BiDil Hydralazine hydrochloride and Isosorbide dinitrate 37.5 mg; 20 mg Tablet, Film Coated, 90-count — NDC 24338-010-09 (Billing 24338-0010-09)
This is a package of 90 tablets of BiDil Hydralazine hydrochloride and Isosorbide dinitrate 37.5 mg; 20 mg Tablet, Film Coated from Azurity Pharmaceuticals, Inc., marketed since Dec 2012 and currently FDA-listed; retail pharmacies pay about $4.35 per tablet (NADAC). It is this product's only package size.
NDC database record
One package, one record: these facts belong to NDC 24338-010-09 alone.
- Record
- FDA NDC Directory package listing · Human prescription drug
- Code segments
- 24338 labeler · 010 product · 09 package
- Package marketed since
- Aug 31, 2020
- Sample package
- No — commercial package
- Listing certified through
- Dec 31, 2027
- Billing quantity
- 90 EA per package
- Barcode (UPC)
- 0324338010099
- Medicaid fills, this package
- 552 prescriptions in the last four reported quarters
- FDA record last changed
- Jul 24, 2026
Identity & classification
Regulatory identifiers FDA, NLM and CMS codes for this package
Drug-database identifiers Medi-Span GPI and First Databank GCN / HICL / AHFS classification
- GSN (GCN sequence number): 059324
- GCN: 24925
- GPI-14 (Medi-Span): 40995002400320
- HICL (First Databank): 033009
- AHFS class code: 24:08.08.00
- RxCUI (RxNorm): 905377
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 8, 2026
- FDA label on DailyMed · label index refreshed Oct 6, 2026
- RxNorm (NLM RxNav) · catalog refreshed Oct 1, 2026
- Medi-Span GPI (licensed)
- First Databank (licensed) · refreshed Oct 8, 2026
RxNorm drug class
This medicine belongs to the Arteriolar Vasodilator class.
Where does this data come from?
- RxClass (NLM) · catalog refreshed Oct 1, 2026
Clinical
Hydralazine is used to treat high blood pressure. Hydralazine is in a class of medications called vasodilators. It works by relaxing the blood vessels so that blood can flow more easily through the body. High blood pressure is a common condition and when not treated, can cause damage to the brain, heart, blood vessels, kidneys and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressur...
Read the full MedlinePlus article ↗- It treats heart failure as an add-on to your other standard heart failure medicines. It is approved for people who self-identify as Black. In studies it improved survival, delayed...
- You take it by mouth three times a day. Your prescriber will usually start low and raise the dose as you tolerate it. If side effects are hard to manage, tell them, because the dos...
- Headache and dizziness are the most common, and headache is the main reason people stopped it in the trial. Nausea, weakness and low blood pressure can also happen. Tell your presc...
- Call if you feel faint, have chest pain or a racing heartbeat, or notice numbness or tingling. Those can be signs of low blood pressure, heart strain, or nerve irritation from hydr...
Patient education
Supplement & herbal interactions
Where does this data come from?
- MedlinePlus (NLM) · refreshed Oct 1, 2026
- FDA label on DailyMed · label index refreshed Oct 6, 2026
Ask a licensed pharmacist directly — free, answered by our team.
Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per ea | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | $4.345 | $391.07 / 90 tablets |
| Medicaid paysCMS SDUD · 12 mo | $4.40 | $396.05 / 90 tablets |
| Medicare drug plans payPart D · Q2 2026 | $4.67 | $420.64 / 90 tablets |
Where does this data come from?
- CMS NADAC weekly file · file of Oct 7, 2026
- CMS ASP pricing files · refreshed Sep 20, 2026
- CMS Medicaid State Drug Utilization Data · through Q1 2026
- CMS Part D plan pricing files · refreshed Sep 24, 2026
- VA National Acquisition Center price file
Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Marketing end | Status |
|---|---|---|---|---|
| 24338-0010-09 You're viewing this Main listing | 90 TABLET, FILM COATED in 1 BOTTLE | 2020-08-31 | — | Active |
Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| isosorbide dinitrate and hydralazine hydrochloride 37.5 mg/1; 20 mg 52536-0006-09 | Wilshire | 90 tablets | $0.714 | AB | Availability likely | save 84% |
| isosorbide dinitrate and hydralazine hydrochloride 20 mg/1; 37.5 mg 72319-0012-03 | i3 | 90 tablets | $0.714 | AB | Availability likely | save 84% |
| Isosorbide dinitrate and hydralazine hydrochloride 37.5 mg/1; 20 mg 50742-0246-18 | Ingenus | 180 tablets | $1.576 | AB | FDA listed | save 64% |
| BiDil 37.5 mg/1; 20 mgthis 24338-0010-09 | Azurity | 90 tablets | $4.345 | AB | Availability likely | — |
| isosorbide dinitrate and hydralazine hydrochloride 37.5 mg/1; 20 mg 72162-2343-09 | Bryant | 90 tablets | — | AB | FDA listed | — |
| isosorbide dinitrate and hydralazine hydrochloride 20 mg/1; 37.5 mg 73141-0012-03 | A2A | 90 tablets | — | AB | FDA listed | — |
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 8, 2026
- FDA Orange Book · refreshed Oct 3, 2026
- CMS NADAC weekly file · file of Oct 7, 2026
Availability & generic status
The FDA lists approved generic versions of this medicine, but that does not always mean a pharmacy can get one today. Patent rules, launch agreements, supply and pricing can affect when generics actually arrive.
Where does this data come from?
- FDA Orange Book · refreshed Oct 3, 2026
What it looks like
Where does this data come from?
- FDA label on DailyMed · label index refreshed Oct 6, 2026
Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
🧪 Avoiding an ingredient? See Hydralazine / Isosorbide Dinitrate inactive ingredients by manufacturer: every current product's list side by side, so you can ask your pharmacy for the version that does not list it.
💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.
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UNII LMI26O6933
Alumina is a white powder form of aluminum oxide. It's used as a filler to add bulk to tablets and capsules, and sometimes as a thickening or anti-caking agent in powdered formulations.
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UNII 3SY5LH9PMK
Anhydrous lactose is a milk sugar with no water content. It acts as a filler and binder in tablets and capsules, adding bulk and helping ingredients stick together.
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UNII H77VEI93A8
A synthetic yellow dye used to color medications. It helps identify the drug and make it visually distinctive, with no effect on how the medicine works.
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UNII 3NXW29V3WO
Hypromellose is a plant-based thickener made from cellulose. It's used in medicines as a binder to hold ingredients together, a coating for tablets, and a thickener for liquids.
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UNII 70097M6I30
Magnesium stearate is a salt made from magnesium and stearic acid, a fatty substance. It's used in tablets and capsules as a lubricant and glidant to help ingredients flow smoothly during manufacturing and prevent sticking.
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UNII OP1R32D61U
Microcrystalline cellulose is a purified form of cellulose, a natural fiber from plant sources. It acts as a binder and filler in tablets and capsules, helping hold ingredients together and give the medicine its shape and size.
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UNII 3WJQ0SDW1A
Polyethylene glycol is a synthetic liquid or solid polymer used in medicines as a solvent, lubricant, and humectant. It helps dissolve active ingredients, reduces friction during manufacturing, and retains moisture in the final product.
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UNII 6OZP39ZG8H
Polysorbate 80 is a synthetic emulsifier derived from sorbitol and oleic acid. It helps mix oil and water-based ingredients together in medications and improves how the product disperses in the body.
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UNII ETJ7Z6XBU4
Silicon dioxide is a naturally occurring mineral used as a glidant and anti-caking agent. It helps powder ingredients flow smoothly and prevents clumping during manufacturing and storage.
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UNII 5856J3G2A2
A starch-based powder made from potatoes and processed with sodium. It acts as a disintegrant, helping the tablet or capsule break apart quickly in the stomach so the medicine can be absorbed.
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UNII 15FIX9V2JP
Titanium dioxide is a bright white mineral powder commonly used as a colorant and opacifying agent. It makes pills and tablets white or lighter in color and helps make coatings non-transparent.
11 inactive ingredients listed in the exact product block matched to this NDC.
Where does this data come from?
ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.- FDA label on DailyMed · label index refreshed Oct 6, 2026
- FDA openFDA NDC Directory · synced Oct 8, 2026
Inactive ingredient FAQ
Are inactive ingredients the same for every manufacturer?
Why might an inactive ingredient be missing?
Can inactive ingredients matter?
Manufacturer & labeler
More NDCs from Azurity Pharmaceuticals, Inc. labeler code 24338
- Widaplik telmisartan, amlodipine and indapamide 10 mg; 1.25 mg; .625 mg Tablet NDC 24338-001-30
- Widaplik telmisartan, amlodipine and indapamide 20 mg; 2.5 mg; 1.25 mg Tablet NDC 24338-002-30
- Widaplik telmisartan, amlodipine and indapamide 40 mg; 5 mg; 2.5 mg Tablet NDC 24338-003-30
- BRYNOVIN Sitagliptin Hydrochloride Oral 25 mg/mL Solution NDC 24338-017-01
- MYHIBBIN MYCOPHENOLATE MOFETIL 200 mg/mL Suspension NDC 24338-018-01
- ARYNTA lisdexamfetamine dimesylate oral 10 mg/mL Solution NDC 24338-019-01
- Evekeo Amphetamine Sulfate 5 mg Tablet NDC 24338-022-03
- Evekeo Amphetamine Sulfate 10 mg Tablet NDC 24338-026-03
- Gliadel carmustine 7.7 mg Wafer NDC 24338-050-08
Where does this data come from?
