Propranolol’s effects can be altered by several other medications. Always inform your doctor of all medications you are taking, including over-the-counter drugs, herbal supplements, and vitamins. This includes prescription drugs, even if you only take them occasionally.
Specific Medication Interactions
Combining propranolol with certain medications can increase the risk of side effects or reduce the effectiveness of either drug. For example, using propranolol concurrently with calcium channel blockers (like verapamil or diltiazem) might significantly lower your heart rate and blood pressure. Similarly, combining it with insulin or other oral hypoglycemic agents may increase the risk of hypoglycemia (low blood sugar). Combining with MAO inhibitors can also cause dangerous interactions, potentially leading to severe hypertension. Non-steroidal anti-inflammatory drugs (NSAIDs) can reduce propranolol’s effectiveness.
Specific attention should be paid to interactions with: warfarin (increased bleeding risk), clonidine (increased blood pressure lowering effect), and caffeine (reduced blood pressure lowering effect). Your doctor will likely need to adjust dosages if you’re using propranolol alongside these medications.
