Ranolazine, a novel agent for chronic stable angina

Clinically approved representative small-molecule drugs for cardiopathy therapy

The application of therapeutic agents for cardiopathy has brought about significant advancements in the treatment of cardiovascular diseases. The intervention of small-molecule drugs has led to substantial reductions in morbidity and mortality rates, along with decreased utilization of healthcare resources. However, current treatment modalities do not exhibit uniform efficacy across all patients, and the emergence of drug resistance poses a significant challenge to further therapeutic efforts. Additionally, chronic administration of these drugs can result in toxicities, adding complexity to long-term management. This review focuses on the application of clinically approved small-molecule drugs for the treatment of cardiopathy, covering major classes such as angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, β-blockers, and sodium-glucose co-transporter 2 inhibitors. The review provides an in-depth analysis of their synthetic routes, mechanisms of action, and roles in cardiopathy treatment. It also offers perspectives on future directions in the development of next-generation cardioprotective agents, aiming to optimize therapeutic strategies for cardiovascular disease management.

Role of Ranolazine in cardiovascular disease and diabetes: Exploring beyond angina

Ranolazine was FDA approved for chronic angina in 2006. Since then, there has been extensive research involving this drug. The mechanism of action, debatable at the time of approval, has been demonstrated. Ranolazine acts via inhibition of late sodium channel current in the myocardium. This acts by lowering abnormally high cytosolic calcium levels. Other possible clinical applications of Ranolazine have also been explored. Out of many lines of investigation, its effects in atrial fibrillation, especially post-CABG and recurrent atrial fibrillation show promise. It has also shown definite HbA1c lowering effects when used in diabetics with coronary artery disease. Other possible indications for the drug include pulmonary arterial hypertension, diastolic dysfunction and chemotherapy-induced cardiotoxicity. This review aims to summarize major research regarding Ranolazine in potential applications beyond chronic angina. There are few dedicated large, randomized, phase III trials exploring the newer effects of Ranolazine. There are a few such trials underway, but more are needed.

Antagonism of Nav channels and α1-adrenergic receptors contributes to vascular smooth muscle effects of ranolazine

Ranolazine is a recently developed drug used for the treatment of patients with chronic stable angina. It is a selective inhibitor of the persistent cardiac Na⁺ current (I_Na), and is known to reduce the Na⁺-dependent Ca²⁺ overload that occurs in cardiomyocytes during ischemia. Vascular effects of ranolazine, such as vasorelaxation,have been reported and may involve multiple pathways. As voltage-gated Na⁺ channels (Na_v) present in arteries play a role in contraction, we hypothesized that ranolazine could target these channels. We studied the effects of ranolazine in vitro on cultured aortic smooth muscle cells (SMC) and ex vivo on rat aortas in conditions known to specifically activate or promote I_Na. We observed that in the presence of the Na_v channel agonist veratridine, ranolazine inhibited I_Na and intracellular Ca²⁺ calcium increase in SMC, and arterial vasoconstriction. In arterial SMC, ranolazine inhibited the activity of tetrodotoxin-sensitive voltage-gated Na_v channels and thus antagonized contraction promoted by low KCl depolarization. Furthermore, the vasorelaxant effects of ranolazine, also observed in human arteries and independent of the endothelium, involved antagonization of the α₁-adrenergic receptor. Combined α₁-adrenergic antagonization and inhibition of SMCs Na_v channels could be involved in the vascular effects of ranolazine.

The contribution of mechanistic understanding to phenotypic screening for first-in-class medicines

The level of mechanistic understanding required for drug discovery is a central feature of most strategies. However, an understanding of mechanism is not required for regulatory approval. This paradox is particularly relevant to the role of phenotypic assays in drug discovery. A recent analysis revealed that phenotypic drug discovery strategies were more successful for first-in-class medicines, whereas target-based molecular strategies were more successful for followers (Nat. Rev. Drug Discov. 2011, 10, 507-519). The rationale for the success of phenotypic screening was the unbiased identification of the molecular mechanism of action. In this follow-up analysis, the format and mechanistic information used to establish the phenotypic assays that led to the first-in-class small-molecule new molecular entities approved by the U.S. Food and Drug Administration between 1999 and 2008 were analyzed and compared with those approved in 2012. Not surprisingly, some level of mechanistic understanding was used to select the assay formats and chemicals screened. It is concluded that mechanism takes on different connotations depending on context and perspective and that a target need not always be the exclusive definition of mechanism.

How were new medicines discovered?

Preclinical strategies that are used to identify potential drug candidates include target-based screening, phenotypic screening, modification of natural substances and biologic-based approaches. To investigate whether some strategies have been more successful than others in the discovery of new drugs, we analysed the discovery strategies and the molecular mechanism of action (MMOA) for new molecular entities and new biologics that were approved by the US Food and Drug Administration between 1999 and 2008. Out of the 259 agents that were approved, 75 were first-in-class drugs with new MMOAs, and out of these, 50 (67%) were small molecules and 25 (33%) were biologics. The results also show that the contribution of phenotypic screening to the discovery of first-in-class small-molecule drugs exceeded that of target-based approaches - with 28 and 17 of these drugs coming from the two approaches, respectively - in an era in which the major focus was on target-based approaches. We postulate that a target-centric approach for first-in-class drugs, without consideration of an optimal MMOA, may contribute to the current high attrition rates and low productivity in pharmaceutical research and development.

Ranolazine for the management of coronary artery disease

BACKGROUND

Despite coronary revascularization and standard antianginal therapy, many patients continue to experience symptoms of stable angina and progression of their disease. Ranolazine is a new class of antianginal agent. Unlike standard antianginal agents, it alters glucose and fatty acid metabolism for a different approach to the management of coronary artery disease.

OBJECTIVE

This article discusses the clinical pharmacology of ranolazine and its use in the management of chronic stable angina.

METHODS

Peer-reviewed articles and abstracts were identified from MEDLINE and the Current Contents database (both from 1966 to September 20, 2006) using the search terms ranolazine, angina, pharmacokinetics, and pharmacology. Citations from available articles were reviewed for additional references. Abstracts presented at recent professional meetings were also reviewed.

RESULTS

Ranolazine is a cell membrane inhibitor of the late sodium current. Extended-release ranolazine was recently approved in the United States for the treatment of chronic angina. Ranolazine is metabolized in the liver by the cytochrome P-450 (CYP) 3A4 system. Because of its potential to prolong corrected QT (QTc) intervals, ranolazine should not be used in patients with hepatic impairment, those with QTc prolongation, or those taking drugs known to prolong QTc intervals or drugs that are potent CYP 3A4 inhibitors. Other adverse effects of ranolazine include dizziness, headache, constipation, and nausea. Placebo-controlled clinical studies performed to date have found that sustained-release ranolazine 500 to 1500 mg PO BID was associated with significantly increased time to onset of angina (range of increase, 27.0-144.0 s; P < 0.05 [varied among studies]), exercise duration (range of increase, 23.8-99.0 s; P < 0.05 [varied among studies] ), and time to 1-mm ST depression (range of increase, 27.6-146.2 s; P < 0.05 [varied among studies]). In addition, exercise duration was found to be significantly longer with ranolazine compared with atenolol (453 vs 430 s; P = 0.006).

CONCLUSIONS

Ranolazine is a new antianginal agent that is effective in the management of chronic angina. Its unique mechanism of action warrants further study in other cardiovascular conditions such as heart failure and arrhythmias. Ongoing studies will address whether ranolazine can reduce clinical end points such as cardiovascular death and myocardial infarction.

The Role of Ranolazine in the Management of Chronic Stable Angina

This continuing feature will update readers on recent developments in cardiovascular pharmacotherapy. Cardiovascular disease remains the number one killer in the United States, and more clinical outcome trials have been conducted in cardiology than in any other field of medicine. Given this rapidly expanding knowledge base, pharmacists can have a significant impact on prevention and treatment—if they keep current with developments in drug therapy.