Ranolazine, sold under the trade name Ranexa by Gilead Sciences (who acquired the developer, CV Therapeutics in 2009), is an antianginal medication. In India it is sold under the name "Ranozex". On January 31, 2006, ranolazine was approved for use in the United States by the FDA for the treatment of chronic angina pectoris.

Ranolazine is believed to have its effects via altering the trans-cellular late sodium current. It is by altering the intracellular sodium level that ranolazine affects the sodium-dependent calcium channels during myocardial ischemia in rabbits. Thus, ranolazine indirectly prevents the calcium overload that causes cardiac ischemia in rats.

Ranolazine is indicated for the treatment of Chronic angina. Ranolazine may be used with beta-blockers,nitrates, calcium channel blockers, anti-platelet, therapy, lipid-lowering therapy, ACE inhibitors, and angiotensin receptor blockers. It has been shown to decrease angina episodes in individuals with coronary artery disease on maximal doses of amlodipine. In addition, it has been shown to both decrease angina episodes and increase exercise tolerance in individuals taking concomitant atenolol, amlodipine, or diltiazem.

Unlike other antianginal medications such as nitrates and beta blockers, ranolazine does not significantly alter either the heart rate or blood pressure. For this reason, it is of particular use in individuals with angina that is refractory to maximal tolerated doses of other anti-anginal medications.

While it would seem from the mechanism of action that ranolazine may be of benefit in individuals with non-ST-elevation acute coronary syndromes and acute myocardial infarction (heart attack), the recently completed Merlin/TIMI-36 trial showed no benefit in this population.

Ranolazine is advised by the FDA as being known to increase the QT interval on the electrocardiogram. While the mean increase in the QTc is approximately 6 msec, about 5 percent of individuals may have QTc prolongations of 15 msec or longer.

Extended Qt intervals are extremely dangerous and result in sudden cardiac death SCD. "February 3, 2006 -- A recent analysis of the prospective, population-based Rotterdam Study found that prolongation of the heart-rate corrected QT (QTc) interval increased the risk of sudden cardiac death (SCD) in adult patients by 60%, independent of other known risk factors. "

Because of this, caution should be used when ranolazine is used in combination with other medications that increase the QT interval. In addition, because the effect of ranolazine on the QT interval is increased in the setting of liver dysfunction, it is contraindicated in the setting of mild, moderate, or severe liver disease.

Ranolazine is metabolized in the liver, particularly by one of the cytochrome CYP3A enzymes, a member of the cytochrome P450 system.

While ranolazine is not significantly metabolized by cytochrome CYP2D6, it does inhibit this enzyme. Because of this, the doses of medications metabolized by cytochrome CYP2D6 may need to be reduced to prevent toxicity.