Amlodipine in chronic stable angina: results of a multicenter double-blind crossover trial

Hypertension management in patients with cardiovascular comorbidities

Arterial hypertension is a leading cause of death globally. Due to ageing, the rising incidence of obesity, and socioeconomic and environmental changes, its incidence increases worldwide. Hypertension commonly coexists with Type 2 diabetes, obesity, dyslipidaemia, sedentary lifestyle, and smoking leading to risk amplification. Blood pressure lowering by lifestyle modifications and antihypertensive drugs reduce cardiovascular (CV) morbidity and mortality. Guidelines recommend dual- and triple-combination therapies using renin–angiotensin system blockers, calcium channel blockers, and/or a diuretic. Comorbidities often complicate management. New drugs such as angiotensin receptor-neprilysin inhibitors, sodium–glucose cotransporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, and non-steroidal mineralocorticoid receptor antagonists improve CV and renal outcomes. Catheter-based renal denervation could offer an alternative treatment option in comorbid hypertension associated with increased sympathetic nerve activity. This review summarises the latest clinical evidence for managing hypertension with CV comorbidities.

Rationale and design of the Medical Research Council's Precision Medicine with Zibotentan in Microvascular Angina (PRIZE) trial

Microvascular angina is caused by cardiac small vessel disease, and dysregulation of the endothelin system is implicated. The minor G allele of the non-coding single nucleotide polymorphism (SNP) rs9349379 enhances expression of the endothelin 1 gene in human vascular cells, increasing circulating concentrations of ET-1. The prevalence of this allele is higher in patients with ischemic heart disease. Zibotentan is a potent, selective inhibitor of the ETA receptor. We have identified zibotentan as a potential disease-modifying therapy for patients with microvascular angina. METHODS: We will assess the efficacy and safety of adjunctive treatment with oral zibotentan (10 mg daily) in patients with microvascular angina and assess whether rs9349379 (minor G allele; population prevalence ~36%) acts as a theragnostic biomarker of the response to treatment with zibotentan. The PRIZE trial is a prospective, randomized, double-blind, placebo-controlled, sequential cross-over trial. The study population will be enriched to ensure a G-allele frequency of 50% for the rs9349379 SNP. The participants will receive a single-blind placebo run-in followed by treatment with either 10 mg of zibotentan daily for 12 weeks then placebo for 12 weeks, or vice versa, in random order. The primary outcome is treadmill exercise duration using the Bruce protocol. The primary analysis will assess the within-subject difference in exercise duration following treatment with zibotentan versus placebo. CONCLUSION: PRIZE invokes precision medicine in microvascular angina. Should our hypotheses be confirmed, this developmental trial will inform the rationale and design for undertaking a larger multicenter trial.

Stable Angina Medical Therapy Management Guidelines: A Critical Review of Guidelines from the European Society of Cardiology and National Institute for Health and Care Excellence

Most patients with stable angina can be managed with lifestyle changes, especially smoking cessation and regular exercise, along with taking antianginal drugs. Randomised controlled trials show that antianginal drugs are equally effective and none of them reduced mortality or the risk of MI, yet guidelines prefer the use of beta-blockers and calcium channel blockers as a first-line treatment. The European Society of Cardiology guidelines for the management of stable coronary artery disease provide classes of recommendation with levels of evidence that are well defined. The National Institute for Health and Care Excellence (NICE) guidelines for the management of stable angina provide guidelines based on cost and effectiveness using the terms first-line and second-line therapy. Both guidelines recommend using low-dose aspirin and statins as disease-modifying agents. The aim of this article is to critically appraise the guidelines’ pharmacological recommendations for managing patients with stable angina.

