Novel Use of Clevidipine for Intraoperative Blood Pressure Management in Patients With Pheochromocytoma

Pheochromocytomas are rare tumors that produce excessive epinephrine and norepinephrine, leading to multiple manifestations of catecholamine surges. Acute intraoperative hypertension during pheochromocytoma resection requires prompt control to avoid major and potentially lethal cardiac and neurologic complications. This article reports the planned and successful use of clevidipine (Cleviprex) as the "sole agent" for intraoperative blood pressure management in 2 adult patients with a diagnosis of pheochromocytoma undergoing elective open adrenalectomy. Clevidipine effectively and promptly provided predictable blood pressure control in both patients.

Gene expression profiling of calcium-channel antagonists in the heart of hypertensive and normotensive rats reveals class specific effects

Calcium channel blockers (CCB) differ in their effects on the cardiovascular system with diltiazem being less negatively ionotrop as compared to verapamil. Diltiazem is mainly used to treat supraventricular tachycardia, vasospastic angina and the Raynaud's syndrome. Little is known about the molecular effects of benzothiazepins on cardiac gene expression. We therefore investigated the effects of diltiazem on cardiac gene expression in normotensive and hypertensive rats with left ventricular hypertrophy and compared the results with our previous findings on verapamil and nifedipine. Spontaneously hypertensive (SHR) and normotensive Sprague Dawley (SD) rats were treated with 15mg/kg diltiazem b.i.d. for 3days. Total RNA was isolated from surgically removed hearts and the gene expression of ion channels, ion transporters and their associated partners, calcium handling proteins as well as stress and cellular differentiation markers was investigated by RT-PCR. Subsequently, hierarchical gene cluster analysis was performed to decode treatment effects of different classes of CCBs. CCB treatment of normotensive and hypertensive rats revealed class specific effects with diltiazem specifically repressing cardiac genes pertinent for ion homeostasis and excitation-contraction coupling in normotensive but not hypertensive rats. Conversely, verapamil and nifedipine caused predominantly repression of genes to affect ion homeostasis and contractile dysfunction in spontaneously hypertensive rats; nonetheless, genes coding for calcium-handling proteins were up-regulated. Unlike diltiazem treatment of normotensive rats with verapamil and/or nifedipine did not influence cardiac gene expression. The effects of diltiazem on cardiac gene expression provide a molecular rationale for its use in the treatment of vasospastic angina.

Leg edema with (S)-amlodipine vs conventional amlodipine given in triple therapy for hypertension: a randomized double blind controlled clinical trial

BACKGROUND

Leg edema is a common adverse effect of dihydropyridine Calcium Channel Blockers (CCB) that may need dose reduction or drug withdrawal, adversely affecting the antihypertensive efficacy. Leg edema is reported to occur less often with (S)-amlodipine compared to conventional racemic amlodipine. We aimed to find the incidence of leg edema as a primary outcome and antihypertensive efficacy with (S)-amlodipine compared to conventional amlodipine.

METHODS

This prospective, double-blind, controlled clinical trial randomized 172 hypertensive patients, not controlled on beta-blockers (BB) and angiotensin converting enzyme inhibitors/angiotensin receptor blockers (ACEI/ARB), to either conventional amlodipine (5-10 mg; n = 86) or (S)-amlodipine (2.5-5 mg; n = 86), while continuing their previous anti-hypertensive medications. Sample was sufficient to find a difference in edema between the interventions with 80 % power at 5 % significance level. Intension to treat analysis (ITT) for safety data and per protocol analysis for efficacy data was performed. Fischer's exact test was applied to observe difference between responder rates and proportions of subjects having peripheral edema in the two groups. Pitting edema test scores were compared using Mann-Whitney test.

RESULTS

Altogether 146 patients (amlodipine, n = 76 and (S)-amlodipine, n = 70) completed 120 days treatment. Demographic variables and treatment adherence were comparable in the two groups. Incidence of new edema after randomization was 31.40 % in test group and 46.51 % in control group [p = 0.03; absolute risk reduction (ARR) = 15.1 %; Number Needed to Treat (NNT) = 7, ITT analysis]. Pitting edema score and patient rated edema score increased significantly in the control compared to test group (p = 0.038 and 0.036 respectively) after treatment period. Edema scores increased significantly in the control group from baseline (p < 0.0001). Responders in blood pressure were 98.57 % in test and 98.68 % in control group. Most common adverse events (AE) were pitting edema and increased urinary frequency. Incidence of all AEs other than edema was similar in both groups. Two serious AEs occurred unrelated to therapy. Biochemical and ECG parameters in the two groups were comparable.

CONCLUSIONS

In hypertensive patients not controlled on prior BB and ACEI/ARB therapy, addition of (S)-amlodipine besylate at half the dose of conventional amlodipine provides better tolerability with reduced incidence of peripheral edema, and equal antihypertensive efficacy compared to amlodipine given at usual doses.

TRIAL REGISTRATION

Sri Lanka Clinical Trials registry: www.slctr.lk, SLCTR/2013/006.

Pilot Trial of Intravenous Lipid Emulsion Treatment for Severe Nifedipine-Induced Shock

Animal studies and human case reports show promise in using lipid rescue to treat refractory calcium channel antagonist toxicity. However, the majority of research and clinical experience has focused on non-dihydropyridine agents. Thus, we sought to investigate the value of lipid emulsion (ILE) therapy for dihydropyridine-induced shock. This IACUC-approved study utilized seven swine that were sedated with alpha-chloralose, mechanically ventilated, and instrumented for drug delivery and hemodynamic measures. After stabilization and basal measures, nifedipine (0.01875 mg/kg/min) was infused until imminent cardiac arrest (seizure, end tidal CO2 < 10 mmHg, bradydysrhythmia, or pulseless electrical activity). Animals then received a 7 mL/kg bolus of 20% lipid emulsion via central catheter. Lipid circulation was visually confirmed by the presence of fat in peripheral arterial blood. Hemodynamics were continuously monitored until 10 min after lipid bolus. Surviving animals were euthanized. Pre- and post-lipid treatment parameters were analyzed using the Wilxocon signed rank test (p <0.05 significant). Nifedipine toxicity was characterized by vasodilatory hypotension, impaired vascular contractility, and tachycardia with terminal bradycardia. The median time to imminent cardiac arrest from start of nifedipine infusion was 218 min. Lipid treatment did not improve hemodynamics or restore circulation in any animal. There was no benefit from lipid rescue in this model of nifedipine toxicity. Further study of ILE for dihydropyridine toxicity is warranted but initial animal model results are not promising.

Effect of the human therapeutic drug diltiazem on the haematological parameters, histology and selected enzymatic activities of rainbow trout Oncorhynchus mykiss

Diltiazem is a pharmaceutical belonging to a group of calcium channel blockers (CCB) that is widely used in the treatment of angina pectoris and hypertension. The objective of the present study was to assess the effect of diltiazem on rainbow trout (Oncorhynchus mykiss). Juvenile trout were exposed for 21 and 42 days to three nominal concentrations of diltiazem: 0.03 μg L(-1) (environmentally relevant concentration), 3 μg L(-1), and 30 μg L(-1) (sub-lethal concentrations). The number of mature neutrophilic granulocytes was significantly increased by 450 and 400% in fish exposed to 3 μg L(-1) and 30 μg L(-1) diltiazem compared to the control, respectively. Antioxidant enzyme activity was affected in liver and gills of fish exposed to all tested concentrations of diltiazem but the changes were mostly transient and not concentration dependent. Creatine kinase activity was markedly increased (ranging from 520 to 845%) at all tested diltiazem concentrations at the end of the exposure indicating muscle and/or kidney damage. The highest concentration was associated with histological changes in heart, liver, and kidney. These alterations can be attributed to the effects of diltiazem on the cardiovascular system, similar to those observed in the human body, as well as to its metabolism. At the environmentally relevant concentration, diltiazem was found to induce some alterations in the blood, gills, and liver of fish, indicating its potential for adverse effects on non-target organisms in the aquatic environment.

