Medically reviewed by Jessica Swirble, PharmD
Last updated on April 17, 2025
Drug Information | Side Effects | Use & Dosage | Request an Online Prescription
Hydralazine is a vasodilator used primarily to treat high blood pressure. It works by relaxing the muscles in the walls of blood vessels, helping them widen and lowering blood pressure.
Hydralazine is primarily used to treat conditions such as:
It may also be used in conjunction with other medications in the treatment of certain types of heart failure, although it is not FDA-approved for this purpose.
Hydralazine works by relaxing the smooth muscles in the walls of arteries, allowing them to widen. This decrease in the resistance that blood encounters as it flows through the vessels leads to a reduction in blood pressure.
Hydralazine can be taken in different forms, depending on the specific needs:
The dosage and duration of treatment depend on the condition being treated, its severity, and your response to the medication.
Follow your healthcare provider's instructions regarding dosage and schedule. Do not exceed the prescribed dose or duration of treatment without consulting your provider.
The effectiveness of hydralazine and the time it takes to notice improvement can vary among individuals. Blood pressure reduction can generally be observed within hours of taking the medication, but it may take several weeks to achieve desired blood pressure control.
Continue taking hydralazine as prescribed even if you start feeling better. Do not abruptly stop the medication, as it may lead to a rapid increase in blood pressure.
While hydralazine is primarily used for managing hypertension, healthcare providers may sometimes prescribe it off-label for conditions such as:
Discuss any alternative uses of hydralazine with your healthcare provider.
Hydralazine is available in the following dosage forms:
Generic versions of hydralazine are available, providing cost-effective treatment options.
Hydralazine is a prescription medication. You will need a valid prescription from a licensed healthcare provider to obtain this medication.
The use of hydralazine can lead to various side effects in some individuals.
Common mild side effects of hydralazine use include:
More severe side effects of hydralazine use can include:
If you experience any severe or concerning side effects while taking hydralazine, contact your healthcare provider right away.
Tell your healthcare provider about any existing medical conditions, allergies, or other medications you are taking before starting treatment with hydralazine. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with hydralazine.
Tell your provider if you are taking these medications or supplements:
You should also mention medical conditions such as:
If you are pregnant, planning to become pregnant, or breastfeeding, consult your healthcare provider before using hydralazine to assess potential risks and benefits.
Take hydralazine exactly as prescribed by your healthcare provider. Do not exceed the recommended dose or duration of treatment.
Hydralazine should be taken with or without food based on your healthcare provider's advice. It should either be taken consistently with food or taken consistently without food to ensure consistent absorption. It is important to follow their instructions for optimal effectiveness.
Avoid alcohol and activities that require alertness until you understand how hydralazine affects you, as it can cause dizziness.
Store hydralazine at room temperature, away from moisture and heat. Keep it out of reach of children.
In case of a hydralazine overdose, seek medical attention immediately. Symptoms of overdose may include severe headache, rapid heartbeat, severe dizziness, cold or clammy skin, and fainting. If you suspect an overdose, contact the poison control helpline at 1-800-222-1222 or call emergency services.
Hydralazine is available in the following forms:
The typical starting dose of hydralazine varies depending on the condition being treated, the severity of symptoms, and individual patient factors. It is important to follow your healthcare provider's instructions regarding dosage and administration.
For hypertension, the typical starting dose may be:
The dosage may be gradually increased based on the response and tolerance to the medication. Your healthcare provider will determine the most appropriate dose based on your medical history, current medications, and response to the medication.
Hydralazine should be taken exactly as prescribed by your healthcare provider. Do not exceed the recommended dose or duration of treatment without consulting your provider.
If you have any questions about your dosage or how to take this medication, contact your healthcare provider or pharmacist. If you want to talk to a provider right away, consider booking an online doctor appointment on Sesame to discuss your concerns.
If you miss 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. Do not double the dose to make up for a missed one.
Maintain a consistent dosing schedule to ensure the effectiveness of hydralazine in managing your hypertension.
Continue taking hydralazine as prescribed by your healthcare provider, even if you start feeling better. Do not stop the medication abruptly without consulting your provider, as it may lead to a recurrence of symptoms or other complications.
Complete the full course of treatment as directed to minimize the risk of relapse.
If you have any concerns or questions about your medication, discuss them with your healthcare provider for personalized guidance and recommendations.
Store hydralazine according to the instructions provided by your healthcare provider or pharmacist. Keep it at room temperature, away from moisture, heat, and light. Ensure the container is tightly closed and out of reach of children.
Do not use expired medication or medications that appear damaged or discolored. If you have any questions about storage, consult your healthcare provider or pharmacist for guidance.