Current Indications for Stenting: Symptoms or Survival CME

The major goals of treating ischemic heart disease are to reduce angina, improve quality of life, and ultimately reduce mortality. While medical therapy can effectively address these aims, there is still much research and debate about the role of percutaneous coronary intervention in the treatment spectrum-specifically, whether or not stenting prolongs life or simply treats symptoms without impacting survival. The data supporting revascularization for survival benefit came from patients who underwent bypass graft surgery prior to the introduction of effective medical management. Although both physicians and patients continue to believe in the life-saving ability of coronary stenting, little data exist to support this belief outside of when used during an acute myocardial infarction. Strategy trials designed to test the benefit of coronary stenting have limitations that have curbed physicians' willingness to accept the results, but they provide the best evidence for how to optimally manage these patients. In this article, we explore the data supporting the use of coronary stenting for various indications and the questions that remain to be answered.

Management of Persistent Angina After Myocardial Infarction Treated With Percutaneous Coronary Intervention: Insights From the TRANSLATE-ACS Study

BACKGROUND

Angina has important implications for patients' quality of life and healthcare utilization. Angina management after acute myocardial infarction (MI) treated with percutaneous coronary intervention (PCI) is unknown.

METHODS AND RESULTS

TRANSLATE-ACS (Treatment With Adenosine Diphosphate Receptor Inhibitors: Longitudinal Assessment of Treatment Patterns and Events After Acute Coronary Syndrome) was a longitudinal study of MI patients treated with percutaneous coronary intervention at 233 US hospitals from 2010 to 2012. Among patients with self-reported angina at 6 weeks post-MI, we described patterns of angina and antianginal medication use through 1 year postdischarge. Of 10 870 percutaneous coronary intervention-treated MI patients, 3190 (29.3%) reported angina symptoms at 6 weeks post-MI; of these, 658 (20.6%) had daily/weekly angina while 2532 (79.4%) had monthly angina. Among patients with 6-week angina, 2936 (92.0%) received β-blockers during the 1 year post-MI, yet only 743 (23.3%) were treated with other antianginal medications. At 1 year, 1056 patients (33.1%) with 6-week angina reported persistent angina symptoms. Of these, only 31.2% had been prescribed non-β-blocker antianginal medications at any time in the past year. Among patients undergoing revascularization during follow-up, only 25.9% were on ≥1 non-β-blocker anti-anginal medication at the time of the procedure.

CONCLUSIONS

Angina is present in one third of percutaneous coronary intervention-treated MI patients as early as 6 weeks after discharge, and many of these patients have persistent angina at 1 year. Non-β-blocker antianginal medications are infrequently used in these patients, even among those with persistent angina and those undergoing revascularization.

Antianginal medications and long-term outcomes after elective catheterization in patients with coronary artery disease

BACKGROUND

Antianginal medications are a class I recommendation by the American College of Cardiology/American Heart Association guidelines for stable ischemic heart disease. We sought to better understand guidance in drug selection and real-life outcomes of antianginal medication use.

HYPOTHESIS

In patients with stable ischemic heart disease, antianginal medications lower mortality.

METHODS

We evaluated 5608 patients with obstructive coronary artery disease (CAD) on elective cardiac catheterization with follow-up through self-administered questionnaires. Patients were classified as being prescribed a particular medication if they received that medication at index catheterization, or within 3 months postcatheterization. The association between antianginal medication use and outcomes was evaluated using Cox proportional hazards models.

RESULTS

Compared with the 11% not prescribed any antianginal medication, patients prescribed antianginal medication were more likely to be older and female; have a history of hypertension, diabetes mellitus, peripheral vascular disease, or 3-vessel CAD; have lower adjusted mortality (hazard ratio [HR]: 0.75, 95% confidence interval [CI]: 0.63-0.89); and experience mortality or myocardial infarction (HR: 0.83, 95% CI: 0.71-0.98). Compared with patients not taking β-blockers (17%), those taking β-blockers had a lower risk of mortality (HR: 0.76, 95% CI: 0.66-0.88). Patients prescribed calcium channel blockers or long-acting nitrates had a higher risk of mortality compared with nonusers (HR: 1.16, 95% CI: 1.04-1.29; HR: 1.20, 95% CI: 1.08-1.34; respectively).