The Need for a Rational Approach to Vasoconstrictive Syndromes: Transcranial Doppler and Calcium Channel Blockade in Reversible Cerebral Vasoconstriction Syndrome

INTRODUCTION

Reversible cerebral vasoconstriction syndrome (RCVS) typically affects young patients and left untreated can result in hemorrhage or ischemic stroke. Though the disorder has been well characterized in the literature, the most appropriate way to diagnose, treat, and evaluate therapeutic response remains unclear. In previous studies, transcranial Doppler ultrasound (TCD) has shown elevated velocities indicative of vasospasm. This imaging modality is noninvasive and inexpensive; an attractive option for diagnosis and therapeutic monitoring if it is sensitive enough to detect changes in the acute setting given that RCVS often affects the distal vessels early in the course of disease. There is also limited data that calcium channel blockade may be effective in treating vasospasm secondary to RCVS, though the agent of choice, formulation, and dose are unclear.

METHODS

We report a small cohort of seven patients presenting with thunderclap headache whose vascular imaging was consistent with RCVS. All were treated with calcium channel blockade and monitored with TCD performed every 1-2 days.

RESULTS

On presentation, TCD correlated with standard neuroimaging findings of vasospasm (on MR, CT, and conventional angiography). TCD was also able to detect improvement in velocities in the acute setting that correlated well with initiation of calcium channel blockade. Long-acting verapamil appeared to have the greatest effect on velocities compared to nimodipine and shorter-acting calcium channel blockers.

CONCLUSION

Though small, our cohort demonstrates potential utility of TCD to monitor RCVS, and relative superiority of extended-release verapamil over other calcium channel blockers, illustrating the need for larger randomized trials.

An evaluation of the effect of an angiotensin-converting enzyme inhibitor on the growth rate of small abdominal aortic aneurysms: a randomized placebo-controlled trial (AARDVARK)

Aims

The AARDVARK (Aortic Aneurysmal Regression of Dilation: Value of ACE-Inhibition on RisK) trial investigated whether ACE-inhibition reduces small abdominal aortic aneurysms (AAA) growth rate, independent of blood pressure (BP) lowering.

Methods and results

A three-arm, multi-centre, single-blind, and randomized controlled trial (ISRCTN51383267) was conducted in 14 hospitals in England. Subjects aged ≥55 years with AAA diameter 3.0–5.4 cm were randomized 1:1:1 to receive perindopril arginine 10 mg, or amlodipine 5 mg, or placebo and followed 3–6 monthly over 2 years. The primary outcome was aneurysm growth rate (based on external antero-posterior ultrasound measurements in the longitudinal plane), determined by multi-level modelling to provide maximum likelihood estimates. Two hundred and twenty-four subjects were randomized (2011–2013) to placebo (n = 79), perindopril (n = 73), or amlodipine (n = 72). Mean (SD) changes in mid-trial systolic BP (12 months) were 0.5 (14.3) mmHg, P = 0.78 compared with baseline, −9.5 (13.1) mmHg (P < 0.001), and −6.7 (12.0) mmHg (P < 0.001), respectively. No significant differences in the modelled annual growth rates were apparent [1.68 mm (SE 0.2), 1.77 mm (0.2), and 1.81 mm (0.2), respectively]. The estimated difference in annual growth between the perindopril and placebo groups was 0.08 mm (CI −0.50, 0.65). Similar numbers of AAAs in each group reached 5.5 cm diameter and/or underwent elective surgery: 11 receiving placebo, 10 perindopril, and 11 amlodipine.

Conclusion

Small AAA growth rates were lower than anticipated, but there was no significant impact of perindopril compared with placebo or placebo and amlodipine, combined despite more effective BP lowering.

Bioconcentration, metabolism and half-life time of the human therapeutic drug diltiazem in rainbow trout Oncorhynchus mykiss

Diltiazem is a human therapeutic drug and a member of the group of calcium channel blockers having widespread use in the treatment of angina pectoris and hypertension. The objective of the present study was to assess the bioconcentration, metabolism, and half-life time of diltiazem in rainbow trout Oncorhynchus mykiss. Juvenile trout were exposed for 21 and 42 days to three nominal concentrations of diltiazem: 0.03 µg L(-1) (environmentally relevant concentration), 3 µg L(-1), and 30 µg L(-1) (sub-lethal concentrations). The bioconcentration factor (BCF) of diltiazem was relatively low (0.5-194) in analysed tissues, following the order kidney > liver > muscle > blood plasma. The half-life of diltiazem in liver, kidney, and muscle was 1.5 h, 6.2 h, and 49 h, respectively. The rate of metabolism for diltiazem in liver, kidney, muscle, and blood plasma was estimated to be 85 ± 9%, 64 ± 14%, 46 ± 6%, and 41 ± 8%, respectively. Eight diltiazem metabolites were detected. The presence of desmethyl diltiazem (M1), desacetyl diltiazem (M2), and desacetyl desmethyl diltiazem (M3) suggests that rainbow trout metabolize diltiazem mainly via desmethylation and desacetylation, similar to mammals. In addition, diltiazem undergoes hydroxylation in fish. At environmentally relevant concentrations, diltiazem and its metabolites were identified in liver and kidney, indicating the potential for uptake and metabolism in non-target organisms in the aquatic environment.

Harnessing the Flow of Excitation: TRP, Voltage-Gated Na(+), and Voltage-Gated Ca(2+) Channels in Contemporary Medicine

Cellular signaling in both excitable and nonexcitable cells involves several classes of ion channels. Some of them are of minor importance, with very specialized roles in physiology, but here we concentrate on three major channel classes: TRP (transient receptor potential channels), voltage-gated sodium channels (Nav), and voltage-gated calcium channels (Cav). Here, we first propose a conceptual framework binding together all three classes of ion channels, a "flow-of-excitation model" that takes into account the inputs mediated by TRP and other similar channels, the outputs invariably provided by Cav channels, and the regenerative transmission of signals in the neural networks, for which Nav channels are responsible. We use this framework to examine the function, structure, and pharmacology of these channel classes both at cellular and also at whole-body physiological level. Building on that basis we go through the pathologies arising from the direct or indirect malfunction of the channels, utilizing ion channel defects, the channelopathies. The pharmacological interventions affecting these channels are numerous. Part of those are well-established treatments, like treatment of hypertension or some forms of epilepsy, but many other are deeply problematic due to poor drug specificity, ion channel diversity, and widespread expression of the channels in tissues other than those actually targeted.

Persistent phenotypic shift in cardiac fibroblasts: impact of transient renin angiotensin system inhibition

Fibrotic cardiac remodeling ultimately leads to heart failure - a debilitating and costly condition. Select antihypertensive agents have been effective in reducing or slowing the development of cardiac fibrosis. Moreover, some experimental studies have shown that the reduction in fibrosis induced by these agents persists long after stopping treatment. What has not been as well investigated is whether this transient treatment results in a protection against future fibrotic cardiac remodeling. In the present review, previously published studies are re-examined to assess whether the relative percent increase in collagen deposition over an off-treatment period is attenuated, relative to control, following transient antihypertensive treatment in young or adult rats. Present findings suggest that transient inhibition of the renin angiotensin system (RAS) not only produces a sustained reduction in cardiac fibrosis, but also results in a degree of protection against future collagen deposition. In addition, prior transient RAS inhibition appears to alter the cardiac fibroblast phenotype such that these cells show a muted response to myocardial injury - namely reduced proliferation, chemokine release, and collagen deposition. This review puts forth several potential mechanisms underlying this long-term cardiac protection that is afforded by transient RAS inhibition. Specifically, fibroblast phenotypic change, cardiac fibroblast apoptosis, sustained suppression of the RAS, persistent reduction in left ventricular hypertrophy, and persistent reduction in arterial pressure are each discussed. Identifying the mechanisms ultimately responsible for this change in cardiac fibroblast response to injury, hypertension, and aging may reveal novel targets for therapy.