- FDA openFDA NDC Directory · synced Oct 8, 2026
- Drugs@FDA
Full prescribing information FDA SPL
🎯 Indications and Usage ▾
1 INDICATIONS AND USAGE BiDil is a combination of isosorbide dinitrate, a nitrate vasodilator, and hydralazine hydrochloride, an arteriolar vasodilator, indicated for: the treatment of heart failure as an adjunct therapy to standard therapy in self-identified black patients to improve survival, prolong time to hospitalization for heart failure and to improve patient-reported functional status ( 1.1 ) Limitations of use: There is little experience in patients with NYHA class IV heart failure ( 1.2 )
1.1Treatment of Heart Failure in Self-identified Black Patients BiDil is indicated for the treatment of heart failure as an adjunct to standard therapy in self-identified black patients to improve survival, to prolong time to hospitalization for heart failure, and to improve patient-reported functional status.
1.2Limitations of Use There is little experience in patients with NYHA class IV heart failure.
⏱️ Dosage and Administration ▾
2 DOSAGE AND ADMINISTRATION BiDil should be initiated at a dose of one BiDil Tablet, three times a day. Titrate to a maximum of two tablets three times daily, if tolerated. Although titration of BiDil can be rapid (3-5 days), some patients may experience side effects and may take longer to reach their maximum tolerated dose.
The dosage may be decreased to as little as one-half BiDil Tablet three times a day if intolerable side effects occur. Efforts should be made to titrate up as soon as side effects subside. One tablet three times a day titrated to a maximum tolerated dose up to two tablets three times a day ( 2 ) Dosage may be decreased to as little as one-half tablet three times a day if intolerable side effects occur.
Efforts should be made to titrate up as soon as side effects subside ( 2 )
💊 Dosage Forms and Strengths ▾
3 DOSAGE FORMS AND STRENGTHS The BiDil (20 mg isosorbide dinitrate and 37.5 mg hydralazine hydrochloride) tablets are orange, biconvex, approximately 8 mm in diameter, scored, film-coated, and debossed with "20" on one side over the score and " N " on the other side. Tablets (scored): 20 mg isosorbide dinitrate and 37.5 mg hydralazine hydrochloride ( 3 )
⛔ Contraindications ▾
4 CONTRAINDICATIONS BiDil is contraindicated in patients who are allergic to organic nitrates. Do not use BiDil in patients who are taking PDE-5 inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil. Concomitant use can cause severe hypotension, syncope, or myocardial ischemia [see Drug Interactions (7.1) ] .
Do not use BiDil in patients who are taking the soluble guanylate cyclase (sGC) stimulator riociguat. Concomitant use can cause hypotension. Patients who are allergic to organic nitrates ( 4 ) Use of phosphodiesterase type 5 (PDE5) inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil, or soluble guanylate cyclase (sGC) stimulator (riociguat).
( 4 )
⚠️ Warnings and Cautions ▾
5 WARNINGS AND PRECAUTIONS May cause symptomatic hypotension ( 5.1 ) Symptomatic Lupus Erythematosus Syndromes: Consider discontinuation if clinically appropriate ( 5.2 ) Myocardial ischemia and angina ( 5.3 ) Peripheral Neuritis : May be treated with Pyridoxine ( 5.4 )
5.1Hypotension Symptomatic hypotension, particularly with upright posture, may occur with even small doses of BiDil. Hypotension is most likely to occur in patients who have been volume or salt depleted; correct prior to initiation of BiDil [see Adverse Reactions (6.1) ] .
5.2Systemic Lupus Erythematosus Hydralazine hydrochloride has been reported to cause a drug-induced systemic lupus erythematosus (SLE) syndrome. Symptoms and signs usually regress when hydralazine hydrochloride is discontinued.
5.3Worsening Ischemic Heart Disease Hydralazine hydrochloride can cause tachycardia and hypotension potentially leading to myocardial ischemia and angina, particularly in patients with hypertrophic cardiomyopathy.
5.4Peripheral Neuritis Hydralazine hydrochloride has been associated with peripheral neuritis, evidenced by paresthesia, numbness, and tingling, which may be related to an antipyridoxine effect. Pyridoxine should be added to BiDil therapy if such symptoms develop.
🤒 Adverse Reactions ▾
6 ADVERSE REACTIONS 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. at 1-800-461-7449 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .
6.1Clinical 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.
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 In the V-HeFT I and II clinical studies, a total of 587 patients with heart failure were treated with the combination of isosorbide dinitrate and hydralazine hydrochloride. The type, pattern, frequency and severity of adverse reactions reported in these studies were similar to those reported in A-HeFT, described above and no unusual adverse reactions were reported.
