Treatment of pediatric hypertension

β-blocker therapy for infantile hemangioma

INTRODUCTION

Fifteen percent of proliferating infantile hemangioma (IH) require intervention because of the threat to function or life, ulceration, or tissue distortion. Propranolol is the mainstay treatment for problematic proliferating IH. Other β-blockers and angiotensin-converting enzyme (ACE) inhibitors have been explored as alternative treatments.

AREAS COVERED

The demonstration of a hemogenic endothelium origin of IH, with a neural crest phenotype and multi-lineage differentiation capacity, regulated by the renin-angiotensin system, underscores its programmed biologic behavior and accelerated involution induced by propranolol, other β-blockers and ACE inhibitors. We review the indications, dosing regimens, duration of treatment, efficacy and adverse effects of propranolol, and therapeutic alternatives including oral atenolol, acebutolol, nadolol, intralesional propranolol injections, topical propranolol and timolol, and oral captopril.

EXPERT OPINION

Improved understanding of the biology of IH provides insights into the mechanism of action underscoring its accelerated involution induced by propranolol, other β-blockers and ACE inhibitors. More research is required to understand the optimal dosing and duration, efficacy and safety of these alternative therapies. Recent demonstration of propranolol's actions mediated by non-β-adrenergic isomer R-propranolol on stem cells, offers an immense opportunity to harness the efficacy of β-blockers to induce accelerated involution of IH, while mitigating their β-adrenergic receptor-mediated adverse effects.

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.

Targeting renin-angiotensin system in malignant hypertension in atypical hemolytic uremic syndrome

Hypertension is common in hemolytic uremic syndrome (HUS) and often difficult to control. Local renin-angiotensin activation is believed to be an important part of thrombotic microangiopathy, leading to a vicious cycle of progressive renal injury and intractable hypertension. This has been demonstrated in vitro via enhanced tissue factor expression on glomerular endothelial cells which is enhanced by angiotensin II. We report two pediatric cases of atypical HUS with severe refractory malignant hypertension, in which we targeted the renin-angiotensin system by using intravenous (IV) enalaprilat, oral aliskiren, and oral enalapril with quick and dramatic response of blood pressure. Both drugs, aliskiren and IV enalaprilat, were effective in controlling hypertension refractory to multiple antihypertensive medications. These appear to be promising alternatives in the treatment of severe atypical HUS-induced hypertension and hypertensive emergency.

Antihypertensive Therapy in Females: A Clinical Review Across the Lifespan

Hypertension affects one-third of all females in the United States, with the prevalence increasing over a female's lifespan. The approach to treating females with hypertension varies depending on a female's age, race, comorbidities, and whether she is of child-bearing age or pregnant. It is important to factor in the safety and effectiveness of antihypertensive medications across these populations of females. Blood pressure target goals are the same in females as in males regardless of comorbidities or stage of life, with the exception of those females who are pregnant. Recommendations for antihypertensive medication do not differ between females and males based on disease state or stage of life, with the exception of females who are pregnant, breastfeeding, or of child-bearing age. Multiple guidelines recommend avoiding renin-angiotensin system blockers during pregnancy and suggest balancing the risk versus benefit in females of child-bearing age. Further, multiple guidelines provide race-based therapy recommendations for the use of calcium channel blockers and thiazide diuretics in black versus nonblack patients, irrespective of sex. Future research is needed to evaluate whether there are sex differences relative to blood pressure and cardiovascular event-lowering relative to specific antihypertensive medications with a focus on pharmacogenomic differences.

Therapeutic options for the treatment of hypertension in children and adolescents

Primary hypertension in children is increasing in prevalence with many cases likely going undiagnosed. The prevalence is currently estimated at between 3%-5% in the United States and may be higher in certain ethnic groups. Primary hypertension, once felt to be rare in children, is now considered to be about five times more common than secondary hypertension. This review provides information to guide physicians through an organized approach to: 1) screening children and adolescents for hypertension during routine visits; 2) using normative percentile data for diagnosis and classification; 3) performing a clinical evaluation to identify the presence of co-morbidities; 4) initiating a plan of care including subsequent follow-up blood pressure measurements, therapeutic lifestyle changes and pharmacologic therapies.