CONCLUSIONS

Antianginal medications are not universally prescribed among obstructive CAD patients; nonuse was associated with higher mortality. For CAD patients with or without prior myocardial infarction, β-blockers were associated with improved long-term survival.

The risk of cardiovascular side effects with anti-anginal drugs

INTRODUCTION

Angina pectoris is a common presenting symptom of underlying coronary artery disease or reduced coronary flow reserve. Patients with angina have impaired quality of life; and need to be treated optimally with antianginal drugs to control symptoms and improve exercise performance. A wide range of antianginal medications are approved for the treatment of angina, and often more than one class of antianginal drugs are used to adequately control the symptoms. This expert opinion highlights the likely cardiac adverse effects of available antianginal drugs, and how to minimize these in individual patients and especially during combination treatment. Areas covered: All approved antianginal drugs, including the older and newly approved medications with different mechanism of action to the older drugs as well as some of the unapproved herbal medications. The safety profiles and potential cardiac side effects of these medications when used as monotherapy or as combination therapy are discussed and highlighted. Expert opinion: Because of the different cardiac safety profiles and possible side effects, we recommend selection of initial drug or adjustment of therapy based on the resting heart rate; blood pressure, hemodynamic status; and resting left ventricular function, concomitant medications and any associated comorbidities.

Pharmacological and emerging therapies in the treatment of chronic angina

Chronic angina is a common manifestation of ischaemic heart disease. Medical treatments are the mainstay approach to reduce the occurrence of angina and improve patients' quality of life. This Series paper focuses on commonly used standard treatments (eg, nitrates, β blockers, and calcium-channel blockers), emerging anti-angina treatments (which are not available in all parts of the world), and experimental treatments. Although many emerging treatments are available, evidence is scarce about their ability to reduce angina and ischaemia.

Evaluating symptoms to improve quality of life in patients with chronic stable angina

Chronic stable angina (CSA) is a significant problem in the United States that can negatively impact patient quality of life (QoL). An accurate assessment of the severity of a patient's angina, the impact on their functional status, and their risk of cardiovascular complications is key to successful treatment of CSA. Active communication between the patient and their healthcare provider is necessary to ensure that patients receive optimal therapy. Healthcare providers should be aware of atypical symptoms of CSA in their patients, as patients may continue to suffer from angina despite the availability of multiple therapies. Patient questionnaires and symptom checklists can help patients communicate proactively with their healthcare providers. This paper discusses the prevalence of CSA, its impact on QoL, and the tools that healthcare providers can use to assess the severity of their patients' angina and the impact on QoL.

Stable angina pectoris: the medical management of symptomatic myocardial ischemia

Coronary artery disease (CAD) remains an important cause of morbidity and mortality and is a serious public health problem. Over the last 4 decades there have been dramatic advances in the both the prevention and treatment of CAD. The management of CAD was revolutionized by the development of effective surgical and percutaneous revascularization techniques. In this review we discuss the importance of the medical management of symptomatic, stable angina. Medical management approaches to both the treatment and prevention of symptomatic myocardial ischemia are summarized. In Canada, organic nitrates, β-adrenergic blocking agents, and calcium channel antagonists have been available for the therapy of angina for more than 25 years. All 3 classes are of proven benefit in the improvement of symptoms and exercise capacity in patients with stable angina. Although there is no clear first choice within these classes of anti-anginal agents, the presence of prior or concurrent conditions (for example, prior myocardial infarction and/or hypertension) plays an important role in the choice of anti-anginal class in individual patients. For some patients, combinations of different anti-anginal agents can be effective; however it is recommended that this approach be individualized. Although not currently available in Canada, other classes of anti-anginal agents have been developed; their mechanism of action and clinical efficacy is discussed. Patients with stable angina have an excellent prognosis. Patients in this category who obtain relief from symptomatic myocardial ischemia may do well without invasive intervention.

