meropenem, and the available information will further increase (NeoMero-1-2, necrotizing enterocolitis, meningitis). Finally, there are also some ongoing doripenem pharmacokinetics (PK) studies in neonates. It was concluded that observations on carbapenems in neonates are limited, but studies (NeoMero, doripenem) are ongoing. Until this information becomes available, off label prescription of meropenem seems to be the most reasonable choice when a carbapenem is appropriate. Knowledge gaps relate to PK in neonates with renal failure and to the potential benefit of prolonged compared to short duration of infusion.

Adverse events associated with meropenem versus imipenem/cilastatin therapy in a large retrospective cohort of hospitalized infants

BACKGROUND

Carbapenems are commonly used in hospitalized infants despite a lack of complete safety data and associations with seizures in older children. We compared the incidence of adverse events in hospitalized infants receiving meropenem versus imipenem/cilastatin.

METHODS

We conducted a retrospective cohort study of 5566 infants treated with meropenem or imipenem/cilastatin in neonatal intensive care units managed by the Pediatrix Medical Group between 1997 and 2010. Multivariable conditional logistic regression was performed to evaluate the association between carbapenem therapy and adverse events, controlling for infant factors and severity of illness.

RESULTS

Adverse events were more common with use of meropenem compared with imipenem/cilastatin (62.8/1000 infant days versus 40.7/1000 infant days, P < 0.001). There was no difference in seizures with meropenem versus imipenem/cilastatin (adjusted odds ratio 0.96; 95% confidence interval: 0.68, 1.32). The incidence of death, as well as the combined outcome of death or seizure, was lower with meropenem use-odds ratio 0.68 (0.50, 0.88) and odds ratio 0.77 (0.62, 0.95), respectively.

CONCLUSION

In this cohort of infants, meropenem was associated with more frequent but less severe adverse events when compared with imipenem/cilastatin.

Comparative pharmacokinetics, pharmacodynamics, and tolerability of ertapenem 1 gram/day administered as a rapid 5-minute infusion versus the standard 30-minute infusion in healthy adult volunteers

STUDY OBJECTIVE

To compare ertapenem pharmacokinetics, pharmacodynamics, and tolerability when administered as a rapid 5-minute infusion to the standard 30-minute infusion.

DESIGN

Prospective, randomized, crossover pharmacokinetic study.

SETTING

Clinical research center.

SUBJECTS

Twelve healthy adult volunteers.

INTERVENTION

Each subject received ertapenem 1 g intravenously, administered either as a rapid 5-minute infusion or the standard 30-minute infusion, every 24 hours for 3 days (first phase); after a 4-day washout period, each subject then received the other infusion every 24 hours for 3 days (second phase).

MEASUREMENTS AND MAIN RESULTS

Plasma samples were collected after the first and third (steady-state) doses of each study phase, and protein binding was assessed by use of ultrafiltration. Pharmacokinetic analyses were conducted using noncompartmental and compartmental methods. A 5000-subject Monte Carlo simulation was used to assess the probability of target attainment for free drug concentration remaining above the minimum inhibitory concentration (MIC) for 40% or greater of the dosing interval (40% fT > MIC) over an MIC range. Ertapenem was well tolerated and adverse events were similar for both infusions. The ertapenem steady-state mean ± SD maximum concentrations were 193.3 ± 43.3 and 165.7 ± 20.4 mg/L for the 5- and 30-minute infusions, respectively; the mean ± SD areas under the concentration-time curves from 0-24 hours were 561.2 ± 77.0 and 531.3 ± 56.9 μg · hr/ml (geometric mean ratio 1.008, 90% confidence interval 0.999-1.017), respectively. Protein binding was concentration dependent (range 87.9-98.9%). A two-compartment model best described ertapenem pharmacokinetics with the following parameter estimates: clearance 1.89 ± 0.19 L/hr, volume of central compartment 5.04 ± 0.56 L, and transfer constants k12 0.43 ± 0.08/hr and k21 0.44 ± 0.07/hr. The probabilities of target attainment for 5- and 30-minute infusions were 97.0% and 97.9% at an MIC of 0.25 mg/L and 1.7% and 2.8% at an MIC of 0.5 mg/L, respectively.

CONCLUSION

Ertapenem administered as a rapid 5-minute infusion provides a well tolerated, bioequivalent, and pharmacodynamically equivalent regimen to the 30-minute infusion at clinically relevant MICs.

Antibiotic Use in Home Health

Cost containment measures within hospital systems push for earlier discharges on stable patients. Due to patient placement difficulties and costs associated with skilled facilities, antibiotic use in home health care settings is becoming a common occurrence. This trend will likely increase as care continues to shift to outpatient areas. Lack of sufficient serum drug concentrations needed in severe infections and increasing resistance to many of the oral options often necessitates the use of the intravenous (IV) route. Home health care practitioners may have minimal information on patients or limited experience with IV antibiotics that may impact quality of care. This review summarizes key points relevant to IV antibiotics routinely used by home health prescribers, nurses, technicians, and care managers. This review will focus on antibacterial agents including vancomycin, aminoglycosides, beta-lactams, daptomycin, tigecycline, and telavancin. Appropriate dosing, indications, adverse events, monitoring parameters, and feasibility of using IV antibiotics are discussed.