Drug treatment of hypertensive crisis in children

Hypertensive crisis is a relatively rare event and is associated with significant morbidity and mortality in adults and pediatric patients alike. Rapid, safe, and effective treatment is imperative to alleviate immediate presenting clinical symptoms, prevent devastating morbidity, preserve long-term quality of life, and prevent mortality. Many medications in the hypertensive crisis arsenal have been used for nearly half a century. Nearly all treatment options have been utilized in children for decades, yet reliable data and sound clinical literature remain elusive. Every agent considered to be a first-line, second-line, or adjunctive option has yet to be evaluated in a randomized controlled trial in pediatric patients. With a paucity of clinical data to form evidence-based decisions, the clinician must rely entirely on the extrapolation from adult data and small retrospective studies, case series, and case reports of medication use in pediatric patients. Although more research in the treatment of pediatric hypertensive crisis is desperately needed, current practice demands a sharp knowledge of the pediatric clinical literature and pharmacology in this area as an essential tool to consistently improve patient outcomes with respect to morbidity and mortality.

Safety and efficacy of intravenous labetalol for hypertensive crisis in infants and small children

OBJECTIVE

To determine the efficacy and safety of labetalol for hypertensive crisis in children ≤ 24 months of age.

DESIGN

Retrospective chart review. Statistical analysis utilized analysis of variance for continuous data, chi-square tests for nominal data, and linear regression.

SETTING

A 737-bed pediatric teaching institution.

PATIENTS

Twenty-seven patients ≤ 24 months of age were treated with 37 intravenous infusions of labetalol, nicardipine, or nitroprusside for hypertensive crisis or hypertensive urgency.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary end point consisted of time to 20% reduction in systolic blood pressure. Primary safety end points measured the prevalence of deleterious effects of labetalol. Continuous infusion of labetalol reduced mean systolic blood pressure by at least 20% in < 8 hrs. This effect was similar to nicardipine and nitroprusside infusions. The reported side effects were similar in each group. Patients receiving labetalol and presenting with ischemic or traumatic brain injury were likely to develop hypotension requiring infusion discontinuation.

CONCLUSIONS

Continuous intravenous labetalol infusion is efficacious for treatment of hypertensive crisis in children ≤ 24 months of age. Aside from patients presenting with ischemic or traumatic brain injury, labetalol was safe to use in this population for hypertensive emergencies and had a satisfactory adverse effect profile. Labetalol may reach dose saturation at a much lower dose in young children in comparison to adults. Clinicians should use caution when initiating labetalol infusions in young patients with brain injury.

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.

Hypertensive emergency associated with thoracoabdominal aneurysm: case report and review

OBJECTIVE

To provide a description and thorough discussion of the diagnostic considerations for a rare case of malignant hypertension and aortic aneurysm in a pediatric patient.

DESIGN

Case report.

SETTING

A university pediatric intensive care unit.

SUBJECT

A young child with a hypertensive crisis and a thoracoabdominal false aortic aneurysm.

INTERVENTIONS

The child required urgent surgical intervention to resect the aneurysm and aggressive medical therapy in the pediatric intensive care unit to treat the underlying hypertension.

CONCLUSIONS

Hypertensive emergencies and aortic aneurysms are unusual but potentially lethal entities in pediatric patients, requiring a high index of suspicion, prompt initiation of medical therapy, and urgent surgical consultation.

Bioavailability of a pediatric amlodipine suspension

Currently, a suspension of crushed tablets of amlodidpine is widely used in children with hypertension without knowledge of its bioavailability. A comparative bioavailability study of a tablet and suspension formulation of amlodipine was completed in 20 healthy adult volunteers. Bioequivalence of the suspension was not different from the tablets. These results support the use of the suspension in children who cannot take the tablet.

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.

A double-blind, placebo-controlled, dose-response study of the effectiveness and safety of enalapril for children with hypertension

