hydralazine
Hydralazine is a medication that's used to lower blood pressure. It's less commonly used for blood pressure, but it can be helpful when other first-choice medications aren't working. The dosage varies quite a bit; not everyone will take the same dose, but this medication is typically taken a few times a day. Common side effects include headache, stomach upset, and a fast heart rate. Hydralazine is available as a lower-cost generic tablet (there's no brand-name version).
What is Hydralazine?
What is Hydralazine used for?
How Hydralazine works
Hydralazine is known as a vasodilator. This class of medications works by relaxing your blood vessels, which then lowers your blood pressure.
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What are the side effects of Hydralazine?
Common Side Effects
- Headache
- Nausea
- Vomiting
- Diarrhea
- Lack or loss of appetite
- Rapid or abnormal heartbeat
- Chest pain
Other Side Effects
- Constipation
- Low blood pressure
- Dizziness
- Tingling, burning, or numbness in hands or feet
- Skin redness or warm skin (flushing)
- Difficulty urinating
- Rash
Serious Side Effects
- Heart attack: chest pain or pressure; shortness of breath; sweating; nausea; uncomfortable sensation in your arms, neck, or jaw
Source: DailyMed
The following side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
More common
Arm, back, or jaw pain
chest pain or discomfort
chest tightness or heaviness
fast, pounding, or irregular heartbeat or pulse
shortness of breath
sweating
Less common
Black, tarry stools
blindness or vision changes
blisters on the skin
blurred vision
burning of the face or mouth
burning, crawling, itching, numbness, painful, prickling, "pins and needles", or tingling feelings
chills
clumsiness or unsteadiness
confusion
difficult or labored breathing
dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
fever and sore throat
general feeling of discomfort or illness or weakness
joint pain
lower back or side pain
numbness, tingling, pain, or weakness in the hands or feet
painful or difficult urination
pale skin
shakiness in the legs, arms, hands, or feet
skin rash or itching
swelling of the feet or lower legs
swollen, painful, or tender lymph glands in the neck, armpit, or groin
tightness in the chest
trembling or shaking of the hands or feet
ulcers, sores, or white spots in the mouth
unusual bleeding or bruising
unusual tiredness or weakness
weakness in hands or feet
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
Feeling of warmth
headache
redness of the face, neck, arms, and occasionally, upper chest
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Pros and cons of Hydralazine
Pros
Good option to lower blood pressure when other first-choice medications don't work
Can take with other blood pressure medications
Available as a lower-cost generic version
Cons
Need to take multiple times a day, which can be hard to remember
Might cause symptoms similar to lupus at higher doses
Shouldn't use if you have certain types of heart disease because there's a risk for heart attack
Pharmacist tips for Hydralazine
You can take hydralazine with food or without food. Food can affect the amount of medication in your body. So whichever you decide, it's important to stay consistent so that your body gets about same amount of medication each day. Either always take hydralazine with food or always take it without food.
If you're checking your blood pressure at home, keep a record of your measurements. Let your provider know if it hasn't improved after 1 week because they might need to adjust your medication.
Hydralazine can cause low blood pressure when you move from a sitting or lying position to a standing position. Make sure that you get up slowly to prevent feeling dizzy or lightheaded or falling. This drop in blood pressure when standing up should go away after a few days, but talk to your provider if it doesn't. Your provider might change your dose or recommend a different medication.
Let your provider know if you develop a fever, rash on your cheeks, or pain in your joints and muscles while taking hydralazine. These could be lupus-like symptoms that the medication can cause. Your provider might recommend that you take a different blood pressure medication instead.
It's important to follow up with your blood work because sometimes this medication can lower your red blood cells and your white blood cells. This can cause dizziness, tiredness, and even raise your chance of infections.
If you've missed a dose of hydralazine and it's almost time for your next dose, skip the missed dose. Wait to take your next dose at your usual time. If you're unsure, ask your pharmacist or provider for guidance on what to do if you forget to take hydralazine.
