The use of short-acting nifedipine in pediatric patients with hypertension

Primary and secondary paediatric hypertension

High blood pressure (BP) or hypertension is a well known risk factor for developing heart attack, stroke, atrial fibrillation and renal failure. Although in the past hypertension was supposed to develop at middle age, it is now widely recognized that it begins early during childhood. As such, approximately 5-10% of children and adolescents are hypertensive. Unlike that previously reported, it is now widely accepted that primary hypertension is the most diffuse form of high BP encountered even in paediatric age, while secondary hypertension accounts just for a minority of the cases. There are significant differences between that outlined by the European Society of Hypertension (ESH), the European Society of Cardiology (ESC), and the last statement by the American Academy of Pediatrics (AAP) concerning the BP cut-offs to identify young hypertensive individuals. Not only that, but the AAP have also excluded obese children in the new normative data. This is undoubtedly a matter of concern. Conversely, both the AAP and ESH/ESC agree that medical therapy should be reserved just for nonresponders to measures like weight loss/salt intake reduction/increase in aerobic exercise. Secondary hypertension often occurs in aortic coarctation or chronic renal disease patients. The former can develop hypertension despite early effective repair. This is associated with significant morbidity and is arguably the most important adverse outcome in about 30% of these subjects. Also, syndromic patients, for example those with Williams syndrome, may suffer from a generalized aortopathy, which triggers increased arterial stiffness and hypertension. This review summarizes the state-of-the-art situation regarding primary and secondary paediatric hypertension.

Virtual Clinical Trials Guided Design of an Age-Appropriate Formulation and Dosing Strategy of Nifedipine for Paediatric Use

The rapid onset of action of nifedipine causes a precipitous reduction in blood pressure leading to adverse effects associated with reflex sympathetic nervous system (SNS) activation, including tachycardia and worsening myocardial and cerebrovascular ischemia. As a result, short acting nifedipine preparations are not recommended. However, importantly, there are no modified release preparations of nifedipine authorised for paediatric use, and hence a paucity of clinical studies reporting pharmacokinetics data in paediatrics. Pharmacokinetic parameters may differ significantly between children and adults due to anatomical and physiological differences, often resulting in sub therapeutic and/or toxic plasma concentrations of medication. However, in the field of paediatric pharmacokinetics, the use of pharmacokinetic modelling, particularly physiological-based pharmacokinetics (PBPK), has revolutionised the ability to extrapolate drug pharmacokinetics across age groups, allowing for pragmatic determination of paediatric plasma concentrations to support drug licensing and clinical dosing. In order to pragmatically assess the translation of resultant dissolution profiles to the paediatric populations, virtual clinical trials simulations were conducted. In the context of formulation development, the use of PBPK modelling allowed the determination of optimised formulations that achieved plasma concentrations within the target therapeutic window throughout the dosing strategy. A 5 mg sustained release mini-tablet was successfully developed with the duration of release extending over 24 h and an informed optimised dosing strategy of 450 µg/kg twice daily. The resulting formulation provides flexible dosing opportunities, improves patient adherence by reducing frequent administration burden and enhances patient safety profiles by maintaining efficacious levels of consistent drug plasma levels over a sustained period of time.

Oral agents for acute severe hypertension in children with minimal or no symptoms

Acute hypertension is common among children admitted to hospital, and large or rapid increases in blood pressure place children at risk of complications such as posterior reversible encephalopathy syndrome. Guidelines in the United States and Europe now include definitions guiding the identification of acute severe hypertension (otherwise known as hypertensive crisis) and its management. This review discusses these recommendations and the appropriate use of oral antihypertensive agents for children with minimal or no symptoms. We focus on the role of oral calcium channel blockers, including isradipine (a second-generation dihydropyridine), given recent changes to regulatory approvals in Australia. The differing pharmacokinetic and pharmacodynamic properties of agents are compared, with the aim of facilitating directed drug selection and dosing.

Management of Hypertensive Crises in Children: A Review of the Recent Literature

Hypertensive emergency is a life-threatening condition associated with severe hypertension and organ damage, such as neurological, renal or cardiac dysfunction. The most recent guidelines on pediatric hypertension, the 2016 European guidelines and the 2017 American guidelines, provide recommendations on the management of hypertensive emergencies, however in pediatric age robust literature is lacking and the available evidence often derives from studies conducted in adults. We reviewed PubMed and Cochrane Library from January 2017 to July 2021, using the following search terms: "hypertension" AND "treatment" AND ("emergency" OR "urgency") to identify the studies. Five studies were analyzed, according to our including criteria. According to the articles reviewed in this work, beta-blockers seem to be safe and effective in hypertensive crises, more than sodium nitroprusside, although limited data are available. Indeed, calcium-channel blockers seem to be effective and safe, in particular the use of clevidipine during the neonatal age, although limited studies are available. However, further studies should be warranted to define a univocal approach to pediatric hypertensive emergencies.

A Practical Guide to the Management of Severe Hypertension in Children

Severe hypertension in children may result in life-threatening complications. Although there has not been extensive research in this area in children, and recommendations are mostly derived from adult data, in the last few years, there have been more pediatric studies on the safety and effectiveness of antihypertensives. The clinical presentation of a child with severe hypertension varies and may be completely asymptomatic or include signs and symptoms of end-organ damage. Treatment of a child with severe hypertension is emergent and should be done concomitantly with the evaluation.

Hypertensive Crisis in Pediatric Patients: An Overview

Hypertensive crisis can be a source of morbidity and mortality in the pediatric population. While the epidemiology has been difficult to pinpoint, it is well-known that secondary causes of pediatric hypertension contribute to a greater incidence of hypertensive crisis in pediatrics. Hypertensive crisis may manifest with non-specific symptoms as well as distinct and acute symptoms in the presence of end-organ damage. Hypertensive emergency, the form of hypertensive crisis with end-organ damage, may present with more severe symptoms and lead to permanent organ damage. Thus, it is crucial to evaluate any pediatric patient suspected of hypertensive emergency with a thorough workup while acutely treating the elevated blood pressure in a gradual manner. Management of hypertensive crisis is chosen based on the presence of end-organ damage and can range from fast-acting intravenous medication to oral medication for less severe cases. Treatment of such demands a careful balance between decreasing blood pressure in a gradual manner while preventing damage end-organ damage. In special situations, protocols have been established for treatment of hypertensive crisis, such as in the presence of endocrinologic neoplasms, monogenic causes of hypertension, renal diseases, and cardiac disease. With the advent of telehealth, clinicians are further able to extend their reach of care to emergency settings and aid emergency medical service (EMS) providers in real time. In addition, further updates on the evolving topic of hypertension in the pediatric population and novel drug development continues to improve outcomes and efficiency in diagnosis and management of hypertension and consequent hypertensive crisis.

Hypertensive crisis in children and adolescents

Hypertensive crisis is a relatively rare condition in children. However, if not treated, it might be life-threatening and lead to irreversible damage of vital organs. Clinical presentation of patients with hypertensive crisis can vary from very mild (hypertensive urgency) to severe symptoms (hypertensive emergency) despite similarly high blood pressure (BP). Individualized assessment of patients presenting with high BP with emphasis on the evaluation of end-organ damage rather than on the specific BP number is a key in guiding physician's initial management of a hypertensive crisis. The main aim of the treatment of hypertensive crisis is the prevention or treatment of life-threatening complications of hypertension-induced organ dysfunction, including neurologic, ophthalmologic, renal, and cardiac complications. While the treatment strategy must be directed toward the immediate reduction of BP to reduce the hypertensive damage to these organs, it should not be at a too fast rate to cause hypoperfusion of vital organs by an excessively rapid reduction of BP. Thus, intravenous continuous infusions rather than intravenous boluses of antihypertensive medications should be the preferable mode of initial treatment of children with hypertensive emergency.

