Selected Beta-Blockers/Selected Alpha-Blockers Interactions

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Beta-blockers may increase the chance that you will have a sudden decrease in your blood pressure when starting your alpha-blocker.

What might happen:

You may experience a sudden decrease in your blood pressure when starting an alpha-blocker, if you are already taking a beta-blocker. This problem may be worsened if you are also taking a water pill (e.g. a diuretic) or are on a low salt diet.

What you should do about this interaction:

Make sure your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. Your doctor may want to change your medicine.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

  • 1.Elliott HL, McLean K, Sumner DJ, Meredith PA, Reid JL. Immediate cardiovascular responses to oral prazosin--effects of concurrent beta-blockers. Clin Pharmacol Ther 1981 Mar;29(3):303-9.
  • 2.Graham RM, Thornell IR, Gain JM, Bagnoli C, Oates HF, Stokes GS. Prazosin: the first-dose phenomenon. Br Med J 1976 Nov 27;2(6047):1293-4.
  • 3.Rubin P, Jackson G, Blaschke T. Studies on the clinical pharmacology of prazosin. II: The influence of indomethacin and of propranolol on the action and disposition of prazosin. Br J Clin Pharmacol 1980 Jul; 10(1):33-9.
  • 4.Seideman P, Grahnen A, Haglund K, Lindstrom B, Von Bahr C. Prazosin first dose phenomenon during combined treatment with a beta- adrenoceptor blocker in hypertensive patients. Br J Clin Pharmacol 1982 Jun; 13(6):865-70.
  • 5.Minipress (prazosin hydrochloride) US prescribing information. Pfizer Inc. February, 2015.
  • 6.Hytrin (terazosin hydrochloride) US prescribing information. Abbott Laboratories July, 2009.
  • 7.Cardura (doxazosin hydrochloride) US prescribing information. Pfizer, Inc. June, 2016.
  • 8.Uroxatral (alfuzosin hydrochloride) US prescribing information. Sanofi-Synthelabo, Inc. May, 2013.

Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, except as may be authorized by the applicable terms of use.

CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.