Long-term use of clonidine in a critically-ill infant

Pharmacology of Common Analgesic and Sedative Drugs Used in the Neonatal Intensive Care Unit

In this review of analgesic and sedation medication in neonates, important classes of old and newer medications commonly used in the neonatal intensive care unit setting are discussed. In addition to drug metabolism, efficacy, and safety for individual drugs, new insights into multimodal analgesic approaches suggest ways in which multiple analgesic drug classes can be combined to maximize efficacy and minimize toxicity. Opiate pharmacogenetics and the potential for a precision therapeutics approach is explored, with a final description of gaps in knowledge and a call for future research of pain and sedation control in the neonatal population.

Clonidine for Sedation and Analgesia and Withdrawal in Critically Ill Infants and Children

The need for sedation and analgesia and treatment of iatrogenic drug withdrawal is common in critically ill children. First-line therapy typically includes opioid agonists. However, clonidine, a central α₂ agonist, has been suggested as a treatment option for sedation and analgesia and iatrogenic drug withdrawal. Therefore, we conducted a literature search to identify articles evaluating the use of enteral (PO) and transdermal clonidine in critically ill infants and children for sedation and analgesia and treatment of iatrogenic drug withdrawal. The literature search was limited to English-language articles in Medline (1946-May 2016), Embase (1988-May 2016), and International Pharmaceutical Abstracts (1970-May 2016). Reference citations from relevant articles were also reviewed. Ten case reports and studies, representing a total of 114 children receiving clonidine, were included. Fifty patients (43.9%) received clonidine for sedation and analgesia while mechanically ventilated, and 33 (29.0%) received clonidine for treatment or prevention of drug withdrawal. The remaining 31 patients (27.1%) were included in a pharmacokinetic study that did not evaluate clinical outcomes. Seventy-nine patients (69.3%) received PO clonidine, with a dosage range of 2-15 µg/kg/day divided every 6-8 hours. Thirty-five patients (30.7%) received transdermal clonidine, with a dosage range of 2.3-20 µg/kg/day. Whole, cut, and occluded transdermal patches were used in the reports. Patients receiving cut patches had more variable and significantly higher serum clonidine concentrations than those receiving whole patches. Only three studies reported that the PO clonidine dose was tapered at the end of therapy; however, no report specifically described the process. The two most common adverse events reported with PO and transdermal clonidine were bradycardia and hypotension. PO and transdermal clonidine have a potential role for sedation and analgesia and drug withdrawal in critically ill infants and children. The use of cut transdermal patches should be avoided. Future prospective studies are needed to further define clonidine's role as adjunct therapy or monotherapy.

Continuous infusion of clonidine in ventilated newborns and infants: a randomized controlled trial

OBJECTIVES

To assess the influence of an infusion of clonidine 1 μg/kg/hr on fentanyl and midazolam requirement in ventilated newborns and infants.

DESIGN

Prospective, double-blind, randomized controlled multicenter trial. Controlled trials.com/ISRCTN77772144.

SETTING

Twenty-eight level 3 German PICUs/neonatal ICUs.

PATIENTS

Ventilated newborns and infants: stratum I (1-28 d), stratum II, (29-120 d), and stratum III (121 d to 2 yr).

INTERVENTIONS

Patients received clonidine 1 μg/kg/hr or placebo on day 4 after intubation. Fentanyl and midazolam were adjusted to achieve a defined level of analgesia and sedation according to Hartwig score.

MEASUREMENTS AND MAIN RESULTS

Two hundred nineteen infants were randomized; 212 received study medication, 69.7% were ventilated in the postoperative care and 30.3% for other reasons. Primary endpoint: consumption of fentanyl and midazolam in the 72 hours following the onset of study medication (main observation period) in the overall study population. The confirmatory analysis of the overall population showed no difference in the consumption of fentanyl and midazolam. Explorative age-stratified analysis demonstrated that in stratum I (n = 112) the clonidine group had a significantly lower consumption of fentanyl (clonidine: 2.1 ± 1.8 μg/kg/hr, placebo: 3.2 ± 3.1 μg/kg/hr; p = 0.032) and midazolam (clonidine: 113.0 ± 100.1 μg/kg/hr, placebo: 180.2 ± 204.0 μg/kg/hr; p = 0.030). Strata II (n = 43) and III (n = 46) showed no statistical difference. Sedation and withdrawal-scores were significantly lower in the clonidine group of stratum I (p < 0.001). Frequency of severe adverse events did not differ between groups.

CONCLUSIONS

Clonidine 1 μg/kg/hr in ventilated newborns reduced fentanyl and midazolam demand with deeper levels of analgesia and sedation without substantial side effects. This was not demonstrated in older infants, possibly due to lower clonidine serum levels.

Long-term consequences of drugs on the paediatric cardiovascular system

Many pharmacological and toxicological actions of drugs in children cannot be fully predicted from adult clinical experience or from standard non-clinical toxicology studies. Numerous drugs have direct or indirect pharmacological effects on the heart and are prescribed for children of all ages. Toxicity or secondary effects may be immediate or delayed for years after drug exposure has ceased. Originally, the aim of this review was to compile information on the effect of specific drugs on the post-natal development of the cardiovascular system and to examine long-term follow-up of the use of cardio-active drugs in children. The limited database of published information caused the original question to evolve into an examination of the medical literature for three areas of information: (i) whether vulnerable developmental windows have been identified that reflect the substantial functional development that the cardiovascular system undergoes after birth; (ii) what is known about pharmacological perturbation of development; and (iii) what the likelihood is of drug exposure during childhood. We examined different scenarios for exposure including random, isolated exposure, conditions historically associated with adults, primary or secondary cardiac disease, psychiatric and neurological conditions, asthma, cancer and HIV. Except for random, isolated drug exposures, each category of possible exposure contained numerous drugs known to have either primary or secondary effects on the cardiovascular system or to influence factors associated with atherosclerosis. It is likely that a significant number of children will be prescribed drugs having either direct or indirect effects upon the immature cardiovascular system. A confounding factor is the simultaneous use of over-the-counter medications and herbal or nutraceutical preparations that a patient, parent or guardian does not mention to a prescribing physician. Metabolism is also important in assessing drug effects in children. Differences in body water : body fat ratio, age-related gastrointestinal absorption, distribution, excretion, renal function and drug metabolizing capabilities make it possible for children to have a different metabolite profile for a drug compared with adults. There is little examination of drug effects on the interdependent processes of cardiac maturation and less examination of metabolite effects. It is difficult to identify delayed toxicities in children as these adverse events may take years to manifest with many patients lost to follow-up. Clearly this is an area of study where intermediate endpoints and surrogate markers would be of great benefit. Pharmacogenomics may be useful in providing markers of increased risk or susceptibility. A perspective must be kept in balancing the possibility of a problem with the very real benefits that many children experience from the use of these pharmaceuticals.

Efficacy of sedation regimens to facilitate mechanical ventilation in the pediatric intensive care unit: a systematic review

OBJECTIVE

Children admitted to pediatric intensive care units (PICUs) often receive sedatives to facilitate mechanical ventilation. However, despite their widespread use, data supporting appropriate dosing, safety, and optimal regimens for sedation during mechanical ventilation are lacking. Therefore, we conducted a systematic review of published data regarding efficacy of sedation to facilitate mechanical ventilation in PICU patients. Our primary objective was to identify and evaluate the quality of evidence supporting sedatives used in PICUs for this purpose.

DATA SOURCES

We searched MEDLINE, EMBASE, and The Cochrane Registry of Clinical Trials from 1966 to June 2008 to identify published articles evaluating sedation regimens to facilitate mechanical ventilation in PICU patients.

STUDY SELECTION

We included only those studies of intubated PICU or pediatric cardiac intensive care unit patients receiving pharmacologic agents to facilitate mechanical ventilation that reported quality of sedation as an outcome.

DATA EXTRACTION

We analyzed studies separately for study type and by agents being studied. Studies were appraised using criteria of particular importance for reviews evaluating sedatives.

DATA SYNTHESIS

Our search strategy yielded 39 studies, including 3 randomized trials, 15 cohort studies, and 21 cases series or reports. The 39 studies evaluated a total of 39 different sedation regimens, with 21 different scoring systems, in a total of 901 PICU/cardiac intensive care unit patients ranging in age from 3 days to 19 years old. Most of the studies were small (<30 patients), and only four studies compared one or more agents to another. Few studies thoroughly evaluated drug safety, and only one study met all quality criteria.

CONCLUSIONS

Despite the widespread use of sedatives to facilitate mechanical ventilation in the PICU, we found that high-quality evidence to guide clinical practice is still limited. Pediatric randomized, controlled trials with reproducible methods and assessment of drug safety are needed.