Epidemiology and Management of Children with Hypertensive Crisis: A Single-Center Experience

Most children who present with hypertensive crisis have a secondary cause for hypertension. This study describes the epidemiology and management of children with hypertensive crisis. A retrospective cohort study was done in a tertiary pediatric hospital from 2009 to 2015. Thirty-seven patients were treated for hypertensive crisis. Twelve (32.4%) patients were treated for hypertensive emergency. The majority of our patients (33 [89.1%]) had a secondary cause of hypertension. The most common identifiable cause of hypertension was a renal pathology (18/37 [48.6%]). Oral nifedipine (23 [62.1%]) was the most frequently used antihypertensive, followed by intravenous labetalol (8 [21.6%]). There were no mortalities or morbidities. Hypertensive crisis in children is likely secondary in nature. Oral nifedipine and intravenous labetalol are both effective treatments.

Evaluation and management of elevated blood pressures in hospitalized children

Elevated blood pressures (BP) are common among hospitalized children and, if not recognized and treated promptly, can lead to potentially significant consequences. Even though we have normative BP data and well-developed guidelines for the diagnosis and management of hypertension (HTN) in the ambulatory setting, our understanding of elevated BPs and their relationship to HTN in hospitalized children is limited. Several issues have hampered our ability to diagnose and manage HTN in the inpatient setting including the common presence of physiologic conditions, which are associated with transient BP elevations (i.e., pain or anxiety), non-standard approaches to BP measurement, a lack of clarity regarding appropriate diagnostic and therapeutic thresholds, and marginal outcome data. The purpose of this review is to highlight the issues and challenges surrounding BP monitoring, assessment of elevated BPs, and the diagnosis of HTN in hospitalized children. Extrapolating from currently available clinical practice guidelines and utilizing the best data available, we aim to provide guidelines regarding evaluation and treatment of elevated BP in hospitalized children.

Evaluation of the safety and efficacy of metoprolol infusion for children and adolescents with hypertensive crises: a retrospective case series

BACKGROUND

Acute severe hypertension occurs infrequently in pediatric patients and, consequently, data on the efficacy and safety of most antihypertensive agents, as well as the adverse events associated with these agents, are very limited in this population. In this case series, we evaluated the use of metoprolol infusion in children with hypertensive emergencies.

METHODS

The study population comprised children younger than 18 years who had been admitted to the pediatric intensive care unit at King Abdullah University Hospital with blood pressure above the 99th percentile for age, height, and sex and who were symptomatic at the time of presentation. Metoprolol was given as an infusion at a dose of 1-5 mcg/kg/min. The rate of decrease in blood pressure, side effects from the medication, and outcome were assessed.

RESULTS

Thirteen patients ranging in age from 2 months to 16 years were included in this study. The initial mean blood pressure was 23-75 mmHg above the 99th percentile for age, height, and sex. Metoprolol was initiated at a dose of 0.5 mcg/kg/min and titrated according to the target blood pressure to a maximum of 5 mcg/kg/min. Mean blood pressure fell by an average of 12.3, 20.4, and 27.1% at 1, 8, and 24 h, respectively, which is consistent with findings on the use of other intravenous medications reported in published studies. The heart rate did not decrease below the normal range for age. There were no significant side effects of the metoprolol infusion. All patients were discharged home with no neurological sequelae secondary to their hypertension.

CONCLUSION

An infusion of metoprolol for a hypertensive emergency is a safe and effective treatment for pediatric patients.

Evaluation and treatment of hypertensive crises in children

Hypertensive crises in children are medical emergencies that must be identified, evaluated, and treated promptly and appropriately to prevent end-organ injury and even death. Treatment in the acute setting typically includes continuous intravenous antihypertensive medications with monitoring in the intensive care unit setting. Medications commonly used to treat severe hypertension have been poorly studied in children. Dosing guidelines are available, although few pediatric-specific trials have been conducted to facilitate evidence-based therapy. Regardless of what medication is used, blood pressure should be lowered gradually to allow for accommodation of autoregulatory mechanisms and to prevent cerebral ischemia. Determining the underlying cause of the blood pressure elevation may be helpful in guiding therapy.

Therapy of acute hypertension in hospitalized children and adolescents

Acute hypertension (HTN) in hospitalized children and adolescents occurs relatively frequently, and in some cases, if not recognized and treated promptly, it can lead to hypertensive crisis with potentially significant morbidity and mortality. In contrast to adults, where acute HTN is most likely due to uncontrolled primary HTN, children and adolescents with acute HTN are more likely to have secondary HTN. This review will briefly cover evaluation of acute HTN and various age-specific etiologies of secondary HTN and provide more in-depth discussion on treatment targets, potential risks of acute HTN therapy, and available pediatric data on intravenous and oral antihypertensive agents, and it proposes treatment schema including unique therapy of specific secondary HTN scenarios.

Old habits die hard: a nationwide utilization study of short-acting nifedipine in Taiwan

BACKGROUND

To investigate the nationwide trend of ambulatory prescriptions of short-acting nifedipine on a PRN (pro re nata) order over a fifteen-year period in Taiwan.

METHODS

The systematic sampling claims datasets (0.2% sampling ratio) of ambulatory care visits within Taiwan's National Health Insurance from 1997 to 2011 were analyzed. The prescriptions of short-acting capsule-form nifedipine on a PRN order were stratified by the patient's age, the prescribing physician's specialty, and the setting of healthcare facility for each year.

RESULTS

During the study period, 8,189,681 visits were analyzed. While the utilization rate of calcium channel blockers changed with time from 2.8% (13,767/489,636) in 1997 to 5.1% (31,349/614,719) in 2011, that of short-acting nifedipine were from 1.0% (n = 5,070) to 0.2% (n = 1,246). However, short-acting capsule-form nifedipine on a PRN order still existed (from 447 prescriptions in 1997 to 784 in 2011). More than one half of these PRN nifedipines were prescribed by the internists and to the elderly patients; almost four-fifths of PRN nifedipines were prescribed during non-emergent consultations.

CONCLUSION

The physicians in Taiwan still had the habit of prescribing short-acting nifedipines for PRN use. The reason for such practices and the impact on patients' health deserve attention.

Evaluation and management of pediatric hypertensive crises: hypertensive urgency and hypertensive emergencies

Hypertension (HTN) in the pediatric population is estimated to have a world-wide prevalence of 2%–5%. As with adults, pediatric patients with HTN can present with hypertensive crises include hypertensive urgency and hypertensive emergencies. However, pediatric blood pressure problems have a greater chance of being from secondary causes of HTN, as opposed to primary HTN, than in adults. Thorough evaluation of a child with a hypertensive emergency includes accurate blood pressure readings, complete and focused symptom history, and appropriate past medical, surgical, and family history. Physical exam should include height, weight, four-limb blood pressures, a general overall examination and especially detailed cardiovascular and neurological examinations, including fundoscopic examination. Initial work-up should typically include electrocardiography, chest X-ray, serum chemistries, complete blood count, and urinalysis. Initial management of hypertensive emergencies generally includes the use of intravenous or oral antihypertensive medications, as well as appropriate, typically outpatient, follow-up. Emergency department goals for hypertensive crises are to (1) safely lower blood pressure, and (2) treat/minimize acute end organ damage, while (3) identifying underlying etiology. Intravenous antihypertensive medications are the treatment modality of choice for hypertensive emergencies with the goal of reducing systolic blood pressure by 25% of the original value over an 8-hour period.

Hypertensive crisis in children

Hypertensive crisis is rare in children and is usually secondary to an underlying disease. There is strong evidence that the renin-angiotensin system plays an important role in the genesis of hypertensive crisis. An important principle in the management of children with hypertensive crisis is to determine if severe hypertension is chronic, acute, or acute-on-chronic. When it is associated with signs of end-organ damage such as encephalopathy, congestive cardiac failure or renal failure, there is an emergent need to lower blood pressures to 25-30% of the original value and then accomplish a gradual reduction in blood pressure. Precipitous drops in blood pressure can result in impairment of perfusion of vital organs. Medications commonly used to treat hypertensive crisis in children are nicardipine, labetalol and sodium nitroprusside. In this review, we discuss the pathophysiology, differential diagnosis and recent developments in management of hypertensive crisis in children.

Characterization of a unique dihydropyrimidinone, ethyl 4-(4'-heptanoyloxyphenyl)-6-methyl-3,4-dihydropyrimidin-2-one-5-carboxylate, as an effective antithrombotic agent in a rat experimental model

OBJECTIVES

To evaluate the potential of a novel dihydropyrimidinone, ethyl 4-(4'-heptanoyloxyphenyl)-6-methyl-3,4-dihydropyrimidin-2-one-5-carboxylate (H-DHPM), as a calcium channel blocker, endowed with the ability to inhibit platelet aggregation effectively.

METHODS

In-vitro and in-vivo studies were conducted for the determination of antiplatelet activity using adenosine diphosphate (ADP), collagen or thrombin as inducers. Calcium channel blocking activity and nitric oxide synthase (NOS) activity were monitored. Lipopolysaccharide (LPS)-mediated prothrombotic conditions were developed in rats to study the efficacy of H-DHPM to suitably modulate the inflammatory mediators such as inducible NOS (iNOS) and tissue factor. The cGMP level and endothelial NOS (eNOS) expression were checked in aortic homogenate of LPS-challenged rats pretreated with H-DHPM. The effect of H-DHPM on FeCl(3) -induced thrombus formation in rats was examined.

KEY FINDINGS

The concentrations of H-DHPM required to give 50% inhibition (IC50) of in-vitro platelet aggregation induced by ADP, collagen or thrombin were 98.2±2.1, 74.5±2.3 and 180.7±3.4µm, respectively. H-DHPM at a dose of 52.0±0.02mg/kg (133µmol/kg) was found to optimally inhibit ADP-induced platelet aggregation in-vivo. The level of nitric oxide was found to be up to 9±0.08-fold in H-DHPM-treated platelets in-vitro and 8.2±0.05-fold in H-DHPM-pretreated rat platelets in-vivo compared with control. OH-DHPM, the parent compound was found to be ineffective both in-vitro and in-vivo. H-DHPM-pretreated rats were able to resist significantly the prothrombotic changes caused by LPS by blunting the expression of iNOS, tissue factor and diminishing the increased level of cGMP to normal. H-DHPM enhanced the eNOS expression in aorta of rats treated with LPS. H-DHPM displayed synergy with antiplatelet activity of aspirin even at lower doses. H-DHPM was found to inhibit the LPS-induced platelet aggregation in younger as well as older rats. H-DHPM exhibited the ability to markedly decrease FeCl(3) -induced thrombus formation in rats.

CONCLUSIONS

H-DHPM has the attributes of a promising potent antiplatelet candidate molecule that should attract further study. H-DHPM displayed antiplatelet activity both in vivo and in vitro, which was due partially by lowering the intraplatelet calcium concentration.

Isradipine for treatment of acute hypertension in hospitalized children and adolescents

Severe acute hypertension in pediatric patients requires prompt and controlled blood pressure (BP) reduction to prevent end-organ damage. The authors aimed to examine the efficacy and safety of isradipine, an orally administered second-generation dihydropyridine calcium channel blocker, for treatment of acute hypertension in hospitalized pediatric patients. A retrospective analysis of 391 doses of isradipine administered to 282 patients (58% boys) with acute hypertension and median age of 12.8 years (range, 0.1-21.9) was performed. Primary diagnoses included renal disease (n=154), malignancy (45), nonrenal transplant (37), neurologic disease (21), and other (25). The decrease in systolic BP was 16.3%±11.6% (mean ± SD) and diastolic BP was 24.2%±17.2%. BPs were significantly lower in all age groups and in all diagnosis categories following isradipine administration. The decrease in BP was the highest in children younger than 2 years. The mean increase in pulse after a dose was 7±17 beats per minute. Forty adverse events were reported in 33 patients, with emesis and nausea being the most common; 5 of these events were hypotension. The authors conclude that isradipine effectively reduces BP in a wide variety of hospitalized children and adolescents with acute hypertension. A lower initial dose of 0.05 mg/kg may be appropriate in children younger than 2 years.

The management of hypertensive emergencies in children after stem cell transplantation

AIM OF THE REVIEW

This work presents a short overview on the available data about drugs that are currently used to treat hypertensive emergencies in children with a focus on incidents after stem cell transplantation. It shows that the pediatric use of all hypotensive agents appears to be mainly based on personal experience of the attending physicians rather than on convincing clinical trials.

METHOD

A literature search was performed in MEDLINE, through PubMed, using the medical subject headings (MeSH) hypertensive emergencies, nifedipine, nicardipine, and children. Further articles were identified by checking cross-references of articles and books.

RESULTS

Hypertensive emergencies in children after stem cell transplantation usually have a renal etiology, because of the treatment with the calcineurin inhibitors cyclosporine and tacrolimus. In these severe cases an immediate action is necessary to avoid possible appearance or exacerbation of endorgan damage. Because of their mechanism of action and a potential nephroprotective effect calcium channel blockers may be particularly suitable in cases of hypertensive emergencies. An intravenous application of nifedipine may compensate the difficulties of accurate dosing, but keeping in mind possible severe side effects and the lack of published experience its use in children is at least questionable. Nicardipine appears to be the hypotensive agent of first choice. In adults, the treatment of hypertensive emergencies with intravenous nicardipine is well-documented, but for an evaluation of safety in pediatric use, the published studies and case reports appear to be barely adequate.

CONCLUSION

The actual treatment approaches vary widely, demonstrating the lack of hard science on which current treatment of hypertensive emergencies in children is based. The hypotensive agent for the individual situation should be chosen considering the properties, side effects, the limited experiences with its use and the patient's anamnesis.

Effects of antihypertensive drugs on blood pressure and proteinuria in childhood

BACKGROUND

Historically, there have been few drug trials for antihypertensive treatment in childhood and recommendations have been extrapolated from data obtained in adulthood. During the last decade an increased awareness of the risks of childhood hypertension stimulated clinical trials of antihypertensive agents in children.

OBJECTIVE

The aim of this article is to systematically review the studies published between 1995 and 2006 that deal with the effect of antihypertensive drugs on childhood hypertension or proteinuria.

METHODS

Medline, Current Contents, personal files and reference lists were used as data sources.

RESULTS

Fifty-two out of 79 initially found reports were excluded. Consequently 27 articles were retained for the final analysis. The blood pressure reduction was similar with angiotensin-converting enzyme inhibitors (10.7/8.1 mmHg), angiotensin II receptor antagonists (10.5/6.9 mmHg) and calcium-channel blockers (9.3/7.2 mmHg). In addition angiotensin-converting enzyme inhibitors (by 49%) and angiotensin II receptor antagonists (by 59%) significantly reduced pathological proteinuria.

CONCLUSIONS

The blood pressure reduction of angiotensin-converting enzyme inhibitors, angiotensin II receptor antagonists and calcium-channel blockers is almost identical. In children with pathological proteinuria angiotensin-converting enzyme inhibitors or angiotensin II antagonists are superior to calcium-channel blockers.

Are One or Two Dangerous? Calcium Channel Blocker Exposure in Toddlers

Unintentional pediatric ingestions of calcium channel blockers are increasing in frequency due to increased use of this antihypertensive class. Potential toxic effects include severe refractory hypotension and death; however, the true toxicity of unintentional pediatric ingestions of 1-2 pills is poorly defined. A literature review was conducted to more closely determine toxic and lethal dosages of calcium channel blockers in the pediatric population under 6 years of age. Results indicate that, although most accidental pediatric ingestions are asymptomatic, a small number do result in cardiovascular instability or even death. The dihydropyridines, particularly nifedipine, and the phenylalkylamine verapamil are most often implicated in symptomatic ingestions. There are no adequate data to identify which children are predisposed to illness, or to determine cutoffs for toxic dosages. However, ingestions of only one pill have been documented to cause severe symptoms, including death. Thus, emergency evaluation to assess potential toxicity is necessary, and gastrointestinal decontamination and in-hospital observation of at least 6 h after toxic ingestion for regular release medications, and 12-24 h after toxic ingestion for sustained release medications is recommended for all cases of unintentional calcium channel blocker ingestion in children younger than 6 years of age.

