Prescription medication · Vasodilator
hydralazine
Also sold as Apresoline. Hydralazine is used to treat high blood pressure (hypertension).
Data updated 2026-05-15
- 28,498
- FDA reportsModerately reported
- 3
- InteractionsFew interactions
- 1
- Recall record
What the data shows
hydralazine (Apresoline) is a prescription Vasodilator, reported at a middle-of-the-pack volume (28,498 FDA reports), with 3 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
hydralazine (Apresoline) is a prescription Vasodilator. Hydralazine is used to treat high blood pressure (hypertension).
Hydralazine is a drug that lowers blood pressure by relaxing blood vessels. It can be used alone or with other medications.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Generic Price
$0.03/unit
Generic Available
Yes (21 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Hydralazine is used to treat high blood pressure (hypertension).
Common side effects
Headache, Loss of appetite, Nausea
Key warnings
Taking high doses of hydralazine can cause a drug-induced lupus erythematosus (L.
The sections below are summarized in plain English from hydralazine's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Hydralazine works by relaxing the muscles in your blood vessels. This allows blood to flow more easily. As a result, your blood pressure goes down.
How to Take It
Start with a low dose and increase it slowly as directed by your doctor. You will likely start with 10 mg four times a day for 2-4 days. Then, your doctor may increase the dose to 25 mg four times a day for the rest of the first week. In the second week, the dose may increase to 50 mg four times a day. Take this medicine exactly as prescribed by your doctor.
This is a plain-language summary of hydralazine's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
Tell your doctor if you are pregnant or plan to become pregnant. It is not known if hydralazine will harm an unborn baby. Talk to your doctor about the risks and benefits of taking hydralazine during pregnancy or while breastfeeding.
This is a plain-language summary of hydralazine's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
This is a plain-language summary of hydralazine's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store hydralazine tablets at room temperature (68° to 77°F) in a tightly closed, light-resistant container, and keep out of reach of children.
Side Effects (from patient reports)
Based on 28,498 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for hydralazine, by number of reports
- Long-term kidney disease
Long-term kidney disease
2,819 reports
- Sudden kidney damage
Sudden kidney damage
2,616 reports
- Kidney failure
Kidney failure
2,097 reports
- Final stage of kidney failure
Final stage of kidney failure
1,585 reports
- Tiredness
Tiredness
1,541 reports
- Difficulty breathing
Difficulty breathing
1,535 reports
- Diarrhea
Diarrhea
1,406 reports
- Nausea
Nausea
1,334 reports
- Death
Death
1,316 reports
- High blood pressure
High blood pressure
1,312 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for hydralazine each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where hydralazine sits
hydralazine has more FDA adverse-event reports than 62% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is hydralazine; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 28,498 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 1995–2025.
Total Reports
28,498
Reports Mentioning Death
3,510
12.3% of reports — not proof of cause
Hospitalization Reports
12,190
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | CHRONIC KIDNEY DISEASE | 2,819 |
| 2 | ACUTE KIDNEY INJURY | 2,616 |
| 3 | RENAL FAILURE | 2,097 |
| 4 | END STAGE RENAL DISEASE | 1,585 |
| 5 | FATIGUE | 1,542 |
| 6 | DYSPNOEA | 1,535 |
| 7 | DIARRHOEA | 1,407 |
| 8 | NAUSEA | 1,337 |
| 10 | DEATH | 1,316 |
| 11 | HYPERTENSION | 1,312 |
| 13 | ANTI-NEUTROPHIL CYTOPLASMIC ANTIBODY POSITIVE VASCULITIS | 1,005 |
| 14 | ASTHENIA | 973 |
| 15 | DIZZINESS | 958 |
| 16 | HEADACHE | 943 |
| 17 | CARDIAC FAILURE CONGESTIVE | 884 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Taking high doses of hydralazine can cause a drug-induced lupus erythematosus (L.E.) cell syndrome. Your doctor will monitor your dose to avoid this.
Known Drug Interactions
Although not studied with alosetron, inhibition of N-acetyltransferase may have clinically relevant consequences for drugs such as isoniazid, procainamide, and hydralazine.
Mechanism: Alosetron may interfere with the way your body processes hydralazine, potentially leading to higher drug levels.
What to do: Talk to your doctor about monitoring your blood pressure and watching for any new symptoms.
Other Cardiovascular Agents Enalapril maleate has been used concomitantly with beta adrenergic-blocking agents, methyldopa, nitrates, calcium-blocking agents, hydralazine, prazosin and digoxin without evidence of clinically significant adverse interactions.
Mechanism: These two blood pressure medicines work in different ways to relax your blood vessels and have not been shown to cause harmful interactions when used together.
What to do: These drugs are generally safe to take together, but you should still watch for signs of very low blood pressure like dizziness.
Pindolol has been used with a variety of antihypertensive agents, including hydrochlorothiazide, hydralazine, and guanethidine without unexpected adverse interactions.
Mechanism: These two blood pressure medicines can be used together safely. They do not have any harmful interactions when taken at the same time.
What to do: You can take these medications together as prescribed. Your doctor will monitor your blood pressure to ensure the treatment is working.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
Can I stop taking hydralazine if I feel better?
Will hydralazine cure my high blood pressure?
Can I drink alcohol while taking hydralazine?
What should I do if I feel dizzy after taking hydralazine?
Does hydralazine interact with other medications?
Can hydralazine cause weight gain?
How long does it take for hydralazine to start working?
Can I take hydralazine if I have kidney problems?
Is it safe to drive while taking hydralazine?
What are the symptoms of L.E. cell syndrome?
What are the common side effects of hydralazine?
Does hydralazine interact with other medications?
What drug class is hydralazine?
Is hydralazine safe during pregnancy?
Has hydralazine been recalled?
Active Recalls
CGMP Deviations: Firm went out of business and could no longer continue stability studies.
Akorn, Inc.
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What the FDA Data Shows for hydralazine
The FDA label for hydralazine (sold under brand names such as Apresoline) classifies it as a prescription-only medication in the Vasodilator class. Hydralazine is used to treat high blood pressure (hypertension). Official labeling lists 7 commonly reported side effects, including Headache, Loss of appetite, Nausea.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 28,498 voluntary reports. The database also lists 3 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated minor severity. NADAC pricing from CMS shows a generic unit cost of $0.03.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history (currently 1 recall record on file), and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: July 1, 2025
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages