Cardioprotective and Antianginal Efficacy of Nicorandil: A Comprehensive Review

ABSTRACT

Angina pectoris remains a significant burden despite advances in medical therapy and coronary revascularization. Many patients (up to 30%) with angina have normal coronary arteries, with coronary microvascular disease and/or coronary artery vasospasm being major drivers of the myocardial demand-supply mismatch. Even among patients revascularized for symptomatic epicardial coronary stenosis, recurrent angina remains highly prevalent. Medical therapy for angina currently centers around 2 disparate goals, viz secondary prevention of hard clinical outcomes and symptom control. Vasodilators, such as nitrates, have been first-line antianginal agents for decades, along with beta-blockers and calcium channel blockers. However, efficacy in symptoms control is heterogenous, depending on underlying mechanism(s) of angina in an individual patient, often necessitating multiple agents. Nicorandil (NCO) is an antianginal agent first discovered in the late 1970s with a uniquely dual mechanism of action. Like a typical nitrate, it mediates medium-large vessel vasodilation through nitric oxide. In addition, NCO has adenosine triphosphate (ATP)-dependent potassium channel agonist activity (K ATP ), mediating microvascular dilatation. Hence, it has proven effective in both coronary artery vasospasm and coronary microvascular disease, typically challenging patient populations. Moreover, emerging evidence suggests that cardiomyocyte protection against ischemia through ischemic preconditioning may be mediated through K ATP agonism. Finally, there is now fairly firm evidence in favor of NCO in terms of hard event reduction among patients with stable coronary artery disease, following myocardial infarction, and perhaps even among patients with congestive heart failure. This review aims to summarize the mechanism of action of NCO, its efficacy as an antianginal, and current evidence behind its impact on hard outcomes. Finally, we review other cardiac and emerging noncardiac indications for NCO use.

The Safety of Nicorandil Therapy and the Relationship with Treatment Adherence in Patients with Stable Angina Pectoris (According to the NIKEA Observational Study)

The working group of the NIKEA study: Reznik I.I. (Ekaterinburg), Akulina E.N. (Ekaterinburg), Ezhov A.V. (Izhevsk), Shinkareva S.I. (Izhevsk), Grebnev S.A. (Izhevsk), Skibitsky V.V. (Krasnodar), Kudryashov E.A. (Krasnodar), Fendrikova A.V. (Krasnodar), Skibitsky A.V. (Krasnodar), Matyushin G.V. (Krasnoyarsk), Nemik D.B. (Krasnoyarsk), Pitaev R.R. (Krasnoyarsk), Altaev V.D. (Krasnoyarsk), Samokhvalov E.V. (Krasnoyarsk), Stolbikov Y.Y.. (Krasnoyarsk), Voronina V.P. (Moscow), Lerman O.V. (Moscow), Gaisenok O.V. (Moscow), Dmitrieva N.A. (Moscow), Zagrebelny A.V. (Moscow), Zakharova A.V. (Moscow), Balashov I.S. (Moscow), Leonov A.S. (Moscow), Sladkova T.A. (Moscow), Zelenova T.I. (Moscow), Shestakova G.N. (Moscow), Kolganova E.V. (Moscow), Maksimova M.A. (Moscow), Kuimov A.D. (Novosibirsk), Moskalenko I.V. (Novosibirsk), Shurkevich A.A. (Novosibirsk), Nechaeva G.I. (Omsk), Loginova E.N. (Omsk), Gudilin V.A. (Omsk), Mitroshina T.N. (Orel), Zhuravleva L.L. (Orel), Lobanova G.N. (Orel), Luneva M.M. (Orel), Libis R.A. (Orenburg), Kondratenko V.Yu. (Orenburg), Chesnikova A.I. (Rostov-on-Don), Kalacheva N.M. (Rostov-on-Don), Kolomatskaya O.O. (Rostov-on-Don), Dubishcheva N.F. (Rostov-on-Don), Romadina G.V. (Rostov-on-Don), Chugunova I.B. (Rostov-on-Don), Skarzhinskaya N.S. (Rostov-on-Don), Dobrynina N.V. (Ryazan), Yakushin S.S. (Ryazan), Bulanov A.V. (Ryazan), Trofimova Ya.M. (Ryazan), Nikolaeva A.S. (Ryazan), Sokolova L.A. (St. Petersburg), Savinova E.B. (St. Petersburg), Ievskaya E.V. (St. Petersburg), Vasilyeva L.B. (St. Petersburg), Gomova T.A. (Tula), Zubareva L.A. (Tula), Berberfish L.D. (Tula), Gorina G.I. (Tula), Nadezhkina K.N. (Tula), Yunusova K.N. (Tula), Nikitina V.F. (Tula), Dabizha V.G. (Tula), Renko I.E. (Tula), Soin I.A. (Tula)

Aim. To analyze the adverse events (AEs) of nicorandil therapy based on the results of an observational study of NIKEA, to assess the relationship between the occurrence of AEs treatment and adherence to it in patients with stable angina pectoris.

Material and methods. The study included 590 people who had nicorandil added to the basic therapy of coronary artery disease (CAD). The followup period averaged 21 months. There were two visits of 1 and 3 months of follow-up (V1 and V3), and after 21 months, by telephone contact (PhC21), it was possible to obtain information about 524 patients (89% response), 509 of whom were alive. Information about the treatment adherence and AEs of nicorandil was collected during V1, V3 and at PhC21.

Results. Out of 590 people, 402 (68.1%) patients started treatment with nicorandil. During 21 months of follow-up, 35 AEs were registered in 34 patients. There were no serious AEs associated with taking medications in the study. The most frequent AEs of treatment with nicorandil were hypotension and headache, which led to non-adherence to therapy in 94% and 42% of cases, respectively. The majority of AEs (24 out of 35) occurred during the first three months of nicorandil treatment. Both any AEs of drug therapy and AEs of nicorandil therapy, on average, increase the chance of non-adherence to the recommended treatment by 3 times (p=0.004).

Conclusion. The results of the NIKEA study confirmed the good safety of nicorandil in patients with stable angina pectoris, the absence of serious adverse events associated with taking this antianginal drug. The most frequent nicorandil AEs were hypotension and headache. Any AEs of therapy increase the chance of patients' non-adherence by 3 times.

A Long-Term Study Evaluating the Effects of Nicorandil Treatment on Duchenne Muscular Dystrophy-Associated Cardiomyopathy in mdx Mice

BACKGROUND

Duchenne muscular dystrophy (DMD) is a neuromuscular disease caused by dystrophin gene mutations affecting striated muscle. Due to advances in skeletal muscle treatment, cardiomyopathy has emerged as a leading cause of death. Previously, nicorandil, a drug with antioxidant and nitrate-like properties, ameliorated cardiac damage and improved cardiac function in young, injured mdx mice. Nicorandil mitigated damage by stimulating antioxidant activity and limiting pro-oxidant expression. Here, we examined whether nicorandil was similarly cardioprotective in aged mdx mice.

METHODS AND RESULTS

Nicorandil (6 mg/kg) was given over 15 months. Echocardiography of mdx mice showed some functional defects at 12 months compared to wild-type (WT) mice, but not at 15 months. Disease manifestation was evident in mdx mice via treadmill assays and survival, but not open field and grip strength assays. Cardiac levels of SOD2 and NOX4 were decreased in mdx vs. WT. Nicorandil increased survival in mdx but did not alter cardiac function, fibrosis, diaphragm function or muscle fatigue.

CONCLUSIONS

In contrast to our prior work in young, injured mdx mice, nicorandil did not exert cardioprotective effects in 15 month aged mdx mice. Discordant findings may be explained by the lack of cardiac disease manifestation in aged mdx mice compared to WT, whereas significant cardiac dysfunction was previously seen with the sub-acute injury in young mice. Therefore, we are not able to conclude any cardioprotective effects with long-term nicorandil treatment in aging mdx mice.

The Efficacy and Safety of Nicorandil for Periprocedural Myocardial Injury in Patients Undergoing PCI: A Meta-Analysis

Purpose

To evaluate the efficacy and safety of nicorandil for periprocedural myocardial injury in patients undergoing PCI through meta-analysis of randomized controlled trials.

Methods

We analyzed the clinical data of patients including the incidence of periprocedural myocardial injury (PMI) and major adverse cardiovascular events (MACE) from selected articles. RCTs were retrieved from medical literature databases. RR and 95% confidence intervals (CI) were calculated to compare the endpoints.

Results

In total, 15 articles (16 trial comparisons) were retrieved which contained 2221 patients. In general, 1130 patients (50.9%) were randomized to the experimental group, whereas 1091 patients (49.1%) were randomized to the control group. The result showed that nicorandil significantly reduced the incidence of PMI and MACE after PCI compared to the control group.

Conclusions

Overall, early use of nicorandil in patients undergoing percutaneous coronary intervention (PCI) was associated with a significant reduction of PMI and MACE.

Angina and Its Management

Angina pectoris is defined as substernal chest pain, pressure, or discomfort that is typically exacerbated by exertion and/or emotional stress, lasts greater than 30 to 60 seconds, and is relieved by rest and nitroglycerin. There are approximately 10 million people in the United States who have angina, and there are over 500 000 cases diagnosed per year. Several studies now show that angina itself is a predictor of major adverse cardiac events. In addition, angina is a serious morbidity that impedes quality of life and should be treated. In the United States, pharmacologic therapy for angina includes β-blockers, nitrates, calcium channel blockers, and the late sodium current blocker ranolazine. In other countries, additional pharmacologic agents include trimetazidine, ivabradine, nicorandil, fasudil, and others. Revascularization is indicated in certain high-risk individuals and also has been shown to improve angina. However, even after revascularization, a substantial percentage of patients return with recurrent or continued angina, requiring newer and better therapies. Treatment for refractory angina not amenable to usual pharmacologic therapies or revascularization procedures, includes enhanced external counterpulsation, transmyocardial revascularization, and stem cell therapy. Angina continues to be a significant cause of morbidity. Therapy should be geared not only to treating the risk factors for atherosclerotic disease and improving survival but should also be aimed at eliminating or reducing the occurrence of angina and improving the ability of patients to be active.

