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

Calcium Channel Blocker Overdose Causes Acute Respiratory Distress Syndrome and Acute Kidney Injury in a 15-Year-Old Female

Calcium channel blockers (CCBs) are among the most commonly prescribed cardiovascular medications in the adult population. Approximately 20% of adults with hypertension in the United States are prescribed dihydropyridine calcium channel blockers. Similarly, in the pediatric population, CCBs such as nifedipine and amlodipine are frequently prescribed in the non-emergent management of hypertension in children and adolescents. Despite the prevalence of CCB usage, the available literature on the management of calcium channel blocker toxicity in the pediatric population remains scarce. In the absence of formal guidelines, the management of CCB overdoses comes from case reports. This case identifies a 15-year-old Hispanic female who developed acute respiratory distress syndrome (ARDS) and acute kidney injury (AKI) after an overdose of amlodipine. Our patient presented with profound, refractory hypotension requiring substantial inotropic support. She subsequently developed significant dyspnea, desaturating into the 80s with radiological evidence of ARDS requiring endotracheal intubation. After aggressive diuresis and electrolyte replacement, along with inotropic agents to maintain adequate blood pressure, our patient began to make significant clinical progress. With continued improvement and resolution of her AKI and ARDS, she was successfully weaned off ventilatory support and all infusions. Our patient was deemed medically appropriate for discharge 10 days after the initial presentation and was admitted to an inpatient psychiatric unit. Calcium channel blocker toxicity can pose considerable risks, as was seen with our patient. Prompt recognition and judicious management of CCB overdoses can mitigate associated morbidity and mortality, resulting in favorable outcomes for patients. The intention behind documenting this case is to contribute to the limited literature on the successful management of calcium channel blocker poisoning in the pediatric population.

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.

Synthesis of Dihydropyrimidines: Isosteres of Nifedipine and Evaluation of Their Calcium Channel Blocking Efficiency

Hypertension and cardiovascular diseases related to it remain the leading medical challenges globally. Several drugs have been synthesized and commercialized to manage hypertension. Some of these drugs have a dihydropyrimidine skeleton structure, act as efficient calcium channel blockers, and affect the calcium ions' intake in vascular smooth muscle, hence managing hypertension. The synthesis of such moieties is crucial, and documenting their structure-activity relationship, their evolved and advanced synthetic procedures, and future opportunities in this area is currently a priority. Tremendous efforts have been made after the discovery of the Biginelli condensation reaction in the synthesis of dihydropyrimidines. From the specific selection of Biginelli adducts to the variation in the formed intermediates to achieve target compounds containing heterocylic rings, aldehydes, a variety of ketones, halogens, and many other desired functionalities, extensive studies have been carried out. Several substitutions at the C3, C4, and C5 positions of dihydropyrimidines have been explored, aiming to produce feasible derivatives with acceptable yields as well as antihypertensive activity. The current review aims to cover this requirement in detail.

Antihypertensive agents: a long way to safe drug prescribing in children

Recently updated clinical guidelines have highlighted the gaps in our understanding and management of pediatric hypertension. With increased recognition and diagnosis of pediatric hypertension, the use of antihypertensive agents is also likely to increase. Drug selection to treat hypertension in the pediatric patient population remains challenging. This is primarily due to a lack of large, well-designed pediatric safety and efficacy trials, limited understanding of pharmacokinetics in children, and unknown risk of prolonged exposure to antihypertensive therapies. With newer legislation providing financial incentives for conducting clinical trials in children, along with publication of pediatric-focused guidelines, literature available for antihypertensive agents in pediatrics has increased over the last 20 years. The objective of this article is to review the literature for safety and efficacy of commonly prescribed antihypertensive agents in pediatrics. Thus far, the most data to support use in children was found for angiotensin-converting enzyme inhibitors (ACE-I), angiotensin receptor blockers (ARB), and calcium channel blockers (CCB). Several gaps were noted in the literature, particularly for beta blockers, vasodilators, and the long-term safety profile of antihypertensive agents in children. Further clinical trials are needed to guide safe and effective prescribing in the pediatric population.

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.

The Rotavirus NSP4 Viroporin Domain is a Calcium-conducting Ion Channel

Viroporins are small virus-encoded ion channel proteins. Most viroporins are monovalent selective cation channels, with few showing the ability to conduct divalent cations, like calcium (Ca2+). Nevertheless, some viroporins are known to disrupt host cell Ca2+ homeostasis, which is critical for virus replication and pathogenesis. Rotavirus nonstructural protein 4 (NSP4) is an endoplasmic reticulum transmembrane glycoprotein that has a viroporin domain (VPD), and NSP4 viroporin activity elevates cytosolic Ca2+ in mammalian cells. The goal of this study was to demonstrate that the NSP4 VPD forms an ion channel and determine whether the channel can conduct Ca2+. Using planar lipid bilayer and liposome patch clamp electrophysiology, we show that a synthetic peptide of the NSP4 VPD has ion channel activity. The NSP4 VPD was selective for cations over anions and channel activity was observed to have both well-defined "square top" openings as well as fast current fluctuations, similar to other viroporins. Importantly, the NSP4 VPD showed similar conductance of divalent cations (Ca2+ and Ba2+) as monovalent cations (K+), but a viroporin defective mutant lacked Ca2+ conductivity. These data demonstrate that the NSP4 VPD is a Ca2+-conducting viroporin and establish the mechanism by which NSP4 disturbs host cell Ca2+ homeostasis.

Antihypertensive drug-induced angioedema causing upper airway obstruction in children

OBJECTIVE

Angioedema is a well-described complication arising from the use of antihypertensive agents in the adult population. However, its occurrence and potential for upper airway compromise in pediatrics has only been sporadically reported in the literature. Our objective is to report and review the occurrence of antihypertensive-induced angioedema in the pediatric population and the potential for airway compromise.

METHODS

Charts of 42 patients admitted to Cincinnati Children's Hospital Medical Center with the discharge diagnosis of angioedema (ICD-9 code 995.1) from January 2000 to January 2010 were reviewed. Of the 42 charts, 3 cases had angioedema induced by antihypertensive drugs and all 3 resulted in upper airway obstruction. Summary and findings of the data collected from the medical chart review included demographics, chief complaint(s), past medical history, hospital course, antihypertensive drugs used, diagnostic test(s), medical treatment, and time from onset of symptoms to resolution. In addition, a PubMed literature search using the terms angioedema and antihypertensive drugs was performed to review its occurrence in pediatrics. The previous literature case reports were compared to our cases to further characterize and emphasize the clinical features of this occurrence in children and adolescents.

RESULTS

Despite the well-known occurrence of antihypertensive drug-induced angioedema causing airway obstruction in adults, only 4 case reports have been previously published in children. At our institution, we describe 3 children who developed acute angioedema with upper airway obstruction after the chronic use of antihypertensive medications [2 drugs in the ACE inhibitor class (enalapril and lisinopril), and 1 drug in the calcium channel blocker class (CCB; amlodipine)]. In all 3 cases, the symptoms resolved within 1 week after the antihypertensive agent was discontinued.

CONCLUSION

Upper airway obstruction can occur at any age when taking antihypertensive drugs. Particular caution should be applied to ACE inhibitors and CCBs in this regard. With the increasing use of antihypertensive agents in the pediatric population, clinicians should be alert to the possibility of angioedema with upper airway obstruction as a potential lethal adverse effect.

Hypertension and CKD

Hypertension is found in more than 50% of pediatric patients with CKD. However, its prevalence varies according to the cause of CKD. It is relatively infrequent in children with structural disorders. Acquired renal disorders are associated with an increased prevalence of hypertension, similar to that of adults. Recent studies using ambulatory blood pressure monitoring indicate that children with CKD also have a high prevalence of masked hypertension. Similar to adults, long-standing and uncontrolled hypertension in children is associated with the progression of CKD and development of end-organ damage including early cardiomyopathy and premature atherosclerosis. Aggressive treatment of hypertension should be an essential part of pediatric CKD care, not just to prevent the development of symptomatic cardiovascular disease but also to delay progression of CKD. Recent findings from the European Effect of Strict Blood Pressure Control and ACE Inhibition on Progression of Chronic Renal Failure in Pediatric Patients (ESCAPE) trial have shown that the aggressive treatment of blood pressure, to below the 50th percentile, has even greater benefit in children with CKD, unlike results seen in adult studies.

Amlodipine-Induced Gingival Hyperplasia in a Child: Case Report and a Review of the Literature

Objective:

To increase awareness of amlodipine-induced gingival hyperplasia in children, as well as review whether a dose-related relationship exists.

Case Summary:

A 9-year-old girl with a past medical history of membranous nephropathy and hypertension presented with failure to thrive and inability to gain weight. She had a history of allergy to enalapril. On admission, she was found to have gingival hyperplasia. A review of her medication profile found amlodipine and azathioprine to be possible agents for this adverse reaction. The child's mother noticed this adverse effect after an increase in amlodipine dosage. We recommended substituting the angiotensin receptor blocker losartan for amlodipine; however, the nephrologist feared a cross-reactivity with enalapril and decided to continue amlodipine therapy. A follow-up call after hospital discharge revealed that the patient could no longer eat by mouth and that her gums bled upon brushing.