6.2Postmarketing Experience The following adverse reactions have been identified during post-approval use of BiDil. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Use of BiDil: The following adverse reactions have been identified with use of BiDil.
Cardiac Disorders: Palpitations Ear and labyrinth disorders: Tinnitus, vertigo Eye Disorders: Eyelid edema, vision blurred Gastrointestinal Disorders: Abdominal discomfort, constipation General Disorders and Administration Site Conditions: Facial pain, flushing, chest discomfort, chest pain, peripheral edema Musculoskeletal and Connective Tissue Disorders: Pain in extremity, myalgia Nervous Disorders: Dysgeusia, hypoaesthesia, migraine, syncope Renal and Urinary Disorders: Chromaturia, pulmonary renal syndrome Respiratory, Thoracic and Mediastinal Disorders: Dyspnea Reproductive System and Breast Disorders: Erectile dysfunction Skin and Subcutaneous Tissue Disorders: Erythema, hyperhidrosis, pruritus, face swelling Use of Hydralazine Hydrochloride or Isosorbide Dinitrate: The following reactions have been reported with use of either hydralazine hydrochloride or isosorbide dinitrate.
Blood and Lymphatic System Disorders: Blood dyscrasias, agranulocytosis, purpura, eosinophilia, splenomegaly. Eye Disorders: Lacrimation, conjunctivitis. Gastrointestinal Disorders: Paralytic ileus.
Hepatobiliary Disorders: Hepatitis. Psychiatric Disorders: Psychotic reactions, disorientation. Renal and Urinary Disorders: Difficulty in urination.
🔄 Drug Interactions ▾
7 DRUG INTERACTIONS
7.1Phosphodiesterase Inhibitors BiDil is contraindicated in patients who are using a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), PDE5 inhibitors such as avanafil, sildenafil, vardenafil, and tadalafil have been shown to potentiate the hypotensive effects of organic nitrates. Do not use BiDil in patients who are taking the soluble guanylate cyclase (sGC) stimulator riociguat. Concomitant use can cause hypotension [see Contraindications (4) ] .
👥 Use in Specific Populations ▾
8 USE IN SPECIFIC POPULATIONS Geriatric Use: Isosorbide dinitrate and hydralazine may be eliminated more slowly in elderly patients. Initiate therapy at the low end of the dosing range ( 8.5 )
8.1Pregnancy Risk Summary There are no data on BiDil use in pregnant women, and insufficient data on its components (hydralazine and isosorbide dinitrate) to assess a drug-associated risk of major birth defects or miscarriage with first trimester use. Available published data on hydralazine use in pregnancy during the second and third trimesters have not shown an association with adverse pregnancy-related outcomes. Hydralazine hydrochloride is teratogenic in mice at 66 mg/kg and possibly in rabbits at 33 mg/kg (2 and 3 times the MRHD of BiDil on a body surface area basis).
Isosorbide dinitrate has been shown to cause a dose-related increase in embryo-toxicity (excess mummified pups) in rabbits at 70 mg/kg (12 times the MRHD of BiDil on a body surface area basis). All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.
Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk Pregnant women with heart failure are at increased risk for preterm birth. Clinical classification of heart disease may worsen with pregnancy and lead to maternal death and/or stillbirth.
8.2Lactation Risk Summary There are no data on the presence of BIDIL in human or animal milk, the effects on the breastfed infant or on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for BIDIL and any potential adverse effects on the breastfed child from BIDIL or from the underlying maternal condition.
8.4Pediatric Use The safety and effectiveness of BiDil in children have not been established.
8.5Geriatric Use Clinical studies of BiDil did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in response between elderly and younger patients. In general, dose selection for an elderly patient should start at the low end of the dosing range, reflecting the greater frequency of decreased hepatic and renal function, and of concomitant disease or other drug therapies.
Isosorbide dinitrate, its active metabolites, and hydralazine may be eliminated more slowly in elderly patients.
8.6Renal Impairment There are no studies of renal impairment using BiDil. No dose adjustment is required for hydralazine or isosorbide dinitrite [see Clinical Pharmacology (12.3) ] . Dialyzability of hydralazine has not been determined . Dialysis is not an effective method for removing isosorbide dinitrate or its metabolite isosorbide-5-mononitrate from the body.
8.7Hepatic Impairment The effect of hepatic impairment on the pharmacokinetics of hydralazine alone has not been determined.Isosorbide dinitrate concentrations increase in patients with cirrhosis. There are no studies of hepatic impairment using BiDil.
🤰 Pregnancy ▾
8.1Pregnancy Risk Summary There are no data on BiDil use in pregnant women, and insufficient data on its components (hydralazine and isosorbide dinitrate) to assess a drug-associated risk of major birth defects or miscarriage with first trimester use. Available published data on hydralazine use in pregnancy during the second and third trimesters have not shown an association with adverse pregnancy-related outcomes. Hydralazine hydrochloride is teratogenic in mice at 66 mg/kg and possibly in rabbits at 33 mg/kg (2 and 3 times the MRHD of BiDil on a body surface area basis).
