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Why is this medication prescribed?

Hydralazine is prescribed for the treatment of high blood pressure (hypertension) and certain heart conditions, such as congestive heart failure. It is classified as a vasodilator, which means it works by relaxing and widening the blood vessels, allowing blood to flow more easily.

When prescribed for hypertension, hydralazine is often used in combination with other medications to help lower blood pressure. It may be prescribed when other antihypertensive medications have not been effective or are contraindicated.

How should this medicine be used?

The dosage and usage instructions for hydralazine may vary depending on the individual and the specific condition being treated. It is important to follow the directions provided by your healthcare provider or the instructions on the medication label. Here are some general guidelines:

  • Hydralazine is typically taken orally, usually two to four times a day.
  • The medication may be taken with or without food, but it is advisable to take it consistently in the same manner.
  • The dosage will be determined by your healthcare provider based on your specific condition and response to treatment. It is important to follow the prescribed dosage and not to adjust it without consulting your doctor.
  • It is essential to take hydralazine regularly to maintain its effectiveness. If you miss a dose, take it as soon as you remember. However, if it is close to the time for your next dose, skip the missed dose and resume your regular dosing schedule. Do not take a double dose to make up for a missed one.
  • It may take several weeks of consistent use to see the full benefits of hydralazine. Do not stop taking the medication abruptly without consulting your healthcare provider, as it may cause a sudden increase in blood pressure.

Other uses for this medicine

Hydralazine is primarily used as a medication to treat high blood pressure. However, there are a few other potential uses for hydralazine, although they are less common and typically considered off-label:

  • Heart failure: Hydralazine may be used in combination with other medications to manage heart failure symptoms in certain cases. It helps relax and widen blood vessels, reducing the workload on the heart.
  • Hypertensive crisis: Hydralazine can be administered intravenously in a hospital setting to rapidly lower blood pressure during a hypertensive crisis, a severe and potentially dangerous increase in blood pressure.

It’s important to note that these uses of hydralazine should be prescribed and supervised by a healthcare professional, as they may have specific indications and dosing guidelines.

What special precautions should I follow?

Regarding precautions, it is crucial to follow your healthcare provider’s instructions and take the following precautions while using hydralazine:

  • Allergies: Inform your doctor if you have any known allergies to hydralazine or any other medications, as hydralazine may contain inactive ingredients that can cause allergic reactions or other problems.
  • Medical conditions: Discuss your medical history with your doctor, especially if you have a history of heart disease, kidney disease, systemic lupus erythematosus (SLE), or any blood vessel-related disorders, as these conditions may affect the suitability and dosing of hydralazine.
  • Pregnancy and breastfeeding: Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding. The use of hydralazine during pregnancy or breastfeeding should be discussed with your doctor to weigh the potential benefits against the risks.
  • Medications and supplements: Inform your doctor about all the medications, supplements, and herbal products you are currently taking, as certain drugs may interact with hydralazine, leading to adverse effects or reduced efficacy. Examples include other blood pressure medications, medications for erectile dysfunction, and medications that affect liver enzymes (such as cimetidine).
  • Blood pressure monitoring: Regularly monitor your blood pressure as instructed by your doctor to ensure that hydralazine is effectively managing your condition. Report any significant changes or concerns to your healthcare provider.

What special dietary instructions should I follow?

There are no specific dietary instructions associated with taking hydralazine. However, it is generally recommended to maintain a healthy and balanced diet while taking any medication, including hydralazine. A healthy diet typically consists of a variety of fruits, vegetables, whole grains, lean proteins, and limited amounts of saturated fats, sodium, and added sugars. It’s always a good idea to discuss any specific dietary concerns or restrictions with your healthcare provider or a registered dietitian.

What should I do if I forget a dose?

If you forget to take a dose of hydralazine, take it as soon as you remember, unless it is close to the time for your next scheduled dose. In that case, skip the missed dose and continue with your regular dosing schedule. It is important not to double up on doses to make up for a missed one. If you have any concerns or questions about missed doses or your dosing schedule, it is advisable to consult your healthcare provider for guidance.

What side effects can this medication cause?

Hydralazine is a medication primarily used to treat high blood pressure (hypertension). While it can be effective in managing hypertension, it may also cause certain side effects. Some of the common side effects of hydralazine include:

  • Headache: One of the most frequently reported side effects of hydralazine is headaches. These headaches can range from mild to severe.
  • Dizziness and lightheadedness: Hydralazine can cause a drop in blood pressure, leading to dizziness and lightheadedness, especially when standing up quickly. It is important to rise slowly from a sitting or lying position to minimize this effect.
  • Flushing: Hydralazine may cause flushing or a sensation of warmth and redness of the skin, particularly on the face, neck, and chest. This reaction is due to the dilation of blood vessels.
  • Rapid heartbeat (tachycardia): Hydralazine can increase heart rate, causing palpitations or a rapid heartbeat. If this side effect becomes bothersome, it is advisable to consult a healthcare professional.
  • Nausea and vomiting: Some individuals may experience gastrointestinal disturbances such as nausea and vomiting while taking hydralazine. Taking the medication with food may help alleviate these symptoms.
  • Fluid retention: In some cases, hydralazine may lead to fluid retention, causing swelling in the legs, ankles, or feet. It is essential to monitor any sudden or significant weight gain and promptly inform a healthcare provider if it occurs.
  • Joint pain: Hydralazine has been associated with joint pain or aches in certain individuals. If this side effect is persistent or severe, medical advice should be sought.
  • Blood disorders: Rarely, hydralazine can cause blood disorders such as agranulocytosis (a severe reduction in white blood cells), which may increase the risk of infection. Symptoms of infection, such as fever, sore throat, or mouth sores, should be promptly reported to a healthcare professional.
  • Other side effects: Hydralazine can occasionally cause additional adverse effects, including a lupus-like syndrome, which may involve symptoms such as rash, fever, joint pain, and muscle aches. It may also cause a decrease in red or white blood cell counts.

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

When it comes to storage and disposal of hydralazine, here are some important considerations:


  • Follow the storage instructions provided by your healthcare provider or pharmacist.
  • Typically, hydralazine is stored at room temperature, away from direct sunlight and moisture.
  • Keep the medication out of reach of children and pets to prevent accidental ingestion.


  • Do not dispose of hydralazine in household trash or flush it down the toilet unless instructed to do so.
  • Properly dispose of unused or expired hydralazine by returning it to a pharmacy or using a drug take-back program in your community.
  • Consult your pharmacist or local waste disposal facility for specific guidelines on medication disposal.

In case of emergency/overdose

  • In case of an emergency or suspected overdose, call emergency services or your local poison control center immediately.
  • Symptoms of an overdose may include severe dizziness, fainting, rapid heartbeat, difficulty breathing, or seizures.
  • If possible, provide emergency responders or healthcare professionals with information about the medication and the amount ingested.

What other information should I know?

  • Inform your healthcare provider about any known allergies or sensitivities you have before taking hydralazine.
  • Notify your doctor of any other medications, supplements, or herbal products you are taking, as they can interact with hydralazine.
  • Hydralazine may cause drowsiness or dizziness, so avoid activities that require alertness until you know how the medication affects you.
  • It is important to take hydralazine as prescribed and not to adjust the dosage without consulting your healthcare provider.
  • Regularly monitor your blood pressure and follow up with your healthcare provider to ensure the medication is effectively managing your condition.

Please note that the information provided here is for general knowledge and should not replace the specific instructions and advice given by your healthcare provider.

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