Antianginal efficacy and safety of ivabradine compared with amlodipine in patients with stable effort angina pectoris: a 3-month randomised, double-blind, multicentre, noninferiority trial

BACKGROUND AND OBJECTIVE

Current medical therapies for the symptoms of angina pectoris aim to improve oxygen supply and reduce oxygen demand in the myocardium. Not all patients respond to current antianginal monotherapy, or even combination therapy, and a new class of antianginal drug that complements existing therapies would be useful. This study was undertaken to compare the antianginal and anti-ischaemic effects of the novel heart-rate-lowering agent ivabradine and of the calcium channel antagonist amlodipine.

PATIENTS AND METHODS

Patients with a >/=3-month history of chronic, stable effort-induced angina were randomised to receive ivabradine 7.5mg (n = 400) or 10mg (n = 391) twice daily or amlodipine 10mg once daily (n = 404) for a 3-month, double-blind period. Bicycle exercise tolerance tests were performed at baseline and monthly intervals. The primary efficacy criterion was the change from baseline in total exercise duration after 3 months of treatment. Secondary efficacy criteria included changes in time to angina onset and time to 1mm ST-segment depression, rate-pressure product at trough drug activity, as well as short-acting nitrate use and anginal attack frequency (as recorded in patient diaries).

RESULTS

At 3 months, total exercise duration was improved by 27.6 +/- 91.7, 21.7 +/- 94.5 and 31.2 +/- 92.0 seconds with ivabradine 7.5 and 10mg and amlodipine, respectively, both ivabradine groups were comparable to amlodipine (p-value for noninferiority < 0.001). Similar results were observed for time to angina onset and time to 1mm ST-segment depression. Heart rate decreased significantly by 11-13 beats/min at rest and by 12-15 beats/min at peak of exercise with ivabradine but not amlodipine, and rate-pressure product decreased more with ivabradine than amlodipine (p-value vs amlodipine <0.001, at rest and at peak of exercise). Anginal attack frequency and short-acting nitrate use decreased substantially in all treatment groups with no significant difference between treatment groups. The most frequent adverse events were visual symptoms and sinus bradycardia with ivabradine (0.8% and 0.4% withdrawals, respectively) and peripheral oedema with amlodipine (1.5% withdrawals).

CONCLUSIONS

In patients with stable angina, ivabradine has comparable efficacy to amlodipine in improving exercise tolerance, a superior effect on the reduction of rate-pressure product (a surrogate marker of myocardial oxygen consumption) and similar safety.

Antianginal Efficacy and Safety of Ivabradine Compared with Amlodipine in Patients with Stable Effort Angina Pectoris

BACKGROUND AND OBJECTIVE

Current medical therapies for the symptoms of angina pectoris aim to improve oxygen supply and reduce oxygen demand in the myocardium. Not all patients respond to current antianginal monotherapy, or even combination therapy, and a new class of antianginal drug that complements existing therapies would be useful. This study was undertaken to compare the antianginal and anti-ischaemic effects of the novel heart-rate-lowering agent ivabradine and of the calcium channel antagonist amlodipine.

PATIENTS AND METHODS

Patients with a >/=3-month history of chronic, stable effort-induced angina were randomised to receive ivabradine 7.5mg (n = 400) or 10mg (n = 391) twice daily or amlodipine 10mg once daily (n = 404) for a 3-month, double-blind period. Bicycle exercise tolerance tests were performed at baseline and monthly intervals. The primary efficacy criterion was the change from baseline in total exercise duration after 3 months of treatment. Secondary efficacy criteria included changes in time to angina onset and time to 1mm ST-segment depression, rate-pressure product at trough drug activity, as well as short-acting nitrate use and anginal attack frequency (as recorded in patient diaries).