Isosorbide dinitrate has been shown to cause a dose-related increase in embryo-toxicity (excess mummified pups) in rabbits at 70 mg/kg (12 times the MRHD of BiDil on a body surface area basis). All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.
Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk Pregnant women with heart failure are at increased risk for preterm birth. Clinical classification of heart disease may worsen with pregnancy and lead to maternal death and/or stillbirth.
🧒 Pediatric Use ▾
8.4Pediatric Use The safety and effectiveness of BiDil in children have not been established.
🧓 Geriatric Use ▾
8.5Geriatric Use Clinical studies of BiDil did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in response between elderly and younger patients. In general, dose selection for an elderly patient should start at the low end of the dosing range, reflecting the greater frequency of decreased hepatic and renal function, and of concomitant disease or other drug therapies.
Isosorbide dinitrate, its active metabolites, and hydralazine may be eliminated more slowly in elderly patients.
🆘 Overdosage ▾
10 OVERDOSAGE The signs and symptoms of overdosage with BiDil are expected to be those of excessive pharmacologic effect, i.e., vasodilatation, reduced cardiac output and hypotension, and signs and symptoms include headache, confusion, tachycardia, and generalized skin flushing. Complications can include myocardial ischemia and subsequent myocardial infarction, cardiac arrhythmia, and profound shock. Syncope, coma and death may ensue without appropriate treatment.
Human Experience: There are no documented cases of overdosage with BiDil. No deaths from acute poisoning have been reported. Treatment: There is no specific antidote.
Support of the cardiovascular system is of primary importance. Shock should be treated with plasma expanders, vasopressors, and positive inotropic agents. The gastric contents should be evacuated, taking adequate precautions to prevent aspiration.
These manipulations have to be carried out after cardiovascular status has been stabilized, since they might precipitate cardiac arrhythmias or increase the depth of shock. In patients with renal disease or congestive heart failure, therapy resulting in central volume expansion is not without hazard. Treatment of isosorbide dinitrate overdose in these patients may be difficult, and invasive monitoring may be required.
No data are available to suggest physiological maneuvers (e.g., maneuvers to change the pH of the urine) that might accelerate elimination of the components of BiDil. Dialysis is not effective in removing circulating isosorbide dinitrate. The dialyzability of hydralazine has not been determined.
Methemoglobinemia: Nitrate ions liberated during metabolism of isosorbide dinitrate can oxidize hemoglobin into methemoglobin. There are case reports of significant methemoglobinemia in association with moderate overdoses of organic nitrates. Methemoglobin levels are measurable by most clinical laboratories.
Methemoglobinemia could be serious in chronic heart failure patients because of already compromised vascular bed-tissue gas exchange dynamics. Classically, methemoglobinemic blood is described as chocolate brown, without color change on exposure to air. When methemoglobinemia is diagnosed, the treatment of choice is methylene blue, 1 to 2 mg/kg intravenously.
🧬 Clinical Pharmacology ▾
12 CLINICAL PHARMACOLOGY
12.1Mechanism of Action The mechanism of action underlying the beneficial effects of BiDil in the treatment of heart failure has not been established. Isosorbide dinitrate is a vasodilator affecting both arteries and veins. Its dilator properties result from the release of nitric oxide and the subsequent activation of guanylyl cyclase, and ultimate relaxation of vascular smooth muscle.
Several well-controlled clinical trials have used exercise testing to assess the anti-anginal efficacy of chronically-delivered nitrates. In the large majority of these trials, active agents were no more effective than placebo after 24 hours (or less) of continuous therapy. Attempts to overcome nitrate tolerance by dose escalation, even to doses far in excess of those used acutely, have consistently failed.
Only after nitrates have been absent from the body for several hours is response to nitrates restored. Hydralazine hydrochloride is a selective dilator of arterial smooth muscle. Animal data suggests that hydralazine may also mitigate tolerance to nitrates.
12.2Pharmacodynamics The basis for the beneficial clinical effects of BiDil is not known. In a small study of patients with chronic heart failure administered single doses of hydralazine 75 mg, isosorbide dinitrate 20 mg, and the combination, the combination elicited a statistically significant decrease in pulmonary capillary wedge pressure compared to hydralazine alone. The increase in cardiac output, renal blood flow and limb blood flow with the combination, however, was not greater than with hydralazine alone.
There is no study of hemodynamic effects following multiple dosing.
