Drug Interactions With Propranolol
The following sections explain in detail the potentially negative interactions that can occur when propranolol is combined with any of the drugs listed above.
Alcohol may increase the level of propranolol in the blood, increasing the risk of propranolol side effects. Talk with your healthcare provider about whether or not you should drink alcohol (and how much you can drink) while taking propranolol.
Combining propranolol with an alpha blocker can increase the risk of dangerously low blood pressure (hypotension). Check with your healthcare provider before combining such medications.
Calcium Channel Blockers
Combining propranolol with certain calcium channel blockers may cause a dangerously low blood pressure and (for verapamil or diltiazem), a slow heart rate (bradycardia) and heart failure. You may need to be monitored very closely if you take these medications together. In some cases, it is not recommended to combine propranolol with a calcium channel blocker.
Certain Arrhythmia Medications
Combining propranolol with certain arrhythmia medications may cause a dangerously slow heart rate (bradycardia) or very low blood pressure. You may need to be monitored very closely if you take these medications together. In some cases, it is not recommended to combine propranolol with an arrhythmia medication.
If you take both clonidine and propranolol, stopping clonidine (without stopping propranolol) could increase the risk of dangerously high blood pressure, strokes, and other serious problems. It is advised to stop taking propranolol several days before you gradually reduce the dose of clonidine. Do not attempt this without the approval and supervision of your healthcare provider. If you are switching from clonidine to propranolol, it is advised to wait several days after stopping clonidine before starting propranolol.