What the label lists and what reports show
Hydralazine and isosorbide dinitrate side effects
Hydralazine and isosorbide dinitrate's FDA label: “Most common adverse reactions (≥ 5% more on BiDil than on placebo) were headache and dizziness ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Azurity Pharmaceuticals, Inc.” FAERS holds 428 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is renal failure (54 reports).
- Generic listed
Check it at the source: the hydralazine and isosorbide dinitrate FDA label on DailyMed (effective November 30, 2025, Azurity Pharmaceuticals, Inc.); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions (≥ 5% more on BiDil than on placebo) were headache and dizziness ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Azurity Pharmaceuticals, Inc.
Table 1. Adverse Reactions Occurring in the A-HeFT Study in ≥ 2% of Patients Treated with BiDil.
| Reaction | BiDil (N=517) % | Placebo (N=527) % |
|---|---|---|
| Headache | 50 | 21 |
| Dizziness | 32 | 14 |
| Asthenia | 14 | 11 |
| Nausea | 10 | 6 |
| Hypotension | 8 | 4 |
| Sinusitis | 4 | 2 |
| Ventricular tachycardia | 4 | 2 |
| Paresthesia | 4 | 2 |
| Vomiting | 4 | 2 |
| Amblyopia | 3 | 1 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedMost common adverse reactions (≥ 5% more on BiDil than on placebo) were headache and dizziness ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Azurity Pharmaceuticals, Inc. at 1-800-461-7449 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice. BiDil has been evaluated for safety in 517 heart failure patients in A-HeFT. A total of 317 of these patients received BiDil for at least 6 months, and 220 received BiDil for at least 12 months. In A-HeFT, 21% of the patients discontinued BiDil for adverse reactions compared to 12% who discontinued placebo. Overall, adverse reactions were more common in BiDil -treated than in placebo-treated patients. Table 1 lists adverse reactions reported with an incidence, after rounding, ≥ 2% higher on BiDil than on placebo in A-HeFT, regardless of causality. The most common reasons for discontinuing BiDil in the A-HeFT trial was headache (7%). Table 1. Adverse Reactions Occurring in the A-HeFT Study in ≥ 2% of Patients Treated with BiDil.
Source: FDA drug label, Azurity Pharmaceuticals, Inc., effective November 30, 2025 (SPL set e1e63cd5-d1e4-4af5-bad5-1ad41ea46b00), via openFDA; the full label on DailyMed
What do FAERS reports show?
428 reports list hydralazine and isosorbide dinitrate among the medicines taken, each a report of something that happened, not proof the medicine caused it; 66 are coded as a death and 168 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 24 reactions below, 9 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Hydralazine and isosorbide dinitrate: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions