Ranolazine

Introduction Overview

Generic Name

ranolazine

Brand Name

Aspruzyo Sprinkle, Ranexa

Dosage Form

oral granule extended release, oral tablet extended release

Drug Class

Antianginal agents

Pharmacokinetics

Absorption:
Ranolazine exhibits moderate oral bioavailability and is administered as an extended-release formulation to maintain therapeutic plasma concentrations throughout the dosing interval. It is absorbed primarily in the gastrointestinal tract, with peak plasma concentrations typically reached within 2 to 5 hours post-administration. Food intake does not significantly affect the absorption of ranolazine tablets, thus it can be given with or without food. In the case of granules, these are mixed with soft foods and are suitable for patients with swallowing difficulties or those requiring feeding tubes. The extended release formulation allows for twice daily dosing, enhancing patient compliance compared to immediate release forms.

Distribution:
Ranolazine has a large volume of distribution, indicative of extensive tissue binding. It is approximately 62% bound to plasma proteins, mainly albumin. Ranolazine distributes well into peripheral tissues, although specific tissue distribution data remain limited. The drug crosses cell membranes by passive diffusion, and its distribution characteristics enable it to reach myocardial tissues where it exerts its pharmacological effects. Factors such as renal impairment may alter distribution volume, necessitating careful clinical monitoring.

Metabolism:
Ranolazine undergoes extensive hepatic metabolism, predominantly via cytochrome P450 isoenzymes CYP3A4 and to a lesser extent CYP2D6. Multiple metabolites are produced, some of which are pharmacologically inactive. The inhibition or induction of these enzymes can significantly affect ranolazine plasma concentrations. For example, concomitant administration with strong CYP3A4 inhibitors (e.g., clarithromycin, ketoconazole) can elevate ranolazine levels, increasing the risk of adverse effects. Conversely, CYP3A4 inducers (e.g., rifampin, carbamazepine) may reduce efficacy by lowering plasma concentrations.

Elimination:
Approximately 75% of absorbed ranolazine is excreted in the urine, mainly as metabolites, with less than 5% excreted unchanged. The remainder is eliminated via feces. The drug's elimination half-life ranges between 7 and 12 hours, supporting twice daily dosing. Renal impairment can lead to increased systemic exposure, particularly in moderate to severe cases, and plasma concentrations should be monitored. Hepatic impairment, especially cirrhosis, greatly reduces metabolism, leading to drug accumulation and contraindicating ranolazine use in such patients. The pharmacokinetic profile necessitates dose adjustments in certain populations to avoid toxicity and maintain therapeutic efficacy.

Dosage Forms

Available Dosage Forms:
Ranolazine is available in the following extended-release oral dosage forms:
- Oral granule extended release: 500 mg and 1000 mg
- Oral tablet extended release: 500 mg and 1000 mg
The granule formulation is designed to be mixed with a tablespoon of soft food such as applesauce or yogurt and swallowed immediately without crushing or chewing; it can also be administered via feeding tube, providing flexibility for patients with swallowing difficulties.

Dosages for Adults and Adolescents:
The usual adult dose for chronic angina is 500 mg orally twice daily, which may be increased to 1000 mg twice daily based on clinical response and tolerability. The maximum recommended dose is 1000 mg twice daily. Dosage adjustments should be made cautiously with close monitoring.

Specific Patient Populations:
- Patients with hepatic impairment: Ranolazine is contraindicated in patients with cirrhosis due to markedly reduced metabolism and increased risk of adverse effects.
- Patients with renal impairment: Dose adjustments may be necessary in moderate to severe renal dysfunction to prevent accumulation.
- Geriatric patients: Dosing should be cautious with frequent monitoring due to age-related pharmacokinetic changes.
- Administration considerations: Granule formulation provides an alternative for patients unable to swallow tablets, with the option for feeding tube administration.

Clinical guidelines emphasize that ranolazine should only be used for chronic angina and is not intended for acute angina attacks. Combination therapy with other antianginal drugs is common, requiring careful monitoring and individualized dosing.

Mechanism Of Action

Ranolazine primarily exerts its antianginal effect by inhibiting the late phase of the inward sodium current (late INa) in cardiac myocytes. During ischemic conditions, this late sodium influx increases intracellular sodium concentration, which in turn elevates intracellular calcium via the sodium-calcium exchanger, leading to increased myocardial wall tension and decreased coronary blood flow. By selectively blocking late INa, ranolazine reduces intracellular sodium and calcium overload, leading to decreased ventricular wall stress and improved myocardial relaxation.

This action improves myocardial oxygen efficiency by diminishing myocardial ischemia without affecting heart rate or blood pressure significantly, distinguishing ranolazine from traditional antianginal agents such as beta-blockers or calcium channel blockers. Ranolazine's unique mechanism allows it to be used in combination with other antianginal therapies for additive benefits.