Impact of use of angiotensin II receptor blocker on all-cause mortality in hemodialysis patients: prospective cohort study using a propensity-score analysis

BACKGROUND

It is controversial whether treatment with an angiotensin II receptor blocker (ARB) or a calcium channel blocker (CCB) improves prognosis of hemodialysis (HD) patients.

METHODS

This study was designed as a multicenter prospective cohort study. HD patients (n = 1071) were enrolled from 22 institutes in January 2009 and followed up for 3 years. Patients with missing data, kidney transplantation or retraction of consent during the follow-up period (n = 204) were excluded, and 867 patients contributed to analysis of mortality. Propensity score (PS) for use of ARB and that for CCB was calculated using a multiple logistic regression model.

RESULTS

ARB and CCB were prescribed in 45.6 and 54.7 % of patients at enrollment. During the 3-year follow-up period, all-cause mortality and cardiovascular mortality rates were 18.8 and 5.1 %, respectively. Kaplan-Meier curves showed that all-cause and cardiovascular mortality rates were lower in the ARB group than in the non-ARB group, though the mortality rates were similar in the CCB group and non-CCB group. In PS-stratified Cox regression analysis, ARB treatment was associated with 34 and 45 % reduction of all-cause death and cardiovascular death, respectively. In PS matching analysis, ARB treatment was associated with a significant reduction (46 % reduction) in the risk of all-cause death. A significant impact of CCB treatment on all-cause or cardiovascular mortality was not detected in PS analysis.

CONCLUSIONS

The use of an ARB, but not a CCB, is associated with reduced all-cause and cardiovascular mortalities in patients on HD.

Inhibition of Peripheral Nerve Scarring by Calcium Antagonists, Also Known as Calcium Channel Blockers

The aim of this research was to investigate the impact of calcium channel blockers (verapamil) on the formation of scars in the sciatic nerve anastomosis after peripheral nerve injury. One hundred twenty healthy, male Sprague-Dawley rats were selected and prepared with right sciatic nerve injury for this study. Samples were selected at the fourth and 12th weeks, respectively, after treatment and observations were made on the nerve anastomosis healing and diameter. Image analysis and statistical processing were carried out relating to the results of the study. The diameter of the anastomosis of the treatment group at weeks 4 and 12 was noticeably smaller than the control group (P < 0.05). In the treatment group at week 4, there were many vesicles observed in the fibroblasts' cytosol and in the control group, the fibroblasts exhibited high number of rough endoplasmic reticulum. The collagen content of the nerve scarring at week 12 in the treatment group was apparently less than the control group (P < 0.01). The calcium channel blocker (verapamil) reduced the axon resistance through the anastomosis during nerve regeneration. It can effectively inhibit the formation of scarring from nerve injury. It also provided an excellent microenvironment for the regeneration of nerve fibers.

Missing diagnosis: gingival hypertrophy due to amlodipine

Gingival hypertrophy (GH) is a well-known physical manifestation due to inflammatory conditions, pregnancy, vitamin C deficiency, systemic diseases like leukemia, Wegners granulomatosis, and various drugs like anticonvulsants, immunosuppresant, and calcium channel blockers (CCBs).We present here a case of a 45-year-old woman, who has been taking Amlodipine 10mg once a day together with Atenelol 50mg per day for one and half years, and has subsequently developed gum hypertrophy. This manifestation was reversed after stopping of Amlodipine. Though this case presentation is described in literature, we hereby present it in a pictorial form, to sensitize the treating physician toward it.

A multifaceted approach to calcium channel blocker overdose: a case report and literature review

Calcium channel blocker toxicity can be devastating. Initial therapy with fluid, calcium, and adrenoreceptor agonists should be prompt and novel therapies can be added if no response. Determining cardiogenic shock versus vasoplegia with echocardiogram or other hemodynamic monitoring may guide treatment options.

Randomized placebo-controlled clinical trial of a chewable formulation of amlodipine for the treatment of hypertension in client-owned cats

Background

There is an unmet clinical need for a cat‐specific formulation of amlodipine to treat hypertensive cats.

Objectives

To assess the efficacy of chewable amlodipine tablets in reducing systolic blood pressure (SBP) in cats diagnosed with systemic arterial hypertension.

Animals

Seventy‐seven client‐owned cats with systemic hypertension were included (median age 14 years).

Methods

The study was randomized, double‐blinded, and placebo‐controlled. Forty‐two cats received 0.125–0.50 mg/kg amlodipine once daily for 28 days; 35 cats received placebo. After 28 days all cats continued with amlodipine for 2–3 months in an open‐label phase. Blood pressure was measured using high definition oscillometry. A responder was defined as a cat showing a decrease of SBP to <150 mmHg at 28 days or a decrease from baseline ≥15%.

Results

Sixty‐one cats completed the study. The responder rate was 63% in amlodipine group and 18% in placebo group. Cats receiving amlodipine were 7.9 (95% CI 2.6–24.1) times more likely to be classified as responders when compared to those receiving placebo (P < .001). From a mean (±SD) baseline value of 181 (±12) mmHg, SBP decreased to 154 (±17) mmHg with amlodipine and to 170 (±21) mmHg with placebo (P < .001). The voluntary acceptance rate of amlodipine formulation was 73%.

Conclusions and Clinical Importance

The chewable amlodipine tablet effectively reduced SBP compared with placebo in hypertensive cats, and was well‐tolerated. It can be used concomitantly with angiotensin‐converting enzyme inhibitors and in cats with chronic kidney disease.

A novel tacrine-dihydropyridine hybrid (-)SCR1693 induces tau dephosphorylation and inhibits Aβ generation in cells

AChE inhibitors are the first choice for the treatment of Alzheimer׳s disease (AD), but they could only delay the progression of cognitive and behavioral dysfunction, and fail to reverse neuronal damage. Calcium channel blockers have been identified to have protective effect on neurons. Thus, therapy targeting both AChE and calcium channels is supposed to be more effective in AD treatment. In the present study, we explored the effect of a synthesized juxtaposition of an AChE inhibitor and a Calcium channel blocker (named (-)SCR1693) on tau phosphophorylation and Aβ generation. The results showed that: (1) Compared with higher concentrations, (-)SCR1693 incubation in low concentrations such as 0.4, 2, 4μM for 24h did not affect the cell viability of HEK293/tau (HEK293 cells stably transfected with human tau40) and N2a/APP (N2a cells stably transfected with human APP) cells; (2) long-term treatment of cells with (-)SCR1693 (0.4, 2, 5μM) (24h) induced tau dephosphorylation and reduced the total tau level in HEK293/tau cells. Short-term treatment (6h) also resulted in tau dephosphorylation, but did not reduce the total tau level; and (3) (-)SCR1693 (0.4, 2, 4μM) incubation inhibited Aβ generation and release dramatically in N2a/APP cells. We conclude that the novel tacrine-dihydropyridine hybrid (-)SCR1693 in low concentrations could reduce total and phosphorylated tau levels, inhibit the generation and release of Aβ in cells. Thus, (-)SCR1693 may be a potential candidate for effectively treating AD.

Low dose amlodipine-induced gingival enlargement: A clinical case series

Gingival enlargement sometimes has an adverse effect of certain systemic drugs such as the use of anticonvulsants, phenytoin, antihypertensive, calcium channel blockers and immunosuppressant, cyclosporine. Amlodipine, a relatively newer calcium channel blocker drugs, exhibit adverse effect of gingival enlargement in middle to older aged adults. There are very few reports of amlodipine-induced gingival enlargement at a lower dose (5 mg). In this article, three cases of amlodipine-induced gingival enlargement in the age range of 50-65 years old hypertensive patient with a lower dose of amlodipine (5 mg).

Prospective randomized study of the tolerability and efficacy of combination therapy for hypertensive chronic kidney disease: results of the PROTECT-CKD study

BACKGROUND

We conducted a randomized, open-label trial to determine which of the antihypertensive drugs was most beneficial for CKD patients with hypertension in spite of treatment with an angiotensin receptor blocker (ARB).

METHODS

Patients 20-75 years of age who had CKD according to the definition in the K/DOQI Guidelines and hypertension (systolic blood pressure ≥130 mmHg and/or diastolic blood pressure ≥80 mmHg) with the usual dose of an ARB were randomly assigned to receive losartan 50 mg plus 5 mg of the calcium channel blocker amlodipine (CCB group, n = 37), 5 mg of the angiotensin-converting enzyme inhibitor enalapril (ACEI group, n = 36), or 12.5 mg of the thiazide diuretic hydrochlorothiazide (HCTZ group, n = 36). The primary endpoints were changes in blood pressure (BP), ratio of urinary excretion of protein to creatinine (UPCR), tolerability, and eGFR during the 12-month treatment period compared with control period.

RESULTS

There were no significant differences in BP and tolerability between the three groups. The percentage changes in UPCR at 12 months after start of the combination therapy were significantly different in the HCTZ group (-26.3 ± 11.1 %, mean ± SE) and CCB group (+46.7 ± 33.6 %, p < 0.05), while eGFR was significantly lower in the HCTZ group than in the ACEI group or CCB group at 4 months but not at 12 months.

CONCLUSION

Addition of diuretics, CCB, or ACEI to ARB was equally effective for the control of hypertension in CKD, while, in terms of urinary excretion of protein, diuretics may be better than CCB.

Relation between stent thrombosis and calcium channel blocker after drug-eluting stent implantation: Kumamoto Intervention Conference Study (KICS) registry

BACKGROUND

Stent thrombosis (ST) has emerged as a severe complication of percutaneous coronary intervention (PCI). Since the occurrence of ST is lower in Japan than Western countries, there are few data to predict ST after drug-eluting stent (DES) implantation in Japan. We examined the independent predictors of ST incidence after DES implantation in Japanese patients, including the use of calcium channel blockers (CCBs).

METHODS AND RESULTS

We used data from the Kumamoto Intervention Conference Study registry. There were 6286 consecutive patients enrolled from June 2008 to March 2011. Among them, we analyzed 3493 patients who underwent DES implantation. The incidence of definite/probable ST throughout a median follow-up period of 364 days was 0.57% (20 patients). There were 8 patients with early ST (within 30 days), 8 patients with late ST (between 31 and 365 days), and 4 patients with very late ST (after 1 year). The frequency of CCB use was significantly lower in ST than non-ST patients (25.0% versus 51.4%, respectively, p=0.016). Multiple regression analysis showed that longer stent length (p=0.034), acute coronary syndrome (p=0.039), and the absence of CCB use (p=0.046) were significant and independent predictors of ST within 1 year.

CONCLUSIONS

These results suggest that CCB use may be associated with a decreased risk of ST after DES implantation within 1 year in Japanese patients.

Opioid dependence and substitution therapy: thymoquinone as potential novel supplement therapy for better outcome for methadone maintenance therapy substitution therapy

Methadone is widely being used for opioid substitution therapy. However, the administration of methadone to opioid dependent individual is frequently accompanied by withdrawal syndrome and chemical dependency develops. Other than that, it is also difficult to retain patients in the treatment programme making their retention rates are decreasing over time. This article is written to higlights the potential use of prophetic medicines, Nigella sativa, as a supplement for opioid dependent receiving methadone. It focuses on the potential role of N. sativa and its major active compound, Thymoquinone (TQ) as a calcium channel blocking agent to reduce withdrawal syndrome and opioid dependency.

Azelnidipine, Not Amlodipine, Induces Secretion of Vascular Endothelial Growth Factor From Smooth Muscle Cells and Promotes Endothelial Tube Formation

Background

We previously reported that the calcium channel blocker (CCB) nifedipine-induced secretion of vascular endothelial growth factor (VEGF) from human coronary smooth muscle cells (HCSMCs) promoted human coronary endothelial cell (HCEC) tube formation. Therefore, we analyzed whether other CCBs, azelnidipine and amlodipine, also induced the secretion of VEGF and promoted HCEC tube formation, and the underlying molecular mechanisms.

Methods

To evaluate the tube formation, HCECs were grown on Matrigel for 18 hours in the supernatants from HCSMCs that had been treated with different kinds of reagents. Concentrations of VEGF in cultured HCSMCs were determined by specific enzyme immunoassays. Nuclear extracts from HCSMCs were prepared, and nuclear factor-kappa B (NF-κB) activation was measured by EZ-Detect^TM Transcription Factor Kits for NF-κB p50 or p65.

Results

Although azelnidipine dose-dependently stimulated the significant secretion of VEGF from HCSMCs and this stimulation was abolished by a protein kinase C inhibitor, amlodipine-induced secretion of VEGF was significantly lower than that induced by azelnidipine. The medium derived from azelnidipine (at up to 2 μM)-treated HCSMCs led to HCEC tube formation, whereas that obtained with amlodipine did not. Azelnidipine-induced tube formation was blocked by an inhibitor of kinase insert domain-containing receptor/fetal liver kinase-1 tyrosine kinase. Azelnidipine at up to 2 μM induced NF-κB activation.

Conclusions

Azelnidipine, but not amlodipine, stimulated the secretion of VEGF from HCSMCs and induced HCEC tube formation. This secretion is mediated at least in part via the activation of NF-κB. Azelnidipine may have a novel beneficial effect in improving coronary microvascular blood flow in addition to its main effect of lowering blood pressure.

Combined treatment for a combined enlargement

Calcium channel blockers are widely used in medical practice for the management of hypertension and in the prophylaxis of angina. Gingival overgrowth is now a recognized unwanted effect associated with many of calcium channel blockers. This can have a significant effect on the quality of life as well as increasing the oral bacterial load by generating plaque retention sites. Amlodipine, a third generation calcium channel blockers has been shown to promote gingival overgrowth, although reported in very limited cases. The management of gingival overgrowth seems to be directed at controlling gingival inflammation through a good oral hygiene regimen. However, in severe cases, surgical excision is the most preferred method of treatment, followed by rigorous oral hygiene procedures. This case report describes the management of gingival overgrowth in a hypertensive patient taking amlodipine.

Calcium channel blocker attenuated opioid withdrawal syndrome

Case

A 61-year-old woman was diagnosed with deep cervical abscess and enlarged mediastinal abscess. These required a protracted period of mechanical ventilation and neck and thoracic drainage surgery with daily wound lavage, necessitating the administration of large amounts of fentanyl and dexmedetomidine. After extubation, fentanyl was discontinued but dexmedetomidine was continued, and she developed hypertension, tachycardia, tachypnea, and hyperthermia within several hours; therefore, she was diagnosed with opioid withdrawal syndrome. Her symptoms failed to improve with either an increased dexmedetomidine dose or a diltiazem infusion for symptomatic management. Ultimately, 20 mg nifedipine was given through a nasogastric tube, which led to a resolution of withdrawal symptoms.

Outcome

This is the first case of calcium channel blockers attenuating opioid withdrawal syndrome symptoms in a human.

Conclusion

Calcium channel blockers might be alternative therapy to refractory opioid withdrawal syndrome. Case accumulation in the future is expected.