Discussion:

We reviewed the possible role of azathioprine in causing our patient's gingival hyperplasia. Due to the timeliness of this occurrence and the possibility of a dose-related response, we selectively reviewed the literature associated with amlodipine in children. A PubMed search and subsequent review of the literature revealed 1 study in rats that showed a relationship between amlodipine dose/plasma concentration and gingival hyperplasia. In humans, this relationship was reported with other calcium channel blockers, but not with amlodipine and not in a child. The Naranjo probability scale revealed a possible adverse reaction of gingival hyperplasia associated with amlodipine.

Conclusions:

To our knowledge, this is the first report of a possible dose-related occurrence of gingival hyperplasia in a child receiving amlodipine.

Angioedema associated with dihydropyridine calcium-channel blockers in a child with Burkitt lymphoma

PURPOSE

A case of severe macroglossia and angioedema in a child with Burkitt lymphoma who was treated with two dihydropyridine calcium-channel blockers is reported.

SUMMARY

An eight-year-old white boy arrived at the pediatric emergency department with complaints of abdominal pain and distention after an episode of mild abdominal trauma. Physical examination results were significant for diffuse abdominal tenderness and distention, with a large palpable mass in the right quadrants. Computed tomography revealed a large abdominal mass, and a biopsy confirmed a diagnosis of Burkitt lymphoma. Before initiation of chemotherapy, the child developed tumor lysis syndrome, with subsequent renal failure and cardiorespiratory compromise. Once the patient was stabilized and sedated on mechanical ventilation, tumor-directed chemotherapy was initiated, and rapid tumor regression ensued. To control episodes of hypertension, nicardipine was initiated and titrated to achieve the blood pressure goals. Three days after initiation of nicardipine therapy, the child developed facial swelling and significant, protruding macroglossia. Eight days after nicardipine initiation, a tracheotomy was required due to upper airway obstruction; at that time, the patient was converted to amlodipine administered via nasogastric tube for continued blood pressure control. The boy's macroglossia persisted for another 18 days, until a multi-disciplinary drug therapy review resulted in the discontinuation of amlodipine. Within one week of the withdrawal of amlodipine, the child's macroglossia was completely resolved.

CONCLUSION

An eight-year-old boy with Burkitt lymphoma developed severe macroglossia and angioedema when treated with nicardipine. The reaction persisted throughout treatment with amlodipine and resolved quickly after amlodipine was withdrawn.

Superior palatability of crushed lercanidipine compared with amlodipine among children

AIMS

To compare the taste of equivalent doses of pulverized amlodipine and lercanidipine, two calcium channel blockers, among children with kidney disease.

METHODS

Each child received a test dose of 1 mg of amlodipine besylate and 2 mg of lercanidipine in a single-blinded fashion. Children indicated their preference by pointing to the appropriate face on a visual analogue scale (VAS) that depicts five degrees of pleasure.

RESULTS

The VAS palatability score assigned to lercanidipine was higher than that assigned to amlodipine both in nine children 4-7 years of age (P < 0.005) and in 10 children 8-11 years of age (P < 0.005). The preference for lercanidipine was statistically significant in both girls (P < 0.02) and boys (P < 0.001) and in both children initially presented amlodipine (P < 0.005) and children initially presented lercanidipine (P < 0.005).

CONCLUSIONS

There is a lack of appropriate formulations for children prescribed drugs originally designed for adults, such as calcium channel blockers. Parents therefore crush available tablets and administer the medication mixed with solid food or a palatable drink. From the perspective of the child, the taste of pulverized lercanidipine is superior to that of pulverized amlodipine.

Pimaradienoic acid inhibits vascular contraction and induces hypotension in normotensive rats

The present investigation was designed to investigate the effect of the diterpene ent-pimara-8(14),15-dien-19-oic acid (pimaradienoic acid, PA) on smooth muscle extracellular Ca2+ influx. To this end, the effect of PA on phenylephrine- and KCl-induced increases in cytosolic calcium concentration ([Ca2+]c), measured by the variation in the ratio of fluorescence intensities (R340/380 nm) of Fura-2, was analysed. Whether bolus injection of PA could induce hypotensive responses in conscious normotensive rats was also evaluated. PA inhibited the contraction induced by phenylephrine (0.03 or 10 μmol L−1) and KCl (30 or 90 μmol L−1) in endothelium-denuded rat aortic rings in a concentration dependent manner. Pre-treatment with PA (10, 100, 200 μmol L−1) attenuated the contraction induced by CaCl2 (0.5 nmol L−1 or 2.5 μmol L−1) in denuded rat aorta exposed to Ca2+-free medium containing phenylephrine (0.1 μmol L−1) or KCl (30 μmol L−1). Interestingly, the inhibitory effect displayed by PA on CaCl2-induced contraction was more pronounced when KCl was used as the stimulant. Phenylephrine- and KCl-induced increases in [Ca2+]c were inhibited by PA. Similarly, verapamil, a Ca2+-channel blocker, also inhibited the increase in [Ca2+]c induced by either phenylephrine or KCl. Finally, bolus injection of PA (1–15 mg kg−1) produced a dose-dependent decrease in mean arterial pressure in conscious normotensive rats. The results provide the first direct evidence that PA reduces vascular contractility by reducing extracellular Ca2+ influx through smooth muscle cellular membrane, a mechanism that could mediate the hypotensive response induced by this diterpene in normotensive rats.