12.3Pharmacokinetics Absorption BiDil: Following a single 75-mg oral dose of hydralazine plus 40 mg of isosorbide dinitrate to 19 healthy adults, peak plasma concentrations of hydralazine (88 ng/mL/65 kg) and isosorbide dinitrate (76 ng/mL/65 kg) were reached in 1 hour. The half-lives were about 4 hours for hydralazine and about 2 hours for isosorbide dinitrate. Peak plasma concentrations of the two active metabolites, isosorbide-2-mononitrate and isosorbide-5-mononitrate, were 98 and 364 ng/mL/65 kg, respectively, at about 2 hours.
No information is currently available regarding the effect of food on the bioavailability of hydralazine or isosorbide dinitrate from BiDil tablets. Hydralazine hydrochloride: About 2/3 of a 50-mg dose of 14 C-hydralazine hydrochloride given in gelatin capsules was absorbed in hypertensive subjects. In patients with heart failure, mean absolute bioavailability of a single oral dose of hydralazine 75 mg varies from 10 to 26%, with the higher percentages in slow acetylators.
Administration of doses escalating from 75 mg to 1000 mg three times daily to congestive heart failure patients resulted in an up to 9-fold increase in the dose normalized AUC, indicating non-linear kinetics of hydralazine, probably reflecting saturable first pass metabolism. Isosorbide dinitrate: Absorption of isosorbide dinitrate from tablets after oral dosing is nearly complete. The average bioavailability of isosorbide dinitrate is about 25%, but is highly variable (10%-90%) because of first-pass metabolism, and increases progressively during chronic therapy.
Serum concentrations reach their maximum about one hour after ingestion. Distribution Hydralazine hydrochloride: After intravenous administration of hydralazine in a dose of 0.3 mg/kg, the steady-state volume of distribution in patients with congestive heart failure was
2.2L/kg. Isosorbide dinitrate: The volume of distribution of isosorbide dinitrate is 2 to 4 L/kg. About 28% of circulating isosorbide dinitrate is protein bound.
Under steady-state conditions, isosorbide dinitrate accumulates significantly in muscle (pectoral) and vein (saphenous) wall relative to simultaneous plasma concentrations. Metabolism Hydralazine is metabolized by acetylation, ring oxidation and conjugation with endogenous compounds including pyruvic acid… [Excerpted — this section continues on DailyMed.]
🧬 Mechanism of Action ▾
12.1Mechanism of Action The mechanism of action underlying the beneficial effects of BiDil in the treatment of heart failure has not been established. Isosorbide dinitrate is a vasodilator affecting both arteries and veins. Its dilator properties result from the release of nitric oxide and the subsequent activation of guanylyl cyclase, and ultimate relaxation of vascular smooth muscle.
Several well-controlled clinical trials have used exercise testing to assess the anti-anginal efficacy of chronically-delivered nitrates. In the large majority of these trials, active agents were no more effective than placebo after 24 hours (or less) of continuous therapy. Attempts to overcome nitrate tolerance by dose escalation, even to doses far in excess of those used acutely, have consistently failed.
Only after nitrates have been absent from the body for several hours is response to nitrates restored. Hydralazine hydrochloride is a selective dilator of arterial smooth muscle. Animal data suggests that hydralazine may also mitigate tolerance to nitrates.
📦 How Supplied / Storage and Handling ▾
16 HOW SUPPLIED/STORAGE AND HANDLING BiDil Tablets contain 20 mg of isosorbide dinitrate and 37.5 mg of hydralazine hydrochloride. They are biconvex, approximately 8 mm in diameter, scored, film-coated, orange tablets debossed "20" on one side over the score and " N " on the other side. NDC 24338-010-09: Bottles of 90 Store at 25°C (77°F), excursions permitted to 15-30°C (59-86°F). [See USP Controlled Room Temperature.] Keep bottles tightly closed.
Protect from light. Dispense in a light-resistant, tight container.
📋 Description ▾
11 DESCRIPTION BiDil is a fixed-dose combination of isosorbide dinitrate, a vasodilator with effects on both arteries and veins, and hydralazine hydrochloride, a predominantly arterial vasodilator. Isosorbide dinitrate is described chemically as 1,4:3,6-dianhydro-D-glucitol dinitrate and its structural formula is: Isosorbide dinitrate is a white to off-white, crystalline powder with the empirical formula C 6 H 8 N 2 O 8 and a molecular weight of 236.14. It is freely soluble in organic solvents such as alcohol, chloroform and ether, but is only sparingly soluble in water.
Hydralazine hydrochloride is described chemically as 1-hydrazinophthalazine monohydrochloride, and its structural formula is: Hydralazine hydrochloride is a white to off-white, crystalline powder with the empirical formula C 8 H 8 N 4 ∙HCl and a molecular weight of 196.64. It is soluble in water, slightly soluble in alcohol, and very slightly soluble in ether. Each BiDil Tablet for oral administration contains 20 mg of isosorbide dinitrate and 37.5 mg of hydralazine hydrochloride.
The inactive ingredients in BiDil tablets include: anhydrous lactose, microcrystalline cellulose, sodium starch glycolate, colloidal silicon dioxide, magnesium stearate, hypromellose, FD&C Yellow No. 6 aluminum lake, polyethylene glycol, titanium dioxide, polysorbate 80. structure1 structure2
💬 Information for Patients ▾
17 PATIENT COUNSELING INFORMATION Patients should be informed of possible side effects and advised to take the medication regularly and continuously as directed. Headache Inform patients that headaches often accompany treatment with BiDil, especially during initiation of treatment. Advise patients to consult a physician to adjust the dose of BiDil if headache continues with repeated dosing.
Hypotension Warn patients about lightheadedness on standing. Advise patients that inadequate fluid intake or excessive fluid loss from perspiration, diarrhea or vomiting may lead to an excessive fall in blood pressure and cause lightheadedness or even syncope. If syncope does occur, advise patients to discontinue BiDil and notify their prescribing physician as soon as possible.
Phosphodiesterase-5 Inhibitors Advise patients to inform their physicians if they are taking, or planning to take, sildenafil, vardenafil, or tadalafil. Bidil should not be taken concomitantly with phosphodiesterase-5 inhibitors. Worsening Ischemic Heart Disease Advise patients to inform their physicians of any worsening of symptoms of myocardial ischemia, especially those with hypertrophic cardiomyopathy.
Systemic Lupus Erythematosus-like Symptoms Advise patients if symptoms suggestive of systemic lupus erythematosus—such as arthralgia, fever, chest pain, prolonged malaise—occur to notify their prescribing physician. Peripheral Neuritis Advise patients if symptoms of peripheral neuritis—paresthesia, numbness, and tingling—occur to notify the prescribing physician. Manufactured for: Azurity Pharmaceuticals, Inc.
Woburn, MA 01801 USA Manufactured by: Lannett Company, Inc. Philadelphia, PA 19136 BiDil is a registered trademark of Azurity Pharmaceuticals, Inc. © 2025 All rights reserved BDL-PI-07 CIA75474J
🧬 Pharmacokinetics ▾
12.3Pharmacokinetics Absorption BiDil: Following a single 75-mg oral dose of hydralazine plus 40 mg of isosorbide dinitrate to 19 healthy adults, peak plasma concentrations of hydralazine (88 ng/mL/65 kg) and isosorbide dinitrate (76 ng/mL/65 kg) were reached in 1 hour. The half-lives were about 4 hours for hydralazine and about 2 hours for isosorbide dinitrate. Peak plasma concentrations of the two active metabolites, isosorbide-2-mononitrate and isosorbide-5-mononitrate, were 98 and 364 ng/mL/65 kg, respectively, at about 2 hours.
No information is currently available regarding the effect of food on the bioavailability of hydralazine or isosorbide dinitrate from BiDil tablets. Hydralazine hydrochloride: About 2/3 of a 50-mg dose of 14 C-hydralazine hydrochloride given in gelatin capsules was absorbed in hypertensive subjects. In patients with heart failure, mean absolute bioavailability of a single oral dose of hydralazine 75 mg varies from 10 to 26%, with the higher percentages in slow acetylators.
Administration of doses escalating from 75 mg to 1000 mg three times daily to congestive heart failure patients resulted in an up to 9-fold increase in the dose normalized AUC, indicating non-linear kinetics of hydralazine, probably reflecting saturable first pass metabolism. Isosorbide dinitrate: Absorption of isosorbide dinitrate from tablets after oral dosing is nearly complete. The average bioavailability of isosorbide dinitrate is about 25%, but is highly variable (10%-90%) because of first-pass metabolism, and increases progressively during chronic therapy.
Serum concentrations reach their maximum about one hour after ingestion. Distribution Hydralazine hydrochloride: After intravenous administration of hydralazine in a dose of 0.3 mg/kg, the steady-state volume of distribution in patients with congestive heart failure was
2.2L/kg. Isosorbide dinitrate: The volume of distribution of isosorbide dinitrate is 2 to 4 L/kg. About 28% of circulating isosorbide dinitrate is protein bound.
Under steady-state conditions, isosorbide dinitrate accumulates significantly in muscle (pectoral) and vein (saphenous) wall relative to simultaneous plasma concentrations. Metabolism Hydralazine is metabolized by acetylation, ring oxidation and conjugation with endogenous compounds including pyruvic acid. Acetylation occurs predominantly during the first-pass after oral administration which explains the dependence of the absolute bioavailability on the acetylator phenotype.
About 50% of patients are fast acetylators and have lower exposure. After oral administration of hydralazine, the major circulating metabolites are hydralazine pyruvate hydrazone and methyltriazolophthalazine. Hydralazine is the main pharmacologically active entity; hydralazine pyruvate hydrazone has only minimal hypotensive and tachycardic activity.
