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.
Drug facts
Side effects of Hydralazine
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
- Headache
- Nausea
- Vomiting
- Diarrhea
- Lack or loss of appetite
- Rapid or abnormal heartbeat
- Chest pain
Less Common Side Effects
- Constipation
- Low blood pressure
- Dizziness
- Tingling, burning, or numbness in hands or feet
- Skin redness or warm skin (flushing)
- Difficulty urinating
- Rash
Hydralazine serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Heart attack: chest pain or pressure; shortness of breath; sweating; nausea; uncomfortable sensation in your arms, neck, or jaw
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The following Hydralazine 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.
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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.
Common questions about Hydralazine
No, hydralazine isn't a diuretic (water pill). It doesn't work to remove excess fluids from your body to lower blood pressure like diuretics do. Instead, hydralazine relaxes your blood vessels to do so. You might be thinking of another blood pressure medication called hydrochlorothiazide. Hydrochlorothiazide is a diuretic and is actually a first-choice blood pressure medication. There's a chance that your provider might have you take hydralazine along with hydrochlorothiazide if you need additional blood pressure control; they work differently to lower your blood pressure.
No, hydralazine isn't a beta blocker. Hydralazine is a vasodilator that works by relaxing your blood vessels, which in turn lowers your blood pressure. Beta blockers (such as metoprolol and carvedilol) work differently to lower your blood pressure.
No, hydralazine doesn't typically lower your heart rate. In fact, hydralazine tends to make your heart rate faster. This happens because the medication turns on your sympathetic nervous system (which is related to your "fight-or-flight" response). This leads to a fast heart beat (heart rate). If hydralazine speeds up your heart rate too much, your provider might add on another medication (e.g., a beta blocker) to balance this out.
It's not exactly know how long hydralazine side effects last. But we can estimate that they shouldn't linger around for long since the medication doesn't last for a long time in your body. If you're stopping hydralazine completely, it can take about a day and a half for the medication to clear out of your system all the way (and thus any unpleasant side effects should stop). Let your provider know if any side effects that you have become bothersome. They can see whether it's better to switch you to a different blood pressure medication.
You might notice a drop in your blood pressure about 6 hours after you take a dose of hydralazine. But it might take weeks before you see the maximum benefit on your blood pressure. When you first start hydralazine (the first week or so), your provider will want you to follow up with them often to see how hydralazine affects your blood pressure. Your provider will adjust your dose so your blood pressure is at an acceptable level (not too high and not too low).
You might want to speak to a provider before taking your hydralazine dose if your blood pressure is already low and you feel dizzy, lightheaded, or weak. This medication can lower your blood pressure even more, make these effects worse, and can even be dangerous. Your hydralazine dose might need to be adjusted. Hydralazine also shouldn't be used if you've had a heart attack. This medication might cause heart attacks, so taking hydralazine might put you at risk of having another one. Talk to your provider before starting hydralazine if you have a history of heart disease to make sure it's safe for you to take.
If your provider instructs you to take hydralazine four times a day, take your dose about every 6 hours. If your provider told you to take the medication three times a day, take your dose about every 8 hours. Basically, spread out your doses evenly throughout the day; don't double up on doses since this could lead to more side effects.
If you're pregnant or planning to become pregnant, speak to your provider about the risks and benefits of taking hydralazine tablets. There's not enough data to know whether oral hydralazine is safe to take during pregnancy. Note that the intravenous (IV) version of hydralazine is commonly used to treat severe high blood pressure in pregnant women with preeclampsia in emergency situations. If you're in this situation, your provider will give this injection form of hydralazine into your veins.
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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
Tablet| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 10mg | 90 tablets | $4.00 | $0.04 |
| 25mg | 90 tablets | $4.00 | $0.04 |
| 100mg | 90 tablets | $16.40 | $0.18 |
| 50mg | 90 tablets | $4.00 | $0.04 |
Typical dosage 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
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?
$4.00
Hydralazine contraindications
Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Hydralazine will not be safe for you to take.
- Coronary artery disease (CAD)
- Mitral valvular rheumatic heart disease (heart valve condition)
What are alternatives to Hydralazine?
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