RESULTS

At 3 months, total exercise duration was improved by 27.6 +/- 91.7, 21.7 +/- 94.5 and 31.2 +/- 92.0 seconds with ivabradine 7.5 and 10mg and amlodipine, respectively, both ivabradine groups were comparable to amlodipine (p-value for noninferiority < 0.001). Similar results were observed for time to angina onset and time to 1mm ST-segment depression. Heart rate decreased significantly by 11-13 beats/min at rest and by 12-15 beats/min at peak of exercise with ivabradine but not amlodipine, and rate-pressure product decreased more with ivabradine than amlodipine (p-value vs amlodipine <0.001, at rest and at peak of exercise). Anginal attack frequency and short-acting nitrate use decreased substantially in all treatment groups with no significant difference between treatment groups. The most frequent adverse events were visual symptoms and sinus bradycardia with ivabradine (0.8% and 0.4% withdrawals, respectively) and peripheral oedema with amlodipine (1.5% withdrawals).

CONCLUSIONS

In patients with stable angina, ivabradine has comparable efficacy to amlodipine in improving exercise tolerance, a superior effect on the reduction of rate-pressure product (a surrogate marker of myocardial oxygen consumption) and similar safety.

Current strategies for the prevention of angina in patients with stable coronary artery disease

PURPOSE OF REVIEW

Angina pectoris affects at least 6.6 million people in the US and approximately 400,000 new cases of stable angina occur each year. Angina may be one of the first signs of ischemic heart disease, although it is likely not causally related to the likelihood of plaque rupture leading to an acute coronary syndrome. Modalities for treatment of angina should be used maximally to improve quality of life and decrease cardiovascular morbidity and mortality. The current recommended pharmacologic and invasive approaches, as well as novel therapies, are reviewed.

RECENT FINDINGS

Antiischemic agents, including beta-blockers, nitrates and calcium channel blockers, remain the mainstay in the prevention of angina. Revascularization via percutaneous interventions or coronary bypass surgery are appropriate in specific cases or when medical treatment fails. Noninvasive treatment options for refractory angina, metabolic agents, and vasodilator therapies are adding to the armamentarium to prevent and treat angina.

SUMMARY

A multifaceted approach is optimal to address the prevention of angina. Once angina is recognized, there are many modalities that lessen the incidence of daily life-induced and exercise-induced angina and ischemia. Angina management is best addressed by pharmacologic and lifestyle interventions.

Effects of amlodipine on ischemia after percutaneous transluminal coronary angioplasty: secondary results of the Coronary Angioplasty Amlodipine Restenosis (CAPARES) Study

BACKGROUND

Despite successful coronary angioplasty (PTCA), patients may have ischemia after the procedure because of the overall coronary disease and luminal renarrowing at the lesion sites. The aim of this study was to examine the effects of the calcium-channel blocker amlodipine on post-PTCA ischemia.

METHODS

In a prospective, double-blind design, patients were randomized to receive 10 mg of amlodipine or placebo 2 weeks before angioplasty. Exercise tests and 48-hour ambulatory electrocardiography recordings were performed in 405 patients, 2 weeks before and 2 and 20 weeks (early and late) after PTCA.

RESULTS

There were no differences in clinical and angiographic baseline characteristics between the treatment groups. Ischemia and angina were equally distributed before PTCA, and no difference in restenosis was found between the groups at follow-up. The incidence of angina was significantly lower in the amlodipine group compared with the placebo group both early and late after PTCA (P =.04 and.03). Exercise-induced ischemia was reduced by 40% (P =.009) early and 34% (P =.02) late after PTCA in the amlodipine group, and ischemia on ambulatory electrocardiography was reduced by 18% early and 28% late after PTCA compared with placebo (P =.06 and P =.009).

CONCLUSION

Ischemia and angina occurred after successful PTCA and were significantly reduced by amlodipine.