L-type Ca2+ channel blockers inhibit the window contraction of mouse aorta segments with high affinity

L-type calcium channel blockers (LCCBs) reduce blood pressure more effectively in hypertensive than in normotensive subjects and are more effective in vascular smooth muscle (VSM) than in cardiac muscle. This has been explained by the depolarized resting potential of VSM in comparison with heart muscle cells and during hypertension, because both favor the "high affinity" inactivated state of the L-type calcium channel (LCC). Depolarized resting potentials, however, also increase Ca(2+) influx via window, non-inactivating LCC. The present study investigated whether these channels can be effectively blocked by nifedipine, verapamil or diltiazem, as representatives of different LCCB classes. C57Bl6 mouse aortic segments were depolarized by 50mM K(+) to attain similar degree of inactivation. The depolarization evoked biphasic contractions with the slow force component displaying higher sensitivity to LCCBs than the fast component. Removal of the fast force component increased, whereas stimulation of Ca(2+) influx with the dihydropyridine BAY K8644, a structural analog of nifedipine, decreased the efficacy of the LCCBs. Addition of LCCBs during the contraction caused concentration-dependent relaxation, which was independent of the presence of a fast force component, but still showed lower sensitivity in the presence of BAY K8644. Our data suggest that steady-state contractions by depolarization with 50mM K(+) are completely due to window Ca(2+) influx, which is preferentially inhibited by LCCBs. Furthermore, results point to interactions between the LCCB receptors and Ca(2+) ions or BAY K8644. The high affinity for open, non-inactivating LCC may play a dominant role in the anti-hypertensive effects of LCCBs.

Comparison of effects of azelnidipine and trichlormethiazide in combination with olmesartan on blood pressure and metabolic parameters in hypertensive type 2 diabetic patients

Aims/Introduction:  Angiotensin II type 1 receptor blockers (ARB) are regarded as first-line treatment for type 2 diabetes with hypertension. However, lowering blood pressure to the target level often requires more than one antihypertensive agent as recommended by the guideline. In this open-label, prospective, crossover clinical trial, we compared the effects of combination treatment of ARB with a calcium channel blocker (CCB) or with a low-dose thiazide diuretic on blood pressure (BP) and various metabolic parameters in hypertensive patients with type 2 diabetes.

MATERIALS AND METHODS

  A total of 39 Japanese type 2 diabetics with hypertension treated with olmesartan (20 mg/day) for at least 8 weeks were recruited to this study. At study entry, treatment was switched to either olmesartan (20 mg/day)/azelnidipine (16 mg/day) or olmesartan (20 mg/day)/trichlormethiazide (1 mg/day) and continued for 12 weeks. Then, the drugs were switched and treatment was continued for another 12 weeks. We measured clinical blood pressure and various metabolic parameters before and at the end of each study arm.

RESULTS

  Compared with the olmesartan/trichlormethiazide treatment, treatment with olmesartan/azelnidipine achieved superior clinical blood pressure and pulse rate control. In contrast, the treatment with olmesartan/trichlormethiazide resulted in increased HbA1c, serum uric acid and worsening of estimated glomerular filtration rate, though there were no differences in other metabolic parameters including urine 8-hydroxy-2'-deoxyguanosine, C-reactive protein and adiponectin between the two treatments.

CONCLUSIONS

  Our results show that the combination of ARB with azelnidipine is more beneficial with regard to blood pressure control and metabolic outcome than the combination of olmesartan with low dose trichlormethiazide. This trial was registered with UMIN clinical trial registry (no. UMIN000005064). (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00135.x, 2011).

The effects of calcium channel blockade on proliferation and differentiation of cardiac progenitor cells

Cardiogenesis depends on a tightly regulated balance between proliferation and differentiation of cardiac progenitor cells (CPCs) and their cardiomyocyte descendants. While exposure of early mouse embryos to Ca(2+) channel antagonists has been associated with abnormal cardiac morphogenesis, less is known about the consequences of Ca(2+) channel blockade on proliferation and differentiation of CPCs at the cellular level. Here we showed that at embryonic day (E) 11.5, the murine ventricles express several L-type and T-type Ca(2+) channel isoforms, and that the dihydropyridine Ca(2+) channel antagonist, nifedipine, blunts isoproterenol induced increases in intracellular Ca(2+). Nifedipine mediated Ca(2+) channel blockade was associated with a reduction in cell cycle activity of E11.5 CPCs and impaired assembly of the cardiomyocyte contractile apparatus. Furthermore, in cell transplantation experiments, systemic administration of nifedipine to adult mice receiving transplanted E11.5 ventricular cells (containing CPCs and cardiomyocytes) was associated with smaller graft sizes compared to vehicle treated control animals. These data suggest that intracellular Ca(2+) is a critical regulator of the balance between CPC proliferation and differentiation and demonstrate that interactions between pharmacological drugs and transplanted cells could have a significant impact on the effectiveness of cell based therapies for myocardial repair.

Action of Phα1β, a peptide from the venom of the spider Phoneutria nigriventer, on the analgesic and adverse effects caused by morphine in mice

Opioids are standard therapy for the treatment of pain; however, adverse effects limit their use. Voltage-gated calcium channel blockers may be used to increase opioid analgesia, but their effect on opioid-induced side effects is little known. Thus, the goal of this study was to evaluate the action of the peptide Phα1β, a voltage-gated calcium channel blocker, on the antinociceptive and adverse effects produced by morphine in mice. A single administration of morphine (3-10 mg/kg) was able to reduce heat nociception as well as decrease gastrointestinal transit. The antinociception caused by a single injection of morphine was slightly increased by an intrathecal injection of Phα1β (30 pmol/site). Repeated treatment with morphine caused tolerance, hyperalgesia, withdrawal syndrome, and constipation, and the Phα1β (.1-30 pmol/site, intrathecal) was able to reverse these effects. Finally, the effects produced by the native form of Phα1β were fully mimicked by a recombinant version of this peptide. Taken together, these data show that Phα1β was effective in potentiating the analgesia caused by a single dose of morphine as well as in reducing tolerance and the adverse effects induced by repeated administration of morphine, indicating its potential use as an adjuvant drug in combination with opioids.

PERSPECTIVE

This article presents preclinical evidence for a useful adjuvant drug in opioid treatment. Phα1β, a peptide calcium channel blocker, could be used not only to potentiate morphine analgesia but also to reduce the adverse effects caused by repeated administration of morphine.

Effect of verapamil, a calcium channel blocker, on the odontogenic activity of human dental pulp cells cultured with silicate-based materials

INTRODUCTION

This study examines how calcium silicate cement extracts influence the behavior of human dental pulp cells (hDPCs) through calcium channels and active mitogen-activated protein kinase pathways, in particular extracellular signal-related kinase (ERK).

METHODS

HDPCs are treated with various silicon concentrations both with and without verapamil, after which the cells' viability and odontogenic differentiation markers are determined by using PrestoBlue assay and Western blot, respectively.

RESULTS

The silicon promoted cell proliferation and inhibited calcium channel blockers. It was also found that silicon increased ERK and p38 activity in a dose-dependent manner. Furthermore, it raised the expression and secretion of alkaline phosphatase, osteocalcin, dentin sialophosphoprotein, and dentin matrix protein-1. In addition, statistically significant differences (P < .05) have been found in the secretion of osteocalcin in ERK inhibitor + verapamil between the silicon concentrations; these varations are dose-dependent and indicate that ERK signaling is involved in the silicon-induced odontogenic differentiation of hDPCs.

CONCLUSIONS

The current study shows that silicon ions released from calcium silicate substrates play a key role in odontoblastic differentiation of hDPCs through calcium channels and modulate ERK activation.

