Alpha-1 Adrenergic Blockers, Also Called Alpha Blockers

Alpha blockers are a type of a larger class of medicines called adrenergic inhibitors. They are used to treat high blood pressure by widening, or dilating, blood vessels. Alpha-blockers are used alone or in combination with other blood pressure medicines, including diuretics.

Common Names of Alpha Blockers

The following table lists some of the common brand and generic names for alpha blockers.

brand generic
Cardura doxazocin mesylate
Hytrin terazosin HCl
Minipress prazosin HCl


How Alpha Blockers Work

Your brain produces chemicals called neurotransmitters. Neurotransmitters called catecholamines are normally released when you are under stress. These chemicals cause your heart to beat faster and with more force. They also cause your blood vessels to narrow. Both of these actions raise your blood pressure. Alpha blockers block catecholamines. The result is that your heart beats more slowly and with less force. Your blood vessels also relax and widen so that blood flows through them more easily. Both of these actions lower blood pressure. The actions also allow the heart to get more blood and oxygen.

Precautions and Possible Side Effects

Precautions to take when you are on alpha blockers:

  • Talk with your doctor if you experience faintness or dizziness. Blood pressure medicines can occasionally cause dizziness. This is most likely when you change position suddenly. But this may also be caused by other physical or medical problems that have nothing to do with your medicines.
  • Keep all your follow-up appointments with your doctor. Your doctor will check to see how your medicine is working and will adjust it if needed.

Possible side effects of alpha blockers:

  • dizziness or faintness
  • drowsiness
  • headache
  • slow heartbeat

Not everyone who takes alpha blockers will have these side effects. You should not be afraid to take your medicine because of the side effects listed. They are listed so that you can watch out for them and tell your doctor right away if you experience any of them.

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Possible Drug Interactions With Alpha Blockers

Before you take an alpha blocker, tell all of your doctors and your pharmacist about all the medicines you take. Include medicines you take for your blood pressure as well as for any other problem. Tell them about everything you take and how much you take each day, including all of the following:

  • prescription medicines
  • over-the-counter medicines
  • herbs
  • vitamin and mineral supplements

It's best to keep an updated list of these and bring a copy to give to your doctor. That way you can add to it whenever you take something new or delete the types you no longer take. Make a copy for each of your doctors so that they can keep it in your file. This complete list helps your doctor be better prepared to prescribe an alpha blocker that is the least likely to interact with your other treatments.

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