A review of calcium channel antagonists in the treatment of pediatric hypertension

All children aged > or = 3 years should have an annual blood pressure (BP) measurement taken during a routine physical examination. Physicians should become familiar with recommended pediatric normative BP tables. BP above the 95th percentile may require drug therapy. There are several categories of antihypertensives available to the clinician. Calcium channel antagonists (CCAs) are a class of drugs that exert their antihypertensive effect by inhibiting the influx of calcium ions across the cell membranes. This results in dilatation of peripheral arterioles. When given orally, CCAs are metabolised in the liver by cytochrome P450 (CYP) enzyme CYP3A4; hence, some CCAs will affect the half-life of drugs that share this enzyme system for their metabolism. CCAs can be safely used in children with renal insufficiency or failure and as a general rule there is no need to modify drug dosage in this population. CCAs are generally well tolerated; most adverse effects appear to be dose related. Headache, flushing, gastrointestinal upset, and edema of the lower extremities are the most common symptoms reported with the use of CCAs. Pediatric data regarding safety and efficacy of CCAs have mostly been obtained from retrospective analyses. Extended-release nifedipine and amlodipine are the two most commonly used oral CCAs in the management of pediatric hypertension. These drugs can be given once a day, although many children require twice-daily administration. Extended-release nifedipine has to be swallowed whole; hence, its use in younger children who cannot swallow pills is limited. Amlodipine can be made into a solution without compromising its long duration of action; therefore, it is the CCA of choice for very young children. Oral short-acting nifedipine and intravenous nicardipine are safe and effective CCAs for the management of hypertensive crisis in children. Short-acting nifedipine can cause unpredictable changes in BP; hence, it should be used cautiously and in low doses. Intravenous nicardipine has a rapid onset of action and a short half-life. Intravenous infusion of nicardipine can be titrated for effective control of BP. Intravenous nicardipine has been used safely in hospitalized children and newborns for the management of hypertensive crisis, and for controlled hypotension during surgery. CCAs are a class of antihypertensives that are safe and effective in pediatric patients. They have relatively few adverse effects and are well tolerated by children. This article reviews CCAs as antihypertensives in the management of pediatric hypertension.

Paediatric formulations—Getting to the heart of the problem

Many medicines prescribed for children are unlicensed. Solid dosage forms present problems as children have difficulty swallowing whole tablets or capsules. When medicines are not licensed for children, it is unlikely that there will be a suitable, licensed liquid formulation and so extemporaneous liquid preparations (prepared at the dispensary or by GMP 'special' manufacturers) are often used. This study looked at a list of medicines commonly prescribed for children with cardiovascular conditions in an English specialist paediatric hospital and classified them according to licensed status and available formulations. As expected, most medicines used for children with cardiovascular problems were unlicensed and where this was the case, usually only 'special' liquids or extemporaneous preparations were available. Problems linked with formulations highlighted in this therapeutic category were: problems in dosing accuracy and unknown bioavailability of extemporaneous products, the use of potentially toxic excipients, and lack of access to modified release preparations for children. These problems are likely to extend to other paediatric therapeutic areas. There is currently a large, unmet need to improve formulations of commonly used paediatric medicines, both through licensing and standardising the production of extemporaneous and 'special' formulations. It is expected that the awaited European regulation will help to meet some of those needs.

Ventricular arrhythmia following short-acting nifedipine administration

Short-acting nifedipine is still advocated for use in children with severe hypertension, but is no longer recommended for use in adults because of adverse effects from rapid blood pressure reduction. A 19 year-old adolescent with symptomatic, severe hypertension (blood pressure 180/120) received 10 mg of short-acting nifedipine sublingually for blood pressure reduction. Within minutes after the dose, the patient complained of palpitations. Tachycardia (heart rate 100 beats per minute) and bigeminy were noted on the cardiac monitor. The bigeminy resolved but premature ventricular contractions were noted for the duration of her hospital stay. We hypothesize that reflex sympathetic activation following an abrupt drop in blood pressure may cause arrhythmias because of elevated catecholamine levels. Given this, it may be more appropriate to treat severe hypertension in children with intravenous antihypertensive agents that can be titrated to produce controlled reductions in blood pressure.