Calcium channels and their blockers in intraocular pressure and glaucoma

Several factors besides high intraocular pressure assumed to be associated with the development and progression of glaucoma, and calcium channel blockers (CCBs) have been an anticipated option for glaucoma treatment by improving ocular perfusion and/or exerting neuroprotective effects on retinal ganglion cells with safety established in wide and long-term usage. Decrease in IOP has been reported after topical application of CCBs, however, the effect is much smaller and almost negligible after systemic application. Various CCBs have been reported to increase posterior ocular blood flow in vivo and to exert direct neuroprotection in neurons in vitro. Distribution of the drug at a pharmacologically active concentration in the posterior ocular tissues across the blood-brain barrier or blood-retina barrier, especially in the optic nerve head and retina where the ganglion cells mainly suffer from glaucomatous damage, is essential for clinical treatment of glaucoma. Improved visual functions such as sensitivity in the visual field test have been reported after administration of CCBs, but evidences from the randomized studies have been limited and effects of CCBs on blood flow and direct neuroprotection are hardly distinguished from each other.

Calcium influx through L-type channels attenuates skeletal muscle contraction via inhibition of adenylyl cyclases

Skeletal muscle contraction is triggered by acetylcholine induced release of Ca(2+) from sarcoplasmic reticulum. Although this signaling pathway is independent of extracellular Ca(2+), L-type voltage-gated calcium channel (Cav) blockers have inotropic effects on frog skeletal muscles which occur by an unknown mechanism. Taking into account that skeletal muscle fiber expresses Ca(+2)-sensitive adenylyl cyclase (AC) isoforms and that cAMP is able to increase skeletal muscle contraction force, we investigated the role of Ca(2+) influx on mouse skeletal muscle contraction and the putative crosstalk between extracellular Ca(2+) and intracellular cAMP signaling pathways. The effects of Cav blockers (verapamil and nifedipine) and extracellular Ca(2+) chelator EGTA were evaluated on isometric contractility of mouse diaphragm muscle under direct electrical stimulus (supramaximal voltage, 2 ms, 0.1 Hz). Production of cAMP was evaluated by radiometric assay while Ca(2+) transients were assessed by confocal microscopy using L6 cells loaded with fluo-4/AM. Ca(2+) channel blockers verapamil and nifedipine had positive inotropic effect, which was mimicked by removal of extracellular Ca(+2) with EGTA or Ca(2+)-free Tyrode. While phosphodiesterase inhibitor IBMX potentiates verapamil positive inotropic effect, it was abolished by AC inhibitors SQ22536 and NYK80. Finally, the inotropic effect of verapamil was associated with increased intracellular cAMP content and mobilization of intracellular Ca(2+), indicating that positive inotropic effects of Ca(2+) blockers depend on cAMP formation. Together, our results show that extracellular Ca(2+) modulates skeletal muscle contraction, through inhibition of Ca(2+)-sensitive AC. The cross-talk between extracellular calcium and cAMP-dependent signaling pathways appears to regulate the extent of skeletal muscle contraction responses.

The effect of carvedilol on blood glucose levels in normal albino rats

BACKGROUND

Carvedilol is a commonly used drug in hypertension, congestive heart failure in diabetics. It has moderate calcium channel blocking property in addition to α1 and non selective β antagonistic activity. Though some studies bring forth the beneficial effects of Carvedilol in cardiovascular comorbidities in diabetes, there is no consensus on its effects on glycaemic levels.

AIMS

To evaluate the effect of oral Carvedilol administration for 5 days on blood glucose levels in normal albino rats through Oral Glucose Tolerance Test.

MATERIAL AND METHODS

Twelve adult albino rats of either sex weighing between 150 - 200 g were selected from central animal facility and randomly divided into 2 groups - Control [Distilled water (1ml/rat orally)] and Test (0.8mg/kg body weight orally) and the respective drugs were administered over 5 days. Following overnight fasting, on the fifth day 1 hour after the last dose of the respective drug, OGTT was performed. The CBG (Capillary Blood Glucose) levels were measured at 0 min, glucose (2g/kg body weight) dissolved in water was administered to all the rats orally. The blood sample from tail vein (obtained by tail snipping) at 60 and 150 minutes were analysed for CBG levels using a standardized glucometer.

STATISTICAL ANALYSIS

Data was presented as Mean ± SEM. One way ANOVA, independent samples t-test, non-parametric tests, percentages and cross tabs were used in the analysis of data within the same group and between different groups when required.

RESULTS

Carvedilol group showed higher CBG levels at all time intervals of OGTT as compared to the Control group i.e., 0, 60 and 150 minutes, the highest being (103.8±5.029 )mg/dl at 60 minutes and was statistically significant. Carvedilol group however showed lesser inter-interval variation compared to the Control group at the same time intervals respectively but was statistically insignificant.

CONCLUSIONS

Carvedilol has hyperglycaemic potential when given orally for 5 days in normal albino rats. Though it may be beneficial in diabetics for various comorbid conditions, the glycaemic control may worsen during its use in subjects with prediabetes, diabetes, high risk diabetes.

Pharmacotherapy During Saphenous Vein Graft Intervention

Coronary revascularization using saphenous vein grafts is an important treatment modality for patients with severe coronary artery disease. Percutaneous intervention of these grafts is often the best option for patients who develop severe stenosis of the vein grafts. Use of adjunctive glycoprotein IIb/IIIa inhibitors does not confer added benefit with ischemic endpoints as compared with heparin alone, but it increases the risk of bleeding. Bivalirudin used as the primary anticoagulant lowers the risk of bleeding. No-reflow frequently complicates vein graft interventions but can be treated with vasoactive agents such as calcium channel blockers, adenosine, and nitroprusside.

Effects of prototypic calcium channel blockers in methadone-maintained humans responding under a naloxone discrimination procedure

Accumulating evidence suggests that L-type calcium channel blockers (CCBs) attenuate the expression of opioid withdrawal and the dihydropyridine L-type CCB isradipine has been shown to block the behavioral effects of naloxone in opioid-maintained humans. This study determined whether two prototypic L-type CCBs with differing chemical structures, the benzothiazepine diltiazem and the phenylalkamine verapamil, attenuate the behavioral effects of naloxone in methadone-maintained humans trained to distinguish between low-dose naloxone (0.15 mg/70 kg, i.m.) and placebo under an instructed novel-response drug discrimination procedure. Once discrimination was acquired, diltiazem (0, 30, 60, 120 mg) and verapamil (0, 30, 60, 120 mg), alone and combined with the training dose of naloxone, were tested. Diltiazem alone produced 33-50% naloxone- and novel-appropriate responding at 30 and 60 mg and essentially placebo-appropriate responding at 120 mg. Verapamil alone produced 20-40% naloxone- and 0% novel-appropriate responding. Diltiazem at 60 mg decreased several ratings associated with positive mood and increased VAS ratings of "Bad Drug Effects" relative to placebo, whereas verapamil increased ratings associated with euphoria. When administered with naloxone, diltiazem produced 94-100% naloxone-appropriate-responding with 6% novel-appropriate responding at 60 mg (n=3). When administered with naloxone, verapamil produced 60-80% naloxone- and 0% novel-appropriate responding (n=5). Diltiazem decreased diastolic blood pressure and heart rate whereas verapamil decreased ratings of arousal relative to placebo. These results suggest that CCBs with different chemical structures can be differentiated behaviorally, and that diltiazem and verapamil do not attenuate the discriminative stimulus effects of naloxone in humans at the doses tested.