Amlodipine versus Angiotensin-receptor blockers for nonhypertension indications

OBJECTIVE

To review the efficacy and safety data of amlodipine and the angiotensin-receptor blockers (ARBs), focusing on heart failure, angina, percutaneous coronary intervention (PCI), and renal protection.

DATA SOURCE

A MEDLINE search (1966-December 2001) was completed using amlodipine, angiotensin-receptor antagonist, losartan, valsartan, candesartan, and telmisartan as key words. English-language articles were identified and included.

STUDY SELECTION AND DATA EXTRACTION

All identified articles were evaluated. Articles representative of the subject matter of our review were included.

DATA SYNTHESIS

Amlodipine and the ARBs lower blood pressure to a similar extent. Amlodipine is an effective antianginal agent, whereas ARBs are not. However, amlodipine is not effective in the treatment of heart failure; ARBs may be useful in this setting. ARBs are also effective in preserving renal function and may provide some protection from restenosis in patients who have had a PCI. The ARBs may also be useful in preventing both diabetic and nondiabetic nephropathy.

CONCLUSIONS

Concomitant disease states should be considered when choosing between an ARB and amlodipine for the management of hypertension.

Restenosis and clinical outcome in patients treated with amlodipine after angioplasty: results from the Coronary AngioPlasty Amlodipine REStenosis Study (CAPARES)

OBJECTIVES

Our intent was to investigate the effect of the dihydropyridine calcium channel blocker amlodipine on restenosis and clinical outcome in patients undergoing percutaneous transluminal coronary angioplasty (PTCA).

BACKGROUND

Amlodipine has sustained vasodilatory effects and relieves coronary spasm, which may reduce luminal loss and clinical complications after PTCA.

METHODS

In a prospective, double-blind design, 635 patients were randomized to 10 mg of amlodipine or placebo. Pretreatment with the study drug started two weeks before PTCA and continued until four months after PTCA. The primary angiographic end point was loss in minimal lumen diameter (MLD) from post-PTCA to follow-up, as assessed by quantitative coronary angiography (QCA). Clinical end points were death, myocardial infarction, coronary artery bypass graft surgery and repeat PTCA (major adverse clinical events).

RESULTS

Angioplasty was performed in 585 patients (92.1%); 91 patients (15.6%) had coronary stents implanted. Follow-up angiography suitable for QCA analysis was done in 236 patients in the amlodipine group and 215 patients in the placebo group (per-protocol group). The mean loss in MLD was 0.30 +/- 0.45 mm in the amlodipine group versus 0.29 +/- 0.49 mm in the placebo group (p = 0.84). The need for repeat PTCA was significantly lower in the amlodipine versus the placebo group (10 [3.1%] vs. 23 patients [7.3%], p = 0.02, relative risk ratio [RR]: 0.45, 95% confidence interval [CI]: 0.22 to 0.91), and the composite incidence of clinical events (30 [9.4%] vs. 46 patients (14.5%), p = 0.049, RR: 0.65, CI: 0.43 to 0.99) within the four months follow-up period (intention-to-treat analysis).

CONCLUSIONS

Amlodipine therapy starting two weeks before PTCA did not reduce luminal loss, but the incidence of repeat PTCA and the composite major adverse clinical events were significantly reduced during the four-month follow-up period after PTCA with amlodipine as compared with placebo.

Effect of amlodipine on exercise-induced platelet activation in patients affected by chronic stable angina

BACKGROUND

Literature concerning exercise-induced platelet activation in chronic stable angina is somewhat confusing. The reason lies in the type of exercise as well as in methodological problems. A powerful, recently introduced procedure to detect platelet activation is flow cytometry. Platelet response to activating factors is mediated by calcium uptake; however, calcium antagonist effect on platelet activity is still unclear.

HYPOTHESIS

The study was undertaken to investigate exercise-induced platelet activation before and after treatment with amlodipine in chronic stable angina.

