Verapamil/diltiazem (risk of severe bradycardia/heart block), amiodarone/other antiarrhythmics, digoxin, clonidine (rebound risk on withdrawal), insulin/oral antidiabetics (masked hypoglycaemia), NSAIDs (may reduce antihypertensive effect), other antihypertensives, alcohol (may increase dizziness), CYP inhibitors like cimetidine/fluoxetine (may increase propranolol levels), bronchodilators like salbutamol (reduced effect)