Despite widespread use to treat childhood hypertension, enalapril has never been studied systematically to determine effectiveness, dose response, and safety in a pediatric population. This study was conducted prospectively in 110 hypertensive children ages 6 to 16 years in two sequential phases. The primary outcome variable for both phases of the study was trough (24-h postdose) sitting diastolic blood pressure. The primary objective of the first phase of the study was to determine whether enalapril lowered blood pressure in children in a dose-dependent manner. During a 2-week, double-blind, randomized, dose-response period, patients were stratified by weight (< 50 kg or > or = 50 kg), then assigned to one of three dosing groups: low(0.625 or 1.25 mg), middle (2.5 or 5 mg), or high dose (20 or 40 mg). Reduction in blood pressure was examined as a function of dose ratio (1:4:32) and on a weight-adjusted basis. On completion of the dose-response phase of the study, patients entered a 2-week, double-blind, randomized withdrawal to either enalapril or placebo. Antihypertensive effectiveness, defined as the difference in sitting diastolic blood pressure between the placebo and enalapril groups, was determined. Adverse events were carefully recorded throughout the study. The dose-response relationship for enalapril had a negative slope and was linear over the chosen dosing range, suggesting that larger doses of enalapril were associated with a greater reduction in blood pressure. Randomized withdrawal to active drug orplacebo confirmed the antihypertensive effectiveness of enalapril in the middle- and high-dose groups. The antihypertensive effect of enalapril was maintained across age, gender, race, and Tanner stage. Enalapril appears to be an effective and generally well-tolerated antihypertensive agent in children ages 6 to 16 years. An initial dose of 2.5 mg in children weighing < 50 kg and 5 mg in children weighing > 50 kg (mean = 0.08 mg/kg) administered once daily effectively lowered blood pressure within 2 weeks in most patients. Blood pressure was reduced in a dose-dependent fashion, with larger doses resulting in a greater reduction.

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.

What's new in pediatric hypertension?

Research activities in the field of pediatric hypertension have been increasing in recent years, leading to important new findings in the epidemiology, diagnosis, and treatment of hypertension in children. This review summarizes recent work in these areas, focusing on the epidemic of obesity-related hypertension in children, advances in the drug therapy of childhood hypertension, and the increasing use of ambulatory blood pressure monitoring in evaluation of hypertensive children. Each of these three areas will no doubt develop further over the years ahead, resulting in further advances in the field of childhood hypertension.

Risk factors for cardiovascular disease in children on maintenance dialysis

Cardiovascular disease mortality is high in children on maintenance dialysis, accounting for about 25% of patient deaths. Cardiovascular-related mortality rates for children on dialysis are higher than for children with successful kidney transplants. Data on the long-term consequences of risk factors for cardiovascular disease are lacking for pediatric end-stage renal disease patients. This article reviews pediatric data pertaining to the following risk factors: anemia, hypertension, hyperlipidemia, left ventricular hypertrophy, abnormal calcium-phosphorus metabolism, and hyperhomocysteinemia. The potential relationship of end-stage renal disease to the etiology of several functional disorders of the cardiovascular system is discussed. Clinical studies are needed to assess the prevalence of cardiovascular disease and of cardiovascular disease risk factors in the pediatric end-stage renal disease population. Possible preventive and therapeutic guidelines need to be developed for at-risk children on maintenance dialysis.

Enteral suspension of nifedipine for neonates. Part 1. Formulation of nifedipine suspension for hospital use

OBJECTIVE

To formulate an oral suspension of nifedipine for paediatric use and to assess its content uniformity as well as the microbiological and physical stabilities of the hypromellose solution that was used in the formulation.

METHOD

Six concentrations (0.5-3.0%) of hypromellose colloids and water as a blank were compounded with nifedipine, both as a powder and as crushed tablets, to a concentration of 1 mg/mL. Four different screening tests were used to find the most homogenous and dose-accurate combination. First, nifedipine suspensions were stored in vials for one month and visual homogenity of the redispersed suspensions was observed. Second, the homogenity of the suspensions was studied by measuring the nifedipine concentration from upper, middle and lower parts of the redispersed suspension. Next, the nifedipine concentration was measured from the suspensions immediately, 1 min and 2 min after shaking to ensure dose accuracy during the administration period. Finally, suspensions were packaged into oral disposable syringes and nifedipine concentrations were determined after one month of storage. Content uniformity of the packaged single-dose syringe suspensions was studied according to a method established by the European Pharmacopoeia. Microbiological stability, density, pH, osmolality, viscosity and surface tension of the hypromellose solution were studied over a 12-month storage period.

RESULTS

From the results of the screening tests of hypromellose solution, 1.0% hypromellose was chosen as the vehicle for nifedipine enteral suspensions, made from both crushed tablets and nifedipine powder. Nifedipine suspensions made from hypromellose 1.0% were easiest to redisperse as a homogenous solution, and it also appeared best on visual inspection. The content uniformity of the suspension complied with the test recommended by the European Pharmacopoeia. The 1.0% hypromellose solution was found to be microbiologically stable for 6 months and physically stable for 12 months.