Propranolol × Verapamil

Verapamil and propranolol both slow the heart rate and conduction through the atrioventricular (AV) node and reduce myocardial contractility; taken together, these effects add up (verapamil and propranolol SmPCs). With verapamil and beta-blockers, marked bradycardia, AV block up to complete heart block, heart failure and cardiovascular collapse have been reported (verapamil and propranolol labels of the US Food and Drug Administration, FDA). The risk is higher with impaired ventricular function and with sinoatrial or AV conduction disorders (propranolol SmPC).

Slow pulse, dizziness, weakness, fainting, a sharp fall in blood pressure. Shortness of breath and swelling if heart failure develops. On the electrocardiogram (ECG): high-grade atrioventricular block (verapamil and propranolol SmPCs).

Avoid the combination, especially in decompensated heart failure (propranolol SmPC). Avoid verapamil in patients on a beta-blocker who have any degree of ventricular dysfunction (verapamil label of the US Food and Drug Administration, FDA). Intravenous verapamil is contraindicated in patients receiving an intravenous beta-blocker, and the intravenous forms of the two drugs are not given within a few hours of each other (FDA label for verapamil injection). If the patient is taking one of the drugs, stop it 48 hours before giving the other intravenously and 7 days before starting the other by mouth (propranolol SmPC). If the combination is still used for hypertension, use it only with caution and close monitoring (verapamil FDA label); if second- or third-degree atrioventricular block develops, withhold further verapamil doses (verapamil SmPC).