Comparison of effects of cilnidipine and azelnidipine on blood pressure, heart rate and albuminuria in type 2 diabetics with hypertension: A pilot study

Previous studies reported that both cilnidipine and azelnidipine have a renoprotective effect compared with amlodipine. The aim of this study was to compare the effects of cilnidipine and azelnidipine on blood pressure, heart rate and albuminuria. An open-label prospective crossover trial was carried out. We recruited 19 type 2 diabetics treated with amlodipine (5 mg/day) at least for 12 weeks. At study entry, amlodipine was changed to cilnidipine (10 mg/day) or azelnidipine (16 mg/day) and each administered for 16 weeks. Then, the drugs were switched and the treatment was continued for another 16 weeks. Despite no differences in 24-h blood pressure and heart rate between cilnidipine and azelnidipine, treatment with cilnidipine resulted in a greater reduction in urinary albumin:creatinine ratio than azelnidipine. Our results suggested that cilnidipine is more efficient in reducing albuminuria than azelnidipine independent of its blood pressure lowering effect in type 2 diabetic patients with hypertension. This trial was registered with UMIN (no. 000007201).

Excellent tolerance to cilnidipine in hypertensives with amlodipine - induced edema

Background:

Ankle edema is a common adverse effect of amlodipine, an L-type calcium channel blocker (CCB). Cilnidipine is a newer L/N-type CCB, approved for treatment of essential hypertension.

Aim:

This study was designed to determine whether cilnidipine can produce resolution of amlodipine-induced edema while maintaining adequate control of hypertension.

Materials and Methods:

A prospective study was performed on 27 patients with essential hypertension with amlodipine-induced edema. Concomitant nephropathy, cardiac failure, hepatic cirrhosis, or other causes of edema, and secondary hypertension were excluded by appropriate tests. Amlodipine therapy was substituted in all the cases with an efficacy-equivalent dose of cilnidipine. Clinical assessment of ankle edema and measurement of bilateral ankle circumference, body weight, blood pressure, and pulse rate were performed at onset of the study and after 4 weeks of cilnidipine therapy.

Results:

At completion of the study, edema had resolved in all the patients. There was a significant decrease in bilateral ankle circumference and body weight (P < 0.001). There was no significant change in mean arterial blood pressure and pulse rate.

Conclusions:

Therapy with cilnidipine resulted in complete resolution of amlodipine-induced edema in all the cases without significant worsening of hypertension or tachycardia. Cilnidipine is an acceptable alternative antihypertensive for patients with amlodipine-induced edema.

Amlodipine has a preventive effect on temporal left ventricular hypokinesia after emotional stress compared with an angiotensin II receptor blocker

PURPOSE

We previously reported that α- and β-blockers protected against emotional stress-induced cardiac dysfunction, but the protective effects of other antihypertensive drugs is unknown. The purpose of this study is to evaluate the ability of a calcium channel blocker, amlodipine, to prevent temporal left ventricular hypokinesia after emotional stress compared with an angiotensin II receptor blocker, olmesartan medoxomil.

METHODS

Rats premedicated with amlodipine (0.2 mg/kg), olmesartan (0.8 mg/kg), or vehicle were restrained for 30 min (immobilization stress: IMO) to reproduce emotional stress and then anesthetized to release stress. We measured the fractional area change (FAC) using echocardiography (SONOS5500) with a s12 probe (frequency 5-12 MHz, frame rate 120 Hz) and blood pressure and heart rate at the end of IMO and every 10 for 60 min after IMO.

RESULTS

During IMO, FAC in the amlodipine or the olmesartan group was as high as that in the vehicle group. At 20 min after IMO, FAC in the amlodipine group was significantly higher than in the other two groups (84 ± 8 vs. 60 ± 7 or 68 ± 15 %, p < 0.05). During IMO, blood pressure in the amlodipine or the olmesartan group was significantly lower than with vehicle (119 ± 6 and 110 ± 7 vs. 124 ± 5 mmHg, p < 0.05). After IMO, blood pressure in the olmesartan group was significantly lower than in the other two groups.

CONCLUSION

Acute administration of amlodipine could prevent a sudden drop in cardiac function after acute stress like IMO, but olmesartan did not. Amlodipine might have a protective effect on temporal left ventricular hypokinesia after emotional stress, which might not be related to decreased blood pressure.

Serum calcium level in hypertension

Background:

The alterations in extracellular calcium level may influence intracellular calcium level and possibly play a role in the pathogenesis of essential hypertension.

Aim:

The purpose was to find out the association between serum calcium levels and hypertension; and to compare the serum calcium levels between normotensive controls, hypertensive subjects on calcium channel blockers, and hypertensive subjects on antihypertensive medication other than calcium channel blockers.

Materials and Methods:

Thirty one individuals including normotensives (n = 12) and hypertensives (n = 19) were enrolled for the study and their blood pressure recorded. Hypertensive group was sub divided into two: hypertensives on calcium channel blockers and hypertensives on antihypertensive medication other than calcium channel blockers. Serum calcium levels were measured by Accucare Calcium Arsenazo III kit. Differences between the groups were analyzed using ANOVA.

Results:

No significant difference in serum calcium level was found between normotensive and hypertensive groups; and no correlation was found between calcium levels and the blood pressure. Also the difference in serum calcium levels in hypertensive group on calcium channel blockers and those on antihypertensive other than calcium channel blockers was insignificant.

Conclusions:

Serum calcium levels are tightly regulated. Subtle changes in serum levels do not affect blood pressure.

Prevalence of gingival enlargement secondary to calcium channel blockers in patients with cardiovascular diseases

AIM

The purpose of the present study was to determine the prevalence and extent of gingival overgrowth in patients treated with calcium channel blockers for cardiovascular diseases.

BACKGROUND

Calcium channel blockers are widely used in the treatment of hypertension, vasoplastic angina, and cardiacarrythmias. Gingival overgrowth resulting from the use of calcium channel blockers is of primary concern to dentists. The purpose of the present study is to determine the prevalence and extent of gingival overgrowth in patients treated with calcium channel blockers for various cardiovascular diseases, to assess their periodontal status and to correlate the factors like age, sex, duration, dosage, type of drugs that result in gingival overgrowth.

MATERIALS AND METHODS

A cross-sectional study was done in cardiac patients treated with calcium channel blockers, visiting The Railway hospital, Perumbur, Chennai. Information regarding medical history, type, duration, dosage of medication were recorded and analyzed. The periodontal condition of the patients was assessed using the plaque index, gingival index, calculus index, papillary bleeding index, and extent of gingival overgrowth using appropriate indices. The data was later subjected to statistical analysis.

RESULTS

In this study, a total of 213 cardiac patients (145 males and 68 females) who met the inclusion and exclusion criteria were screened. The patients were between 19 and 69 years.

CONCLUSIONS

From the results of the present study it can be concluded that gingival overgrowth does occur with calcium channel blockers. Elderly males appeared to be more susceptible to the development of drug-induced gingival overgrowth, which was independent of dosage, duration of drug administered but the presence of local factors seemed to aggravate the same.

Photodistributed telangiectasia induced by amlodipine

Calcium channel blockers are widely used antihypertensive drugs, which are uncommonly associated with cutaneous reactions, such as pruritus, urticaria, or alopecia. Photosensitivity presenting with telangiectasia has rarely been described. We present here a case of photodistributed telangiectasia induced clinically by amlodipine and histologically by enlarged capillaries in the upper dermis without signs of vasculitis.