METHODS

Twenty patients with chronic stable angina were entered into the study. Each subject underwent a symptom-limited cycloergometer stress test following a washout period of 2 weeks. Blood samples were collected before and immediately after exercise. All subjects were then randomized into two groups of 10 patients each, with Group 1 and Group 2 taking amlodipine 10 mg/day, and placebo for 4 weeks, respectively. They subsequently underwent a second exercise stress test, and blood samples were obtained before and immediately after exercise. Flow-cytometric evaluation of platelet activity was performed in order to recognize GMP-140 expression on platelet membrane.

RESULTS

Strenuous exercise induced a significant increase in platelet activation in all subjects prior to therapy. No significant differences were observed in platelet activity at rest between Groups 1 and 2, whereas a significant decrease in exercise-induced platelet activation was demonstrated in Group 1 compared with Group 2.

CONCLUSION

Our data provide evidence of the favorable effect of amlodipine on exercise-induced platelet activation in patients affected by chronic stable angina.

"Traditional" medical therapy for unstable angina. How important? How to use?

Unstable angina comprises a heterogeneous population of patients who present with a wide spectrum of underlying pathophysiology. The traditional treatment of these patients is based on both evidenced-based medicine as well as clinical experience. Despite the large population of patients admitted with this diagnosis, the scientific literature regarding its treatment is scarce. Therefore, the management of patients with unstable angina relies heavily on the clinical skills of the physician. One of the most important steps in this process involves risk stratification, especially in the current environment of cost containment. Those patients who are at low risk for adverse outcomes can be treated and evaluated safely as outpatients. Patients at high or moderate risk, however, should be treated intensively as inpatients. Although there appear to be many new promising therapies for unstable angina on the horizon, the traditional therapies still have a place. The use of aspirin in this population is well supported by the literature and appears to have a positive effect on mortality and cardiovascular events. The other traditional therapies, however, are not as well supported by the literature. They do appear to benefit the patient in terms of reducing symptoms, but their effects on reducing mortality and cardiovascular events are not clear. Therefore, the goal of medical therapy in this patient population should be to stabilize them so that they can proceed with an appropriate risk stratification procedure as soon as possible. This is especially true with performing coronary angiography or interventions because the risk of procedural complications is higher in patients with unstable angina and ongoing symptoms.

Amlodipine in patients with stable angina pectoris treated with beta-blockers. Double-blind comparison with placebo

In order to assess additional anti-ischaemic effects of amlodipine (AML) on coronary artery disease (CAD) treated with beta-blockers, 32 patients with CAD, verified on angiograms, and stable angina were randomized to receive 5 mg/day of AML or placebo, increasing to 10 mg/day after 2 weeks. Baseline recording of 24-h ambulatory ECG and blood pressure, echocardiography and bicycle exercise test was repeated after treatment for 2 weeks and for 6 weeks. Reduction of ambulatory ischaemia was not significantly greater with AML than with placebo. In exercise tests the time to 0.1 mV ST segment depression and the total exercise time remained unaltered. Blood pressure was reduced by 10 mg AML. The total variability and the very low frequency component of heart rate were reduced after both doses. The clinical significance of the possible unfavourable change in autonomic modulation of the heart in CAD patients is not known.

Molecular pharmacology of UK-118, 434-05, a permanently charged amlodipine analog

We studied the effects of UK-118, 434-05, a permanently charged form of amlodipine, on recombinant smooth muscle and cardiac L-type calcium channels to determine the distinct modulatory properties of the ionized form of amlodipine. We found that the short distance between the permanent charge group and the active dihydropyridine (DHP) ring of UK-118, 434-05 reduces the potency of this compound as an inhibitor of smooth muscle (alpha(1c-b)) L-type channels, and is similar to the effects of other charged DHP derivatives on cardiac (alpha(1c-a)) L-type channels. However, we found surprisingly that the tonic block of cardiac (alpha(1c-a)) L-type channels was more pronounced than the tonic block of smooth muscle (alpha(1c-b)) L-type channels. This result contrasts with the previously reported subunit-specificity of neutral DHP compounds, and suggests that interactions between the amlodipine charge group and site(s) on the L-type channel alpha1 subunit distinguish the action of charged from neutral DHPs and may contribute to amlodipine's unique pharmacological profile.