At the cellular level, ranolazine modulates ionic homeostasis, stabilizing the electrical activity of the myocardium, which reduces the occurrence of ischemic-induced arrhythmias. Clinical studies have demonstrated that ranolazine improves exercise tolerance and reduces anginal episodes without significant negative chronotropic or inotropic effects.

Comparatively, unlike nitrates or beta-blockers that primarily alter hemodynamic parameters, ranolazine targets the cellular ionic imbalance characteristic of ischemic myocardium. Research evidence supports ranolazine’s efficacy in chronic stable angina, emphasizing its role in patients who remain symptomatic despite conventional therapy.

Pharmacological Actions

Selective inhibition of late inward sodium current in cardiac myocytes.
Reduction of intracellular sodium and calcium overload during ischemia.
Improvement of myocardial relaxation and reduction of ventricular wall tension.
Enhancement of myocardial oxygen efficiency without significant hemodynamic changes.
Stabilization of cardiac electrical activity, reducing risk of ischemic arrhythmias.
No significant effect on heart rate or blood pressure, allowing combination with other agents.
Antianginal effect by decreasing myocardial ischemia and improving exercise tolerance.
Potential modulation of ion channels beyond late INa, contributing to antiarrhythmic properties.
Metabolized via CYP3A4 and CYP2D6, enabling consideration of drug interactions.
Extended-release formulation to maintain steady plasma concentrations.
Suitable for patients intolerant to hemodynamic altering agents.
No significant negative inotropic effect, preserving cardiac contractility.

Therapeutic Or Clinical Uses

Treatment of chronic stable angina in adults to reduce frequency of anginal attacks.
Adjunct therapy for angina in patients inadequately controlled by or intolerant to conventional antianginal agents such as beta-blockers or calcium channel blockers.
Improvement in exercise tolerance and reduction of angina-related symptoms.
Off-label potential use in certain arrhythmias due to ion channel modulation.
Management of chronic ischemic heart disease in patients with contraindications to hemodynamic agents.
Therapeutic option for patients with persistent angina despite optimization of other therapies.
Considered in combination with other antianginal medications for additive efficacy.
Used in patients where reduction of heart rate or blood pressure is undesirable.
Potential utility in patients with comorbid conditions limiting standard treatments.
Improvement in quality of life by reducing angina episodes and associated limitations.
Avoided in acute coronary syndromes or during acute anginal attacks due to delayed onset.

Side Or Adverse Effects

Nausea, commonly reported during initiation or dose escalation.
Constipation, likely related to gastrointestinal motility effects.
Headache, possibly due to vascular or central nervous system effects.
Dizziness or light-headedness, which may affect activities requiring alertness.
Palpitations, including fast or pounding heartbeats; may indicate arrhythmia.
Potential for prolongation of QT interval, increasing risk of torsades de pointes.
Allergic reactions including rash, hives, and swelling of face, lips, or throat.
Symptoms of kidney problems such as swelling, decreased urination, fatigue, or shortness of breath.
Confusion, hallucinations, or visual disturbances reported rarely in overdose or sensitive individuals.
Low blood pressure episodes, especially with concurrent antihypertensive therapy.
Rarely tremors or uncontrolled shaking in overdose cases.
Fatigue or asthenia as nonspecific side effect.
Potential for drug accumulation and toxicity in hepatic impairment.
Risk of dizziness is increased in elderly population, advising caution.
Possible drug intolerance necessitating discontinuation or dosage adjustment.

Precautions

Contraindicated in patients with cirrhosis of the liver due to impaired metabolism.
Use cautiously in patients with hepatic impairment to avoid drug accumulation.
Monitor patients with kidney disease for signs of toxicity and adjust dosing accordingly.
Screen for history of long QT syndrome as ranolazine may prolong QT interval.
Avoid use with strong CYP3A4 inhibitors or inducers to prevent altered plasma levels.
Assess concomitant medications to mitigate risk of drug interactions, especially with antifungals, macrolide antibiotics, protease inhibitors, and anticonvulsants.
Educate patients on avoiding grapefruit products to prevent increased ranolazine plasma concentration.
Consider the potential impact on patients with pre-existing arrhythmias or conduction abnormalities.
Advise patients about possibility of dizziness and avoidance of driving or hazardous activities until response is known.
Regular cardiac and renal function monitoring may be warranted during treatment.
Exercise caution when combining with other QT-prolonging drugs.
Pregnancy and breastfeeding safety not well established; use only if clearly needed.
Symptom monitoring required due to possible infrequent but serious side effects.
Avoid abrupt discontinuation; follow prescribed dosing to prevent recurrence of angina.
Instruct patients to report any symptoms suggestive of allergic reactions or cardiac arrhythmias immediately.

