Hydralazine: Uses, Side Effects

Hydralazine is a vasodilator that works by relaxing the muscles in your blood vessels to help them dilate (widen). This lowers blood pressure and allows blood to flow more easily through your veins and arteries.

Hydralazine is used to treat high blood pressure (hypertension).

Hydralazine may also be used for purposes not listed in this medication guide.


Before taking this medicine

You should not use hydralazine if you are allergic to it, or if you have:

  • coronary artery disease; or
  • rheumatic heart disease affecting the mitral valve.

To make sure hydralazine is safe for you, tell your doctor if you have ever had:

  • kidney disease;
  • systemic lupus erythematosus;
  • angina (chest pain); or
  • a stroke.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Hydralazine can pass into breast milk, but effects on the nursing baby are not known. Tell your doctor if you are breast-feeding.

Hydralazine is not approved for use by anyone younger than 18 years old.


Side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • chest pain or pressure, pain spreading to your jaw or shoulder;
  • fast or pounding heartbeats;
  • a light-headed feeling, like you might pass out;
  • numbness, tingling, or burning pain in your hands or feet;
  • painful or difficult urination;
  • little or no urination; or
  • lupus-like syndrome–joint pain or swelling with fever, swollen glands, muscle aches, chest pain, vomiting, unusual thoughts or behavior, and patchy skin color.

Common side effects may include:

  • chest pain, fast heart rate;
  • headache; or
  • nausea, vomiting, diarrhea, loss of appetite.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.


What other drugs will affect hydralazine?

Tell your doctor about all your current medicines and any you start or stop using, especially:

  • diazoxide (an injectable blood pressure medication); or
  • an MAO inhibitor–isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.

This list is not complete. Other drugs may interact with hydralazine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.


Keyword: hydralazine.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.