Frequently asked questions about Hydralazine
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What are the risks and warnings for Hydralazine?
Hydralazine can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Drug-induced lupus-like symptoms
In rare cases, hydralazine caused some people to develop symptoms that look like systemic lupus erythematosus (SLE), also known as lupus. Symptoms can include joint pain, rash on the cheeks, and fevers. Most of the time, these symptoms go away when you stop the medication. But sometimes, it can take a longer time to go away. If you develop symptoms, let your provider know right away so that they can switch you to another medication.
Blood problems
Some people taking hydralazine have developed blood problems that lower the amounts of certain cells in your blood, including red and white blood cells. While this is rare, an imbalance in these cells can cause dizziness, tiredness, and even raise your chance of infections. Your provider might want to check your cell counts through blood work before and while you're taking this medication.
Numbness or tingling of feet and hands
Hydralazine can affect your nerves and cause numbness, tingling, or burning sensations in your hands or feet. If you have these symptoms, talk to your provider. They might recommend that you take vitamin B6 supplements with help treat these symptoms.
Heart attack and effects on blood circulation
Risk factors: Coronary artery disease (heart disease) | History of stroke | Heart valve problems
Hydralazine might not be the best choice for people who've had a heart attack because it's possible for the medication to cause a heart attack. In addition, because hydralazine helps relax your blood vessels, it might also bump up your blood flow. This can sometimes cause problems if you have heart valve issues or have had a stroke. Talk to your provider if you have heart disease or have had a stroke in the past.
Hydralazine dosage forms
Typical dosing for Hydralazine
The typical starting dose is 10 mg by mouth four times daily for the first 2 to 4 days. Then, your provider will probably raise your dose to 25 mg by mouth four times daily for the rest of the first week of treatment.
From the second week and on, your provider might raise your dose to 50 mg by mouth four times daily.
Note: Your provider might prescribe a slightly different dose based on treatment guidelines for blood pressure from the American College of Cardiology/American Heart Association (usually 100 mg to 200 mg per day, split into two or three doses).
Your provider will work with you to find the lowest possible dose that works the best at lowering your blood pressure. The maximum dose of hydralazine is a total of 300 mg in one day. But most people don't need to take more than 200 mg in one day.
Hydralazine is also available as an injection that's given through the vein or into the muscle by a healthcare provider.
More on Hydralazine dosage forms
Interactions between Hydralazine and other drugs
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
How much does Hydralazine cost?
Hydralazine contraindications
Coronary artery disease (CAD)
Mitral valvular rheumatic heart disease (heart valve condition)
What are alternatives to Hydralazine?
High blood pressure
Heart failure
Lower the risk for death after a heart attack
High blood pressure
Swelling in the body from fluids (edema), in addition to other medications
What is the latest news about Hydralazine?
Hydralazine images
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References
Best studies we foundAkorn. (2022). HYDRALAZINE HYDROCHLORIDE injection [package insert]. DailyMed.
American Heart Association. (2023). Low blood pressure - when blood pressure is too low.
American Heart Association. (2023). Types of Blood Pressure Medications.
Chartwell RX, LLC. (2023). HYDRALAZINE HYDROCHLORIDE tablet, film coated [package insert]. DailyMed.
Dass, C., et al. (2023). Rheumatic heart disease. StatPearls.
Ghazi, Lama, et al. (2022). Blood pressure response to commonly administered antihypertensives for severe inpatient hypertension. PLOS One.
Herman, L. L., et al. (2023). Hydralazine. StatPearls.
MedlinePlus. (2017). Hydralazine.
The American College of Obstetricians and Gynecologists Committee on Practice Bulletins—Obstetrics. (2018). Gestational hypertension and preeclampsia. Obstetrics & Gynecology.
Whelton, P. K., et al. (2017). 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: A report of the American College of Cardiology/American Heart Association Task Force on clinical practice guidelines. Hypertension.
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