Warnings

Do not use ranolazine in patients with cirrhosis of the liver due to risk of accumulation and toxicity.
Risk of QT interval prolongation necessitates avoidance in patients with congenital long QT syndrome.
Concomitant use with strong CYP3A4 inhibitors and inducers is contraindicated or requires dose adjustment.
Potential for serious arrhythmias in susceptible individuals; monitor ECG if clinically indicated.
Avoid grapefruit juice and products as they may increase ranolazine plasma concentration leading to toxicity.
Use with caution in patients with moderate to severe renal impairment requiring dose adjustments.
Do not use during acute anginal attacks as efficacy onset is delayed.
Emergency medical attention required if signs of allergic reaction or serious cardiac events occur.
Risk of dizziness and syncope in patients leading to potential injury from falls.
Avoid in pregnancy unless benefits outweigh risks due to lack of well-controlled studies.
Potential drug interactions with multiple commonly used medications; consult healthcare providers.
Not recommended in pediatric populations due to lack of safety data.
Patients should be informed about signs of overdose, including confusion and hallucinations.
Observe caution in elderly patients with comorbidities affecting drug clearance.
Do not crush, chew, or break extended-release tablets to maintain pharmacokinetic profile.

Contraindication

Known allergy to ranolazine or any components of the formulation.
Cirrhosis of the liver due to severely impaired metabolism and increased toxicity risk.
Concomitant use with strong CYP3A4 inhibitors such as clarithromycin, ketoconazole, itraconazole.
Concomitant use with strong CYP3A4 inducers including rifampin, phenobarbital, carbamazepine.
History or family history of congenital long QT syndrome.
Use in patients with documented QT interval prolongation or torsades de pointes.
Concomitant administration with drugs that significantly prolong QT interval increasing arrhythmia risk.
Known severe renal impairment without proper clinical monitoring or dosage adjustment.
Use during acute coronary syndromes or acute angina episodes.
Known hypersensitivity reactions to previously administered ranolazine or related compounds.
In combination with St. John's wort due to unpredictable induction of metabolism.
Patients unable to swallow extended-release tablets and without access to granule formulation.
Concomitant use with certain antiretrovirals like indinavir and ritonavir without adjustment.
Use with caution where compliance or monitoring is difficult or not feasible.
Pediatric patients due to lack of approved indications and safety data.

Drug Interactions

Clarithromycin and other macrolide antibiotics acting as strong CYP3A4 inhibitors increase ranolazine plasma levels, raising toxicity risk.
Itraconazole and ketoconazole, potent antifungal agents, strongly inhibit CYP3A4 metabolism of ranolazine.
Protease inhibitors for HIV/AIDS such as indinavir, lopinavir/ritonavir, nelfinavir, ritonavir, and saquinavir markedly increase ranolazine concentrations.
CYP3A4 inducers like rifampin, rifapentine, rifabutin, carbamazepine, phenobarbital, and phenytoin reduce ranolazine efficacy by lowering drug levels.
Co-administration with other QT-prolonging drugs increases the risk of torsades de pointes and ventricular arrhythmias.
Oral hypoglycemic agents may interact, requiring blood glucose monitoring.
Drugs used for organ transplant rejection prevention may alter ranolazine metabolism or vice versa.
Medications used in psychiatric disorders can have additive CNS effects or metabolic interactions.
Chemotherapy agents causing nausea and vomiting may require interaction assessment with ranolazine.
St. John's wort induces CYP3A4, decreasing ranolazine plasma concentration and reducing efficacy.
Careful monitoring when combined with other cardiovascular drugs, especially beta-blockers and calcium channel blockers, although direct pharmacokinetic interactions may be minimal.
Potential interactions with over-the-counter medications, vitamins, and herbal supplements necessitate full medication review.
Multiple drug-drug interactions underscore the importance of reporting all concomitant medications to prescribers and pharmacists.
Avoid grapefruit or grapefruit juice due to CYP3A4 inhibition leading to increased ranolazine blood levels.
Dose modification or avoidance may be necessary when combined with drugs affecting cardiac conduction.

Preparations Of The Drug

Ranexa (Ranolazine extended-release tablets) available in 500 mg and 1000 mg strengths.
Aspruzyo Sprinkle (Ranolazine extended-release oral granules) available in 500 mg and 1000 mg packets for mixing with soft food.
Extended-release formulation designed for twice-daily dosing.
Oral tablet prepared as a film-coated, sustained-release formulation to maintain therapeutic levels.
Granule formulation suitable for patients with swallowing difficulties or use via feeding tubes.
Storage recommended at room temperature, protected from moisture and heat.
Packaging designed to maintain integrity of extended-release properties.
Manufactured under strict quality control to ensure bioavailability and stability.
Dispensed with medication guide highlighting proper administration and safety precautions.
Available through prescription with specific dosing guidance from healthcare providers.
Not designed for immediate release; formulations are intended for chronic use only.
Packaging may include single-dose packets for granules to ensure dosing accuracy.
Proper labeling includes warnings about interactions and contraindications.
Patient instructions provided to avoid crushing or chewing tablets to prevent dose dumping.
Compatibility with soft foods like applesauce or yogurt explicitly stated for granule administration.