Management standards for stable coronary artery disease in India

Coronary artery disease (CAD) is one of the important causes of cardiovascular morbidity and mortality globally, giving rise to more than 7 million deaths annually. An increasing burden of CAD in India is a major cause of concern with angina being the leading manifestation. Stable coronary artery disease (SCAD) is characterised by episodes of transient central chest pain (angina pectoris), often triggered by exercise, emotion or other forms of stress, generally triggered by a reversible mismatch between myocardial oxygen demand and supply resulting in myocardial ischemia or hypoxia. A stabilised, frequently asymptomatic phase following an acute coronary syndrome (ACS) is also classified as SCAD. This definition of SCAD also encompasses vasospastic and microvascular angina under the common umbrella.

Vasodilator Therapy: Nitrates and Nicorandil

Nitrates have been used to treat symptoms of chronic stable angina for over 135 years. These drugs are known to activate nitric oxide (NO)-cyclic guanosine-3',-5'-monophasphate (cGMP) signaling pathways underlying vascular smooth muscle cell relaxation, albeit many questions relating to how nitrates work at the cellular level remain unanswered. Physiologically, the anti-angina effects of nitrates are mostly due to peripheral venous dilatation leading to reduction in preload and therefore left ventricular wall stress, and, to a lesser extent, epicardial coronary artery dilatation and lowering of systemic blood pressure. By counteracting ischemic mechanisms, short-acting nitrates offer rapid relief following an angina attack. Long-acting nitrates, used commonly for angina prophylaxis are recommended second-line, after beta-blockers and calcium channel antagonists. Nicorandil is a balanced vasodilator that acts as both NO donor and arterial K(+) ATP channel opener. Nicorandil might also exhibit cardioprotective properties via mitochondrial ischemic preconditioning. While nitrates and nicorandil are effective pharmacological agents for prevention of angina symptoms, when prescribing these drugs it is important to consider that unwanted and poorly tolerated hemodynamic side-effects such as headache and orthostatic hypotension can often occur owing to systemic vasodilatation. It is also necessary to ensure that a dosing regime is followed that avoids nitrate tolerance, which not only results in loss of drug efficacy, but might also cause endothelial dysfunction and increase long-term cardiovascular risk. Here we provide an update on the pharmacological management of chronic stable angina using nitrates and nicorandil.

Preparative isolation and high-resolution mass identification of 10 stressed study degradants of nicorandil tablets

Nicorandil is a potent drug with a dual mechanism of action which results in its wide application in treating angina patients. Since the literature review showed no single preparative method for isolation and liquid chromatography-mass spectrometry (LC-MS) compatible [high-performance liquid chromatography (HPLC) or ultra performance liquid chromatography (UPLC)] method for identification for the impurities generated in process and by force degradation was reported. Thus an attempt was made to develop a single preparative method for isolation and HPLC and UPLC methods for identification of impurities of nicorandil in tablet dosage form. Ten degradants were found in the formulated drug under the stress conditions, [40°C/75% relative humidity for 2 months] in an LC-MS compatible method. A cost effective and high-throughput simple gradient preparative HPLC method was developed with a runtime of 30 min to isolate all the degradants. The method is capable and can be used to isolate further degradants. To detect these degradants, rapid and effecient HPLC and UPLC methods were developed and the same were identified by UPLC-time of flight mass spectrometry (TOF MS). The crux of this work involves a single preparative isolation method and UPLC identification method for all degradants with a very short runtime, i.e., 13.8 min, and, furthermore, the method has the potential to separate a wide range of degradants.

Stable angina pectoris: antianginal therapies and future directions

Advances in pharmacotherapy for stable angina have produced a wide choice of drugs with various mechanisms of action, potentially enabling individualized, patient-specific treatment strategies to be developed. In this Review, the various treatment options for patients with stable angina are discussed. Data from randomized, clinical trials of established and novel drugs are reviewed, with particular emphasis on the proposed mechanisms of action, benefits of therapy, and adverse-effect profiles. The role of coronary revascularization in conjunction with optimal medical therapy as a treatment strategy is discussed, although drug therapy might reduce the need for prompt revascularization if the procedure is being considered solely for the purpose of alleviating angina. Finally, trials to investigate stimulation of angiogenesis using growth-factor, gene, and cell therapy are used to illustrate the challenges of chemically inducing the growth of adequate, durable blood vessels.