Felodipine and amlodipine in stable angina pectoris: results of a randomized double-blind crossover trial

A randomized, double-blind, crossover study tested the antiischemic and antianginal efficacy of felodipine, extended-release 5-10 mg, versus amlodipine, 5-10 mg once daily. Fifty-two patients with documented exercise-induced angina pectoris and myocardial ischemia during 24-h electrocardiographic monitoring were included in the study. Forty-seven patients completed the 8-week treatment period, whereas five patients withdrew from the study. The mean number of ischemic episodes/24 h was reduced from 19.9 at baseline to 2.3 during amlodipine and to 2.4 during felodipine; the total duration of ischemic episodes decreased from 69.8 min/24 h to 15.2 min and 15.5 min during amlodipine and felodipine, respectively (for both variables, p = 0.83 and p = 0.53 between treatments, and for both treatments, p < 0.001 compared with baseline). Eighteen (38%) patients receiving amlodipine and 19 (40%) patients receiving felodipine showed no ST-segment depression during treatment. Maximal ST-depression was reduced from an average of 2.1 mm to 1.1 and 1.2 mm on amlodipine and felodipine, respectively (p = 0.68 between treatments and p < 0.001 compared with baseline). Mean heart rate remained unchanged compared with baseline. Anginal attacks were reduced from 16.4/week at baseline to 4.7/week with amlodipine and to 4.3/week with felodipine (p = 0.26 between treatments, and p < 0.001 vs. baseline). Accordingly, nitrate consumption was reduced from 14.7 capsules per week to 4.0 and 3.8 with amlodipine and felodipine, respectively (p = 0.40 between treatments, and p < 0.001 compared with baseline). Adverse reactions were infrequent and distributed similarly between the two treatments. It is concluded that both drugs effectively reduced ischemic episodes and anginal attacks and were well tolerated in patients with stable angina pectoris. There was no evidence that the two regimens were different in their antiischemic and antianginal properties.

Nifedipine gastrointestinal therapeutic system versus atenolol in stable angina pectoris. The Netherlands Working Group on Cardiovascular Research (WCN)

The gastrointestinal therapeutic system formulation of nifedipine enables a once-daily dosing resulting in predictable, relatively constant plasma concentrations. To evaluate the efficacy and safety of this formulation and to compare this with the beta-blocker atenolol, we conducted a double-blind, randomised, multi-centre study in 129 male patients with documented exercise induced angina pectoris. After 4 weeks' treatment, nifedipine (60 mg), improved time to onset of 0.1 mV ST-segment depression from 536 s by 72 +/- 117s, time to onset of pain from 619 s by 56 +/- 120 s, and total exercise time from 685 s by 40 +/- 88 s. Atenolol 100 mg, had a comparable effect, time to onset of 0.1 mV ST-segment depression improved from 496 s by 53 +/- 129 s, time to onset of pain from 572 s by 57 +/- 118 s, and total exercise time from 653 s by 33 +/- 99 s. Between group analysis revealed no statistically significant differences for these exercise parameters. Atenolol, but not nifedipine, significantly reduced heart rate and systolic blood pressure at rest and during exercise (P < 0.001 between groups), indicating different modes of action of the drugs. With regard to safety, both drugs were generally well tolerated. There were significantly (P = 0.01) more vasodilation related side effects with nifedipine. These data demonstrate that gastrointestinal therapeutic system formulation of nifedipine and atenolol as once-daily monotherapy are equally effective and safe, but with different effects on exercise parameters.