Nicardipine: a hypotensive dihydropyridine-type calcium antagonist with a peculiar cerebrovascular profile

Control of blood pressure protects against the development of cerebrovascular lesions, stroke, and vascular dementia (VaD). Cerebrovascular disease is increasingly recognized as a cause of cognitive impairment and dementia primarily in the elderly. Nicardipine is a dihydropyridine-type calcium channel blocker (CCB) with a peculiar cerebrovascular profile developed approximately 30 years ago. This study has reviewed the main controlled clinical studies investigating the use of nicardipine in pathologies associated with cerebrovascular injury, such as subarachnoid haemorrhage (SAH), acute stroke, and VaD. SAH is a main cerebrovascular indication of CCBs. In this indication, CCBs prevent vasospasm and improve clinical outcomes. Nimodipine represents the CCB more investigated in this indication. Former studies did not demonstrate a clear advantage of nicardipine versus nimodipine in SAH. A more recent approach using implants of nicardipine prolonged-release showed a decreased incidence of vasospasm, delayed ischemic deficits, and improved clinical outcome after severe SAH. Controlled trials have shown the effectiveness of the drug in preventing stroke. Increasing evidence suggests some benefit of some CCBs in VaD or mixed degenerative and vascular dementia. In this setting, nicardipine has been investigated in approximately 6,000 patients, with an improvement of cognitive deterioration in more than 60% of patients treated. The pronounced anti-hypertensive activity of nicardipine and its safety and effectiveness in cognitive domain suggest its reconsideration in the treatment of cognitive impairment of vascular origin as well as for reducing the risk of recurrent stroke in patients at high risk of it.

Hypertension in children with chronic kidney disease: pathophysiology and management

Arterial hypertension is very common in children with all stages of chronic kidney disease (CKD). While fluid overload and activation of the renin-angiotensin system have long been recognized as crucial pathophysiological pathways, sympathetic hyperactivation, endothelial dysfunction and chronic hyperparathyroidism have more recently been identified as important factors contributing to CKD-associated hypertension. Moreover, several drugs commonly administered in CKD, such as erythropoietin, glucocorticoids and cyclosporine A, independently raise blood pressure in a dose-dependent fashion. Because of the deleterious consequences of hypertension on the progression of renal disease and cardiovascular outcomes, an active screening approach should be adapted in patients with all stages of CKD. Before one starts antihypertensive treatment, non-pharmacological options should be explored. In hemodialysis patients a low salt diet, low dialysate sodium and stricter dialysis towards dry weight can often achieve adequate blood pressure control. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers are first-line therapy for patients with proteinuria, due to their additional anti-proteinuric properties. Diuretics are a useful alternative for non-proteinuric patients or as an add-on to renin-angiotensin system blockade. Multiple drug therapy is often needed to maintain blood pressure below the 90th percentile target, but adequate blood pressure control is essential for better renal and cardiovascular long-term outcomes.

Systemic hypertension and proteinuria in childhood chronic renal parenchymal disease: role of antihypertensive drug management

A variety of chronic kidney diseases tend to progress towards end-stage kidney disease. Progression is largely due to factors unrelated to the initial disease, including systemic hypertension and proteinuria. Drugs that block the renin-angiotensin II-aldosterone system, either ACE inhibitors or angiotensin II receptor antagonists, reduce both BP and proteinuria and appear superior to a more conventional antihypertensive treatment regimen in preventing progression to end-stage kidney disease. The most recent recommendations state that the BP goal in children with chronic kidney disease is the corresponding 90th centile for body height, age, and gender. Since satisfactory BP control is often not achieved, the mnemonic acronym DELTAREPROSI was generated to recall the following tips for the practical management of hypertension and proteinuria in childhood chronic renal parenchymal disease: DEfinition of hypertension and Low blood pressure TArget in REnal disease (90th centile calculated by means of simple formulas), potential of drugs inhibiting the REnin-angiotensin II-aldosterone system in hypertension and PROteinuria, advantages of SImplified treatment regimens and escalating the doses every SIx weeks.