Ranolazine: add-on tablet for stable angina

Ranolazine is indicated as add-on therapy for symptomatic treatment of stable angina in adults whose symptoms are inadequately controlled by first-line antianginal medicines. The key word is add-on: it is used together with, not instead of, other angina treatment.

Stable angina is chest discomfort that comes on predictably with exertion. Treatment aims to prevent attacks, while a spray or tablet of GTN relieves them quickly. Ranolazine belongs to the first group and does not replace your emergency spray.

The SmPC describes starting at 375mg twice daily, increasing to 500mg twice daily after 2 to 4 weeks depending on response and tolerability, up to a maximum recommended dose of 750mg twice daily. The tablets are prolonged-release and must be swallowed whole, not crushed, broken or chewed.

Because dose changes are guided by how you tolerate the medicine, report dizziness, nausea or constipation early.

The SmPC lists severe kidney impairment (creatinine clearance below 30ml/min), moderate or severe liver impairment, potent CYP3A4 inhibitors such as ketoconazole, itraconazole and HIV protease inhibitors, and class Ia or III anti-arrhythmics other than amiodarone as contraindications.

Make sure your prescriber knows about all your medicines and your kidney and liver function.

Ranolazine causes a small dose-related lengthening of the QT interval on the ECG, in the range of a few milliseconds at usual doses. This matters mainly for people with a history of long QT syndrome or those taking other medicines that lengthen it.

If you have fainting, dizziness with palpitations or an unusual heartbeat, seek medical help. Your clinician may check an ECG, especially if doses rise or other medicines are added.

Moderate CYP3A4 inhibitors such as diltiazem and erythromycin, and P-glycoprotein inhibitors such as verapamil, require careful dose titration. Simvastatin dosing must be limited to 20mg daily because of the risk of muscle damage (rhabdomyolysis).

Check every new medicine with a pharmacist, including over-the-counter and herbal products.

Common effects are dizziness and headache, and gastrointestinal effects such as nausea, vomiting and constipation. They occur more often in older people, people with low body weight and those with kidney impairment.

Report suspected side effects through the MHRA Yellow Card scheme. Do not stop abruptly without asking your cardiologist, and keep a GTN spray for attacks.

Because ranolazine is an add-on, the useful question at a review is whether your symptoms have improved on the combination, not on ranolazine alone. Keep a short diary of attacks, how much GTN you needed and what you were doing, so that the prescriber can judge whether to move up through the doses described in the SmPC.

Tell the prescriber about constipation, dizziness or nausea early, since these are the commonly reported effects and may be easier to manage at lower doses. Mention if you are given a new antibiotic, an antifungal, a statin or a heart medicine, because several of these can interact with ranolazine. If you have an ECG for any reason, let the staff know you take it.