The assessment and management of hypertensive emergencies and urgencies in children

Although the prevalence of hypertension in the pediatric population is estimated at only 1% to 2%, hypertensive urgencies and emergencies may be encountered in the emergency department. Efficient management of these children is of utmost importance to avoid some of the life-threatening complications associated with hypertension and its treatment. This article serves to review some of the important aspects of pediatric hypertensive emergencies, including diagnosis, emergency department investigations, and pharmacologic management.

Advances in the pathogenesis and management of hypertensive crisis

PURPOSE OF REVIEW

This review summarizes recent insights into to the pathophysiology of hypertensive crisis with the emphasis on newly discovered molecular mechanisms underlying hypertension and also updates current therapeutic options for treating hypertensive crisis in children.

RECENT FINDINGS

There is growing evidence that the renin-angiotensin system plays a key role in the pathogenesis of hypertensive crises. Recent studies have shown that oxidative stress and factors affecting endothelial function are also important. Treatment of hypertensive crisis still focuses on lowering of blood pressure in an expeditious but safe manner. There is growing experience with IV nicardipine, which is becoming a viable alternative to sodium nitroprusside in children.

SUMMARY

Current knowledge of hypertensive crisis emphasizes the need for additional animal and translational studies with the goal of identifying the underlying molecular pathogenesis and developing new therapies to optimize future treatment of hypertensive emergencies.

Safety of short-acting nifedipine in children with severe hypertension

Short-acting nifedipine has been abandoned as a treatment for severe hypertension in adults as a result of significant adverse effects. Despite this, it remains a popular choice for the treatment of severe hypertension in children. However, recent publications describing adverse effects of short-acting nifedipine in children similar to those reported in adults, have prompted some experts to question the continued use of this agent in children. In this review, available data on the pharmacology, clinical efficacy and safety of short-acting nifedipine are reviewed, and the advisability of using short-acting nifedipine is reassessed. Although low (< 0.25 mg/kg) doses of short-acting nifedipine may be safe in some hypertensive children, alternative agents that produce more controlled reductions in blood pressure, and that are easier to accurately dose and administer, should probably be chosen for the majority of children with severe hypertension.

Systemic Hypertension: Management in Children and Adolescents

Recognition of systemic hypertension in children and adolescents requires careful blood pressure measurement using proper technique to compare with appropriate normative data. Selected use of ambulatory blood pressure monitoring can identify children with "white coat" hypertension, thus avoiding unnecessary diagnostic testing and treatment in these children. Nonpharmacologic therapies including dietary sodium restriction, weight loss, and exercise may benefit children and adolescents with borderline hypertension and mild essential hypertension. These therapies may be important adjunctive agents in children requiring antihypertensive therapy as well. Historically, pharmacologic management of hypertension in children has been limited by a lack of controlled studies and age-appropriate formulations. Recent clinical trials have provided new information regarding a number of antihypertensive agents in this age group.

Pediatric hypertension 2001

During the past decade, there has been a surge of interest in childhood and adolescent hypertension. The current review summarizes work published during the past year in the following areas: prenatal and early postnatal causes of hypertension; new information on the genetics of childhood hypertension; the relation of obesity, insulin resistance, and diabetes to hypertension; the use of ambulatory blood pressure monitoring to evaluate childhood hypertension; and advances in drug therapy for children with hypertension. The information obtained during the past year has improved our understanding of the pathogenesis, diagnosis, and treatment of childhood hypertension.

Pediatric hypertension: recent literature

This article reviews selected recent literature specifically concerning pediatric hypertension, much of which has focused on measurement and monitoring of blood pressure, as well as on evaluating antihypertensive medications. Normative data for blood pressure in children have been widely available for some time, based upon seated in-office measurements. In recent years, ambulatory blood pressure monitoring (ABPM), facilitated by user-friendly instrumentation, has become more commonplace, though norms are not based on large populations. However, ABPM has important uses in assessing blood pressure as well as in monitoring antihypertensive. This review discusses issues involved in determining blood pressure, as well as the utility of ABPM in several situations. Recent developments concerning pediatric antihypertensive therapy are considered, as well as new information relevant to the diagnosis, course and treatment of hypertension in children and adolescents.