Uses

What is hydralazine used for?

Hydralazine is commonly used for high blood pressure (hypertension). 

Hydralazine may also be used for other conditions as determined by your healthcare provider.

How does hydralazine work (mechanism of action)?

Hydralazine helps to relax blood vessels in your body. This allows blood to flow more easily through the vessels, which lowers blood pressure. Lowering blood pressure is important to prevent problems with your heart or kidneys and decrease the risk of stroke or heart attack. 

How is hydralazine supplied (dosage forms)?

Hydralazine is available in the following dosage forms that are taken by mouth.

  • 10 mg oral tablets
  • 25 mg oral tablets
  • 50 mg oral tablets
  • 100 mg tablets

Hydralazine is also available in injectable forms.

How should I store hydralazine?

Hydralazine should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C), for shorter periods of time, such as when transporting it. Store in a cool, dry place. Keep tightly closed. Protect from light.

Side Effects

What are the most common side effects of hydralazine?

The most common side effects of hydralazine are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • Headache
  • Decreased appetite
  • Nausea and vomiting
  • Diarrhea
  • Pounding or fast heartbeat
  • Chest pain or discomfort (see below)

There may be other side effects of hydralazine that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of hydralazine?

While less common, the most serious side effects of hydralazine are described below, along with what to do if they happen.

Lupus-like Symptoms. Hydralazine can cause symptoms that look like a condition called lupus. Call your healthcare provider right away if you develop any of the following symptoms. 

  • Rash
  • Joint pain
  • Fever
  • Weakness or unusual tiredness
  • Swollen glands
  • Reduced need to pee
  • Pink, red, or brown pee 
  • Swelling 

Chest Pain. Hydralazine can cause chest pain, which can be a symptom of a heart attack. The risk of chest pain is increased in people with existing heart disease. Do not take hydralazine if you have had a recent heart attack without talking to your healthcare provider. Get emergency help if you have any of the following symptoms of a heart attack.

  • Chest pain or pressure
  • Fast or abnormal heartbeat
  • Trouble breathing
  • Pain in your back, jaw, throat, or arm
  • Sweating, upset stomach, vomiting, or dizziness

Blood Disorders. Hydralazine can cause blood disorders such as agranulocytosis, anemia, and low white blood cell count (leukopenia). Call your healthcare provider right away if you have any of the following symptoms of blood disorders.

  • Fever
  • Shortness of breath
  • Pale or yellowish skin
  • Easy bruising or bleeding
  • Frequent infection
  • Unusual weakness or tiredness
  • Dizziness, lightheadedness, or feeling like you are about to pass out
  • Headache
  • Fast or abnormal heartbeat

Nerve Problems. Nerves are the fibers that carry sensations from your body to the brain. Damage to these nerves, called peripheral neuropathy, can happen in people who are taking hydralazine. Stop taking hydralazine and call your healthcare provider if you develop pain, burning, tingling, numbness, or weakness in your arms, hands, legs, or feet.

Warnings & Precautions

Who should not use hydralazine?

Allergies to Ingredients. People who are allergic to any of the following should not use hydralazine.

  • Hydralazine
  • Apresoline
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific hydralazine products they stock.

Heart Disease. Hydralazine should not be used if you have coronary artery disease (CAD), which is a common type of heart disease. In CAD, the blood vessels (arteries) that supply blood to the heart muscle are blocked or narrowed. Hydralazine lowers blood pressure by relaxing your blood vessels. Relaxed blood vessels cause the heart to work harder, which can lead to a heart attack. 

Mitral Valvular Rheumatic Heart Disease. Hydralazine should not be used if you have damage to the mitral valve in your heart from rheumatic fever. When hydralazine relaxes the blood vessels, more blood flows to the heart, which can add strain to the mitral valve and make the heart work harder. 

What should I know about hydralazine before using it?

Do not take hydralazine unless it has been prescribed to you by a healthcare provider. Take it as prescribed.

Do not share hydralazine with other people, even if they have the same condition as you. It may harm them.

Keep hydralazine out of the reach of children.

Hydralazine can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how hydralazine affects you.

What should I tell my healthcare provider before using hydralazine?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if hydralazine is right for you.

Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

Heart disease, like coronary artery disease or previous heart attack

  • Kidney disease
  • Stroke
  • Rheumatic fever

Other Medicines and Supplements. Hydralazine may interact with other medicines and supplements. Before using hydralazine, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section below for more details.

Pregnancy. It is not known if or how hydralazine could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. Your healthcare provider will advise you if you should take hydralazine while you are pregnant or trying to get pregnant.

Breastfeeding. Hydralazine passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed. Your healthcare provider will advise you if you should take hydralazine while you are breastfeeding.

Interactions

Does hydralazine interact with foods or drinks?

There are no known interactions between hydralazine and foods or nonalcoholic drinks.

It is unknown if drinking alcohol will affect hydralazine. The risk of dizziness may be increased if you drink alcohol while taking hydralazine. 

Does hydralazine interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are taking any monoamine oxidase inhibitor (MAOI), which is a medicine usually used for depression or Parkinson’s Disease. 

Does Hydralazine HCL interact with other drugs you are taking?
Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much hydralazine?

If you or someone else has taken too much hydralazine, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of hydralazine?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses. 

Drug Survey

Are you currently using Hydralazine?

This survey is being conducted by the WebMD marketing sciences department.