A Stability-indicating HPLC Method for Assay of Lercanidipine Hydrochloride in Tablets and for Determining Content Uniformity

A simple, precise and accurate HPLC method has been developed and validated for assay of lercanidipine hydrochloride in tablets and for determination of content uniformity. An isocratic separation was achieved using a Chromasil YMC Pack C₈, 150 × 4.6 mm i.d., 5µm particle size columns with a flow rate of 1 ml/min and using a UV detector to monitor the elute at 240 nm. The mobile phase consisted of 0.02 M ammonium dihydrogen phosphate buffer:methanol (35:65, v/v) with pH 3.5 adjusted with phosphoric acid. The method was validated for specificity, linearity, pre-cision, accuracy, robustness and solution stability. The specificity of the method was deter-mined by assessing interference from the placebo and by stress testing of the drug (forced degradation). The method was linear over the concentration range of 20-80 µg/ml (r²= 0.9992) with a limit of detection and quantitation of 0.1 and 0.3 µg/ml respectively. Intraday and interday system and method precision were determined and accuracy was between 99.3-101.9 %. The method was found to be robust and suitable for assay of lercanidipine hydrochloride in a tablet formulation and for determination of content uniformity. Degradation products resulting from the stress studies did not interfere with the detection of lercanidipine hydrochloride and the assay is thus stability-indicating.

Management of amlodipine-induced gingival enlargement: Series of three cases

Gingival enlargement is one of the side effects associated with certain drugs. Amlodipine, a calcium channel blocker, used as antihypertensive drug has been found associated with gingival hyperplasia. This case series presents diagnosis and management of amlodipine-induced gingival hyperplasia. Amlodipine-induced gingival enlargement was diagnosed and managed by thorough scaling and root planning. Drug substitution and surgical intervention was performed in first two cases. The pathogenesis of gingival enlargement is uncertain and the treatment is still largely limited to the maintenance of an improved level of oral hygiene and surgical removal of the overgrown tissue. Several factors may influence the relationship between the drugs and gingival tissues as discussed by Seymour et al. Meticulous oral hygiene maintenance, switchover to alternative drug, professional scaling and root planning and surgical excision of enlarged gingival tissue may help overcome the effect of these drugs.

Evaluation of mutagenicity of mebudipine, a new calcium channel blocker

Mebudipine is a new dihydropyridine calcium channel blocker, synthesized in our laboratory, for treatment of hypertension. It has shown a better efficacy than other drugs in this group. For assessing the risks of this drug, certain safety tests in the preclinical stage have been performed. In this study mutagenic effect of mebudipine was evaluated using Ames assay that could assess the mutagenicity of drugs and their metabolites using liver enzymes (S-9 mix). This procedure is approved as a predictive test, with a high predictive value. Salmonella TA102 (Ames assay) was used with and without S-9 in this study. For preparing S-9 mix, rat liver enzymes induced by phenobarbital were separated in KCl 0.154 M (0.154 M), as the solvent. Mebudipine was dissolved in polyethylenglycol 400. Mutagenicity test was performed in 6 doses from 39 μg to 1250 μg per every plate, in the presence and absence of the S-9 mix. The positive control sodium azide was dissolved in a dose of 5 μg/plate dissolved in polyethylenglycol 400 and negative control was polyethylenglycol 400 with no added agent. The colony counts of all doses in plates with S-9 were between 200-400 and in plates without S9 was between100-300. The colony counts in both states (with and without S-9) of all doses were in the range suggested by Ames assay for the safe drugs and were different from the positive control groups and equal to the negative controls. Mebudipine and its metabolites were not found to be mutagen on Salmonella TA102, based on Ames assay.

Risk factors for colonic diverticular bleeding: A Westernized community based hospital study

AIM: To evaluate the risk factors-other than nonsteroidal anti-inflammatory drugs-for colonic diverticular bleeding in a westernized population.

METHODS: One hundred and forty patients, treated for symptomatic diverticular disease in a community based hospital, were included. Thirty (21%) had signs of diverticular bleeding. Age, gender, and the results of colonoscopy were collected and compared to a group of patients with nonbleeding symptomatic diverticulosis. Records were reviewed for comorbidities, such as obesity, alcohol consumption, smoking habits and metabolic diseases. Special emphasis was put on arterial hypertension, cardiovascular events, diabetes mellitus, hyperuricemia and hypercholesterinemia.

RESULTS: There was no difference between patients with diverticular hemorrhage and those with nonbleeding symptomatic diverticulosis regarding gender ratio (male/female 9/21 vs 47/63) and diverticular localisation. Bleeding patients differed in respect to age (73.4 ± 9.9 vs 67. 8 ± 13.0, P < 0.013). Significant differences were found between both groups regarding the presence of hyperuricemia and use of steroids and nonsteroidal anti-inflammatory drugs. Patients with three concomitant metabolic diseases were also identified as being at risk of bleeding. A forward stepwise logistic regression analysis revealed steroids, hyperuricemia and the use of calcium-channel blockers as independent risk factors of bleeding.

CONCLUSION: Beside nonsteroidal anti-inflammatory steroid drug use, antihypertensive medication and concomitant arteriosclerotic diseases are risk factors for colonic diverticular hemorrhage. Our results support the hypothesis of an altered arteriosclerotic vessel as the source of bleeding.

Calcium antagonist prevents calcium flux induced necrosis and apoptosis in ischemic reperfusion of rat liver

Ca(2+) accumulation in mitochondria is responsible for the cell abnormality associated with ischemia and reperfusion injury. The present study was aimed to evaluate the efficacy of Ca(2+) channel blocker- amlodipine on the mitochondrial Ca(2+) accumulation in ischemic and reperfusion (I/R) induced liver injury. Eighteen wistar rats were divided in sham-operated control group-I (n = 6), ischemia and reperfusion group-II (n = 6) and amlodipine treated group-III (1 mg/kg body weight /daily by oral route for 7 days before induced ischemia reperfusion manouver) (n = 6). Rats were subjected to 1h of hepatic ischemia followed by 3 h reperfusion. Mitochondrial Ca(2+) content was measured and damage of mitochondria was confirmed by transmission electron microscopic examination. Bcl-2 gene expression was measured by reverse transcriptase polymerase chain reaction method. Pretreatment with Amlodipine effectively counteracted the alternation in mitochondrial Ca(2+) content. TEM and expression of Bcl-2 protein confirms the restoration of cellular normalcy and accredits the cytoprotective role of Amlodipine against I/R induced hepatic injury. These findings showed that the mechanism of regulation of Bcl-2 gene expression by amlodipine may be the inhibitory action of Ca(2+) entry into mitochondria and prevent apoptosis and necrosis.

Effect of SK&F96365 on store-operated Ca2+ channel currents of Kupffer cells after hepatic ischemia and reperfusion injury in rats

AIM: To investigate the changes of store-operated calcium channel currents (I_SOC) after hepatic ischemia and reperfusion (I/R) injury in isolated Kupffer cells of rats, and the effects of Ca²⁺ channel blockers, SK&F96365, on I_SOC of Kupffer cells.

METHODS: The SD rat model of hepatic I/R injury was established. Liver Kupffer cells were isolated from the rats by in situ perfusion via the portal vein with Ca²⁺/Mg²⁺-free Krebs buffer followed by collagenase digestion. Then Percoll Isopyknic gradient centrifugation was performed. Kupffer cells were purified after selective adhesion. The changes of I_SOC after I/R injury and the effect of SK&F96365 on I_SOC of Kupffer cells were investigated by whole-cell patch-clamp technique.

RESULTS: I_SOC was significantly increased from -78.7 ± 25.2 pA to -159.3 ± 27.3 pA (P < 0.01, n = 15) after I/R injury. SK&F96365 (5, 10, 20, 40, 50 mmol/L) induced a concentration-dependent inhibition of I_SOC with the rate 43.9% ± 18.1%, 59.2% ± 24.0%, 66.3% ± 23.0%, 73.8% ± 17.8%, 80.9% ± 12.6%, respectively, and the IC₅₀ value was 6.53 mmol/L (n = 8).

CONCLUSION: I/R injury can enhance the I_SOC of Kupffer cells, which leads to the activation of the cells, further resulting in the injury of hepatocytes. Calcium channel blocker, SK&F96365, can protect livers from I/R injury by inhibiting the activation of Kupffer cells.