URL of this page: https://www.nlm.nih.gov/medlineplus/druginfo/meds/a682246.html


pronounced as (hye dral' a zeen)

Why is this medication prescribed?

Hydralazine is used to treat high blood pressure. Hydralazine is in a class of medications called vasodilators. It works by relaxing the blood vessels so that blood can flow more easily through the body.

High blood pressure is a common condition and when not treated, can cause damage to the brain, heart, blood vessels, kidneys and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressure. These changes include eating a diet that is low in fat and salt, maintaining a healthy weight, exercising at least 30 minutes most days, not smoking, and using alcohol in moderation.

How should this medicine be used?

Hydralazine comes as a tablet to take by mouth. It usually is taken two to four a day. Take hydralazine at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take hydralazine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Hydralazine controls high blood pressure but does not cure it. Continue to take hydralazine even if you feel well. Do not stop taking hydralazine without talking to your doctor.

Other uses for this medicine

Hydralazine is also used after heart valve replacement and in the treatment of heart failure. Talk to your doctor about the possible risks of using this medication for your condition.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?

Before taking hydralazine,

  • tell your doctor and pharmacist if you are allergic to hydralazine, aspirin, tartrazine (a yellow dye in some processed foods and medications), any other medications, or any of the ingredients in hydralazine tablets. Ask your pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Be sure to mention any of the following: indomethacin (Indocin, Tivorbex), metoprolol (Lopressor, Toprol-XL, in Dutoprol), and propranolol (Inderal LA, Innopran XL, in Inderide).
  • tell your doctor if you have ever had a heart attack, or have coronary artery disease, rheumatic heart disease, or heart, kidney or liver disease.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking hydralazine, call your doctor.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking hydralazine.
  • ask your doctor about the safe use of alcohol while you are taking hydralazine. Alcohol can make the side effects from hydralazine worse.

What special dietary instructions should I follow?

Take hydralazine with meals or a snack.

Your doctor may prescribe a low-salt or low-sodium diet. Follow these directions carefully.

What should I do if I forget a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What side effects can this medication cause?

Hydralazine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • flushing
  • headache
  • upset stomach
  • vomiting
  • loss of appetite
  • diarrhea
  • constipation
  • eye tearing
  • stuffy nose
  • rash

Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:

  • fainting
  • joint or muscle pain
  • fever
  • rapid heartbeat
  • chest pain
  • swollen ankles or feet
  • numbing or tingling in hands or feet

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/Safety/MedWatch] or by phone [1-800-332-1088].

What should I know about storage and disposal of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

In case of emergency/overdose

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

What other information should I know?

Keep all appointments with your doctor and the laboratory. Your blood pressure should be checked regularly to determine your response to hydralazine.

Your doctor may ask you to check your blood pressure daily. Ask your doctor or pharmacist to teach you how.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

Brand names

  • Apresoline®
  • Dralzine®

Brand names of combination products

  • Apresazide® (containing Hydralazine, Hydrochlorothiazide)
  • Apresoline-Esidrix® (containing Hydralazine, Hydrochlorothiazide)
  • BiDil® (containing Hydralazine, Isosorbide Dinitrate)
  • Dralserp® (containing Hydralazine, Reserpine)
  • Hydra-Zide® (containing Hydralazine, Hydrochlorothiazide)
  • Hydrap-ES® (containing Hydralazine, Hydrochlorothiazide, Reserpine)
  • Marpres® (containing Hydralazine, Hydrochlorothiazide, Reserpine)
  • Ser-Ap-Es® (containing Hydralazine, Hydrochlorothiazide, Reserpine)
  • Serathide® (containing Hydralazine, Hydrochlorothiazide, Reserpine)
  • Serpazide® (containing Hydralazine, Hydrochlorothiazide, Reserpine)
  • Serpex® (containing Hydralazine, Hydrochlorothiazide, Reserpine)
  • Unipres® (containing Hydralazine, Hydrochlorothiazide, Reserpine)

This branded product is no longer on the market. Generic alternatives may be available.

Last Revised - 02/15/2015