Ranolazine was FDA approved in 2006 for the treatment of chronic angina.[1][2][3]

Angina is characterized by chest discomfort that occurs due to ischemia. Stable angina is treated to reduce the symptoms and occurrence of ischemia and to prevent myocardial infarction and mortality. Standard therapy includes aspirin, P2Y12 inhibitors, angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers, statins, beta-blockers, calcium-channel blockers, and nitrates. Ranolazine may be used in combination with these agents to treat angina.

Off-label uses include the treatment of some arrhythmias, such as ventricular tachycardia. However, there is little data to support this use.

The mechanism of ranolazine's anti-anginal and anti-ischemic effects is not well understood. It inhibits late sodium currents in cardiac cells which decreases intracellular calcium overload and improves coronary blood flow. It does not significantly reduce blood pressure or heart rate. The Monotherapy Assessment of Ranolazine in Stable Angina (MARISA) trial randomized 191 patients with activity-limiting angina to 500 mg, 1000 mg, or 1500 mg twice daily or placebo for one week. Ranolazine significantly increased exercise duration in comparison to placebo and had negligible effects on heart rate and blood pressure. [4][5][6][4]

Ranolazine also inhibits fatty acid oxidation. This enhances glucose oxidation, reduces the production of lactic acid and improves heart function.

Ranolazine is available as 500-mg and 1000-mg extended-release tablets. The tablets are film-coated and not scored; they should not be crushed, broken or chewed. Dosing should begin at 500 mg twice daily and titrated to 1000 mg twice daily as tolerated. The maximum recommended dose is 1000 mg twice a day. Food does not alter the rate of absorption or the area under plasma concentration-time curve (AUC). Ranolazine can, therefore, be administered with or without meals. Peak plasma concentrations are reached between 2 to 5 hours, the half-life is 7 hours, and steady state is achieved within three days.

Dose adjustment is required when ranolazine is taken with moderate CYP3A inhibitors like verapamil, diltiazem, and erythromycin. The dose should not exceed 500 mg twice a day. Dosing should be titrated to clinical response in patients on concomitant P-glycoprotein inhibitors, for example, cyclosporine because they may also increase ranolazine plasma concentrations.

Clinical Evidence

The Combination Assessment of Ranolazine in Stable Angina (CARISA) trial was a multinational, randomized, double-blind, placebo-controlled trial of patients with symptomatic chronic angina despite taking standard doses of diltiazem, atenolol or amlodipine. Patients were randomly assigned to receive placebo or 750 mg or 1000 mg of ranolazine twice a day. Outcome measures included a change in exercise time, time to onset of symptoms, time to onset of ischemia, need for nitroglycerin and number of angina attacks. Exercise duration, time to angina symptoms and time to ischemia increased more from baseline in both ranolazine groups compared to the placebo group. Exercise tolerance increased with ranolazine dose and plasma concentration. These changes were independent of heart rate, blood pressure or background antianginal therapy. Angina attacks and nitroglycerin use were reduced by about seven days in the ranolazine group compared to placebo.

In the Efficacy of Ranolazine in Chronic Angina (ERICA) trial, ranolazine reduced the frequency of anginal symptoms and nitroglycerin use compared to placebo in patients with coronary artery disease who still had symptoms despite therapy with amlodipine 10 mg a day.[7][8][9][10]

In clinical trials, approximately 6% of patients discontinued treatment because of an adverse event versus 3% in the placebo groups. The most common adverse events that led to discontinuation were dizziness, headaches, nausea, debility, and constipation. Other side effects included the following: syncope, confusion,  tinnitus, vertigo, blurred vision, dyspnea, hematuria, bradycardia, palpitations, hypotension, orthostatic hypotension, thrombocytopenia, leukopenia, abdominal pain, dry mouth, vomiting, anorexia, dyspepsia, peripheral edema, angioedema, renal failure, eosinophilia, paresthesia, tremor, pulmonary fibrosis, and excessive sweating.

Postmarketing adverse effects include hallucinations, tremor, paresthesia, abnormal coordination, dysuria, and rash. Reported neurologic effects are usually dose-dependent and resolve upon discontinuation.

Ranolazine is metabolized in the liver mainly by CYP3A4  and CYP2D6 enzymes. It is also a substrate of P-glycoprotein. Strong CYP3A4 inhibitors like ketoconazole, clarithromycin, and ritonavir increase ranolazine levels, and concomitant use is contraindicated. Moderate CYP3A4 inhibitors such as diltiazem,  fluconazole, erythromycin, and verapamil increase ranolazine levels. When used together, ranolazine dose should not exceed 500 mg twice a day, and close monitoring is needed. CY3A4 inducers such as rifampin, carbamazepine, phenytoin, and St. John’s Wort decrease ranolazine plasma levels and concomitant use is not recommended. There are no recommended dose adjustments for patients with hepatic impairment, but usage is contraindicated in patients with cirrhosis of the liver.

Ranolazine inhibits the tubular secretion of creatinine. This does not affect glomerular filtration rate. However acute renal failure, in patients with marked severe impairment (creatinine clearance [CrCl] less than 30 ml per minute) has been reported. Discontinue therapy if renal failure occurs and do not initiate therapy in patients with a CrCl less than 30 ml per minute. Use in dialysis patients is contraindicated.

Ranolazine may prolong QT via inhibition of potassium current (IKr). Torsades de pointes was not reported as a side effect in clinical trials, but the risk may increase in patients who are also taking other QT-prolonging medications. Hepatic impairment may also lead to increased plasma concentrations, and hence, prolonged QTc interval. Caution is advised in patients with a family history of long QT syndrome and patients with known prolonged QT interval.

Co-administration of ranolazine and metformin, each at a dose of 1000 mg twice a day, resulted in increased plasma concentrations of metformin. Patients on ranolazine 1000 mg twice a day should not exceed a total daily dose of 1700 mg metformin, and their blood glucose should be followed closely.

There is a lack of data on the use of ranolazine in pregnant women, during lactation and in the pediatric population. Close monitoring is required in patients 75 years of age or older as they are more likely to experience adverse effects with ranolazine.