Therapeutic Levels of Intravenous Procainamide in Neonates: A Retrospective Assessment

Procainamide pharmacokinetics during extracorporeal membrane oxygenation

Procainamide is a useful agent for management of ventricular arrhythmia, however its disposition and appropriate dosing during extracorporeal membrane oxygenation (ECMO) is unknown. We report experience with continuous procainamide infusion in a critically ill adult requiring venoarterial ECMO for incessant ventricular tachycardia. Pharmacokinetic analysis of procainamide and its metabolite, N-acetylprocainamide (NAPA), was performed using serum and urine specimens. Kidney function was preserved, and sequencing of the N-acetyltransferase 2 gene revealed the patient was a phenotypic slow acetylator. Procainamide volume of distribution and half-life were calculated and found to be similar to healthy individuals. However, despite elevated serum procainamide concentrations, NAPA concentrations remained far lower in the serum and urine. The magnitude of procainamide and NAPA discordance suggested alternative contributors to the deranged pharmacokinetic profile, and we hypothesized NAPA sequestration by the ECMO circuit. Ultimately, the patient received orthotopic cardiac transplantation and was discharged home in stable condition. Procainamide should be used cautiously during ECMO, with close therapeutic drug monitoring of serum procainamide and NAPA concentrations. The achievement of therapeutic NAPA concentrations while maintaining safe serum procainamide concentrations during ECMO support may be challenging.

PICU Pharmacology

The care of the critically-ill child often includes medications used to optimize organ function, treat infections, and provide comfort. Pediatric pharmacology has some key differences that should be leveraged for safe pharmacologic management.

Management of Supraventricular Tachycardia in Infants

Supraventricular tachycardia is the most common tachyarrhythmia encountered in infants. In older children and adults, definitive treatment of the supraventricular tachycardia substrate with catheter ablation is a common approach to management. However, in infants, the risks of catheter ablation are significantly higher, and the patients often outgrow the potential to experience episodes. Therefore, antiarrhythmic medications are often utilized to minimize the likelihood of experiencing episodes. This article reviews the common arrhythmia mechanisms encountered in infants and the medications used to treat these patients.

Arrhythmias in Cardiac Critical Care

OBJECTIVES

Here, we characterize the frequency, mechanisms, clinical impact, and potential treatment options for several arrhythmias commonly encountered in pediatric cardiac critical care.

DATA SOURCE

MEDLINE and PubMed.

CONCLUSIONS

Arrhythmias among children in the cardiac critical care setting are common and clinically important, associated independently with prolonged mechanical ventilation, critical care unit stay, and an increase in mortality. The precise characterization of an arrhythmia may provide clues as to an underlying mechanism as well as serve to guide treatment. Arrhythmia therapy, pharmacologic or otherwise, is directed toward addressing the underlying mechanism, and as such may be applicable to the treatment of more than one specific rhythm disturbance. Decisions concerning therapy must call into consideration an arrhythmia's underlying etiology, mechanism, and associated hemodynamic embarrassment, along with the potential for adverse effects of treatment.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care Antiarrhythmics

OBJECTIVE

Arrhythmias are a common occurrence in critically ill pediatric patients. Pharmacotherapy is a usual modality for treatment and prevention of arrhythmias in this patient population. This review will highlight particular arrhythmias in the pediatric critical care population and discuss salient points of pharmacotherapy of these arrhythmias. The mechanisms of action for the various agents, potential adverse events, place in therapy, and evidence for their use will be summarized.

DATA SOURCES

The literature was searched for articles related to the topic. Expertise of the authors and a consensus of the editors were additional sources of data in the article.

DATA SYNTHESIS

The author team synthesized the current pharmacology and recommendations and present them in this review. Tables were generated to summarize the state of the art evidence-based practice.

CONCLUSION

Specialized knowledge as to the safe and effective use of the antiarrhythmic pharmacotherapy in the intensive care setting can lead to safe and effective rhythm management in patients with complex heart disease.

Optimizing pediatric dosing: a developmental pharmacologic approach

Many physiologic differences between children and adults can result in age-related differences in pharmacokinetics. Understanding the effects of age on bioavailability, volume of distribution, protein binding, hepatic metabolic isoenzymes, and renal elimination can provide insight into optimizing doses for pediatric patients. We performed a search of English-language literature using the MEDLINE database regarding age and pharmacokinetics (1979-July 2008). We then evaluated the literature with an emphasis on drugs with one primary elimination pathway, such as renal clearance or a pathway involving a single metabolic isoenzyme. Our mechanistic-based analysis revealed that children need weight-corrected doses that are substantially higher than adult doses for drugs that are metabolically eliminated solely by the specific cytochrome P450 (CYP) isoenzymes CYP1A2, CYP2C9, and CYP3A4. In contrast, weight-corrected doses for drugs eliminated by renal excretion or metabolism involving CYP2C19, CYP2D6, N-acetyltransferase 2, or uridine diphosphate glucuronosyltransferases are similar in children and adults. In children, bioavailability of drugs with high first-pass metabolism is decreased for drugs metabolized by CYP1A2, CYP2C9, and CYP3A4. Limited data suggest that by age 5 years, bioavailability of drugs affected by efflux transporters should be equivalent to that of adults. Using a pharmacokinetics-based approach, rational predictions can be made for the effects of age on drugs that undergo similar pathways of elimination, even when specific pharmacokinetic data are limited or unavailable.