Current angina guidelines suggest that beta blockers and/or calcium channel blockers are the mainstays of therapy for symptom relief. But what if these agents are not enough or not tolerated? Now, there is an additional option to consider called Corzyna.
Corzyna, otherwise known as ranolazine, is an add-on medication for the treatment of anginal symptoms who have not adequately responded to beta blockers or calcium channel blockers. Ranolazine works by blocking the late cardiac sodium channel, resulting in QT prolongation. The connection between this mechanism and improved anginal symptoms is not clear. However, it is important to know that ranolazine does not affect blood pressure or heart rate (which is a limitation of beta blockers and calcium channel blockers).
The dose starts at 500 mg twice daily, which can be increased to 1000 mg twice daily. Note, these are extended release tablets which should not be cut or crushed.
The most common adverse effects of ranolazine include dizziness, headache, nausea and constipation.
Ranolazine has many drug interactions. Due to its QT prolonging action, it is contraindicated with other antiarrhythmics (class 1a and III). Caution is advised for other QT prolonging drugs. Ranolazine is also metabolized by CYP3A4 and p-gp, so strong inhibitors such as clarithromycin and cyclosporine should be avoided. In addition, patients taking diltiazem or verapamil should receive a maximum of 500 mg twice daily due to the moderate CYP3A4 inhibition by these calcium channel blockers.
Ranolazine itself is a moderate CYP2D6 and weak CYP3A4 inhibitor, so caution should be used with other drugs metabolized through this pathway.