Hydralazine Hydralazine is an oral tablet used for hypertension. The medication is a vasodilator that can help lower blood pressure levels by relaxing blood vessels. Effective hypertension treatment can reduce the risk of heart attack, stroke and kidney issues. Read more about hypertension.
Start Consultation*Prescription treatment requires a virtual medical consultation with a medical provider to determine if a prescription is appropriate.
How to use this information
This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective or appropriate for you. This information is not individual medical advice and does not substitute for the advice of a medical provider. If you have any questions, go to your patient dashboard and request a callback for complete information about this product and your specific health needs.
Medication name




What you should know about Hydralazine
  • Hydralazine is used with or without other medications to treat high blood pressure.
  • Lowering high blood pressure helps prevent strokes, heart attacks and kidney problems.
  • Hydralazine belongs to a class of drugs called vasodilators. It works by relaxing blood vessels so blood can flow through the body more easily.
How to take Hydralazine
  • Take this medication by mouth with or without food, usually 2 to 4 times daily or as directed by your medical provider. The dosage is based on your medical condition and response to treatment. Your medical provider may start you at a low dose and gradually increase your dose. Follow their instructions carefully.
  • Use this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day. Keep taking this medication even if you feel well. Most people with high blood pressure do not feel sick. It may take up to several weeks before you get the full benefit of this drug.
  • Do not stop taking this medication without consulting your medical provider. Some conditions may become worse when the drug is suddenly stopped. Your dose may need to be gradually decreased.
Potential side effects
  • Headache, pounding or fast heartbeat, loss of appetite, nausea, vomiting, diarrhea or dizziness may occur as your body adjusts to the medication. If any of these effects last or get worse, tell your medical provider or pharmacist right away.
  • To reduce the risk of dizziness, get up slowly when rising from a sitting or lying position.
  • Remember that this medication has been prescribed because your medical provider has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not experience serious side effects.
  • In rare cases, this medication may cause nerve problems. Tell your medical provider right away if you experience numbness or tingling. They may recommend a vitamin B6 supplement (Pyridoxine).
  • Tell your medical provider right away if you experience any serious side effects, including:

    • Severe tiredness
    • Aching or swollen joints
    • Rash on the nose and cheeks
    • Swollen glands
    • Signs of kidney problems, such as changes in amount of urine or bloody/pink urine
    • Signs of infection, such as a sore throat that doesn't go away, fever or chills
    • Easy bruising or bleeding
  • Get medical help right away if you experience any very serious side effects, including chest, jaw or left arm pain.
  • A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

    • Rash
    • Itching or swelling, especially of the face/tongue/throat
    • Severe dizziness
    • Trouble breathing
  • This is not a complete list of possible side effects. If you notice other effects not listed above, request a callback for medical advice. You may also report side effects to the FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

Precautions to be aware of
  • Before taking Hydralazine, tell your medical provider or pharmacist if you are allergic to it or have any other allergies, including a Tartrazine allergy. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Go to your patient dashboard and request a callback for more details.
  • Before using this medication, tell your medical provider or pharmacist your medical history, especially of:

    • Lupus
    • Congestive heart failure (CHF)
    • Prior diagnosis of aneurysm or dissection of aorta
    • Heart problems, such as coronary artery disease, recent heart attack or rheumatic heart disease of the mitral valve or aortic valve
    • Blood vessel problems
    • Previous stroke
    • Kidney problems
  • There is the potential for bone marrow suppression, including a drop in blood cells.
  • This drug may make you dizzy. Alcohol or marijuana (cannabis) can exacerbate the effect. Do not drive, use machinery or do anything that requires alertness until you can do it safely. Limit alcoholic beverages. Talk to your medical provider if you are using marijuana.
  • Before having surgery, tell your doctor or dentist that you are taking this medication.
  • Older adults may be more sensitive to the side effects of this medication, especially dizziness (which can increase the risk of falls).
  • During pregnancy, this medication should be used only when there is a clear need. Discuss the risks and benefits with your medical provider.
  • This medication passes into breast milk, but is unlikely to harm a nursing infant. Consult your medical provider before breastfeeding.
Drug interactions
  • Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions.
  • Keep a list of all the products you use—including prescription/nonprescription drugs and herbal products—and share it with your medical provider and pharmacist. 
  • Do not start, stop or change the dosage of any medicines without your medical provider's approval.
  • This drug may interact with:

    • Alprazolam
    • Cholesterol-lowering agents, including statins
    • Colchicine
    • Lithium
    • Licorice 
    • Metronidazole
    • Oxycodone
    • Prednisone
    • Red yeast rice
  • Some products have ingredients that could raise your heart rate or blood pressure or worsen your heart failure. Tell your pharmacist what products you are using, and ask how to use them safely—especially cough-and-cold products, diet aids or NSAIDs, such as Ibuprofen and Naproxen.

What to do in the event of an overdose

Symptoms of overdose may include severe dizziness, fainting, flushing, chest/jaw/left arm pain or irregular heartbeat.

If someone has overdosed and is experiencing serious symptoms—such as passing out or trouble breathing—call 911. If symptoms from taking this medication are less severe, call your local poison control center at 1-800-222-1222 right away.

Additional notes
  • Do not share this medication with others.
  • Lifestyle changes, such as stress reduction programs, exercise and dietary changes, may help this medication work better. Talk to your medical provider or pharmacist about lifestyle changes that might benefit you.
  • Lab and/or medical tests (such as complete blood count) may be performed while you are taking this medication. Keep all medical and lab appointments. Consult your medical provider for more details.
  • Have your blood pressure checked regularly while taking this medication. Learn how to monitor your own blood pressure, and share the readings with your medical provider.
What to do if you miss a dose

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

How to store this medication
  • Store at room temperature away from light and moisture. Do not store in the bathroom.
  • Keep all medications away from children and pets.
  • Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more information.
Treatment for
Generic Name
Drug Class

What is Dr. B?

At Dr. B, you can get convenient medical care—including prescription treatments—right from home. We believe everyone deserves affordable access to healthcare. That's why an online consultation with a licensed provider is only $15. Need more financial support? Dr. B also offers a No-Cost Care* option for those who qualify.

* Financial hardship assistance available for those who qualify

Send your prescription anywhere

Walgreens logo Amazon logo Walmart logo CVS logo

Send your prescription to thousands of pharmacies for pickup or online delivery. Your choice.

Senior woman using smartphone standing on kitchen during morning time

How Dr. B treats hypertension

Health assessment

Tell us about your condition with a $15 online consultation—no video call necessary.

Provider review

A medical provider will review your information and prescribe treatment, if appropriate.

Get your medication

Pick up and pay for the medication at the pharmacy of your choice. Or, get it delivered.

How much will it cost?

Dr. B offers online consultations for $15—which is less than most copays. If a hypertension prescription is appropriate, your out-of-pocket medication cost will depend on your insurance and where you decide to get your prescription filled.

Dr. B logo
Online visit with Dr. B
CVS Pharmacy logo
Walmart logo
Rite Aid logo
Costco Wholesale logo
Walgreens logo
Prices vary


More hypertension Options

More options...

“The process could not have been easier. My chart was reviewed by a licensed professional and I was able to pick up my prescription at my preferred local pharmacy within a few hours.”

Meghan E. from Florida

Verified Patient

“Dr. B made it easy and affordable to get my medication. I was able to get a prescription without having to go through the hassle of having to make a doctor’s appointment, take time off work, etc., all while knowing that there is a trusted medical professional taking care of me.”

Marsha D. from Florida

Verified Patient

“The process for the Dr. B birth control was very easy and efficient. The website made getting prescription birth control easily accessible, especially for someone like me who does not have an established primary doctor in the area yet.”

Jennifer F. from Florida

Verified Patient

Featured On

The New York Times logo
Axios logo
TIME logo
Bloomberg logo
Fast Company logo
ABC logo