The pharmacological activity of methyltriazolophthalazine has not been determined. The major identified metabolite of hydralazine excreted in urine is acetylhydrazinophthalazinone. Isosorbide dinitrate undergoes extensive first-pass metabolism in the liver and is cleared at a rate of 2 to 4 L/minute with a serum half-life of about 1 hour.
Isosorbide dinitrate’s clearance is primarily by denitration to the 2-mononitrate (15 to 25%) and the 5-mononitrate (75 to 85%). Both metabolites have biological activity, especially the 5-mononitrate which has an overall half-life of about 5 hours. The 5-mononitrate is cleared by denitration to isosorbide, glucuronidation to the 5-mononitrate glucuronides, and by denitration/hydration to sorbitol.
The 2-mononitrate appears to participate in the same metabolic pathways with a half-life of about 2 hours. Elimination Hydralazine: Metabolism is the main route for the elimination of hydralazine. Negligible amounts of unchanged hydralazine are excreted in urine.
Isosorbide dinitrate: Most isosorbide dinitrate is eliminated renally as conjugated metabolites. Specific Populations No pharmacokinetic s… [Excerpted — this section continues on DailyMed.]
🧬 Pharmacodynamics ▾
12.2Pharmacodynamics The basis for the beneficial clinical effects of BiDil is not known. In a small study of patients with chronic heart failure administered single doses of hydralazine 75 mg, isosorbide dinitrate 20 mg, and the combination, the combination elicited a statistically significant decrease in pulmonary capillary wedge pressure compared to hydralazine alone. The increase in cardiac output, renal blood flow and limb blood flow with the combination, however, was not greater than with hydralazine alone.
There is no study of hemodynamic effects following multiple dosing.
🔬 Clinical Studies ▾
14 CLINICAL STUDIES BiDil or a combination of isosorbide dinitrate and hydralazine hydrochloride was studied in two placebo-controlled clinical trials in 1,692 patients with mild to severe heart failure (mostly NYHA class II and III) and one active control trial (vs. enalapril) in 804 patients. The results of the trials follow: Placebo-controlled Study: In the multicenter trial V-HeFT I, the combination of hydralazine and isosorbide dinitrate 75 mg/40 mg 4 times daily (n=186) was compared to placebo (n=273) in men with impaired cardiac function and reduced exercise tolerance (primarily NYHA class II and III) and on therapy with digitalis glycosides and diuretics.
There was no overall significant difference in mortality between the two treatment groups. There was, however, a trend favoring hydralazine and isosorbide dinitrate, which on retrospective analysis, was attributable to an effect in blacks (n=128). Survival in white patients (n=324) was similar on placebo and the combination treatment.
Active-controlled Study: In a second study of mortality, V-HeFT II, the combination of hydralazine and isosorbide dinitrate 75 mg/40 mg 4 times daily was compared to enalapril in 804 men with impaired cardiac function and reduced exercise tolerance (NYHA class II and III), and on therapy with digitalis glycosides and diuretics. The combination of hydralazine and isosorbide dinitrate was inferior to enalapril overall, but retrospective analysis showed that the difference was observed in the white population (n=574); there was essentially no difference in the black population (n=215).
Based on these retrospective analyses suggesting an effect on survival in black patients, but showing little evidence of an effect in the white population, a third study was conducted among black patients with heart failure. Placebo-controlled Study: The A-HeFT trial evaluated BiDil vs. placebo among 1,050 self-identified black patients (over 95% NYHA class III) at 169 centers in the United States. All patients had stable symptomatic heart failure.
Patients were required to have LVEF ≤ 35% or left ventricular internal diastolic dimension > 2.9 cm/m 2 plus LVEF < 45%. Patients were maintained on stable background therapy and randomized to BiDil (n=518) or placebo (n=532). BiDil was initiated at 20 mg isosorbide dinitrate/37.5 mg hydralazine hydrochloride three times daily and titrated to a target dose of 40/75 mg three times daily or to the maximum tolerated dose.
Patients were treated for up to 18 months. The randomized population was 60% male, 1% NYHA class II, 95% NYHA class III and 4% NYHA class IV, with a mean age of 57 years, and was generally treated with standard treatments for heart failure including diuretics (94%, almost all loop diuretics), beta-blockers (87%), angiotensin converting enzyme inhibitors (ACE-I; 78%), angiotensin II receptor blockers (ARBs; 28%), either ACE-I or ARB (93%), digitalis glycosides (62%) and aldosterone antagonists (39%). The primary endpoint was a composite score consisting of all-cause mortality, first hospitalization for heart failure, and responses to the Minnesota Living with Heart Failure questionnaire.
The trial was terminated early, at a mean follow-up of 12 months, primarily because of a statistically significant 43% reduction in all-cause mortality in the BiDil-treated group (p=0.012; see Table 2 and Figure 1). The primary endpoint was also statistically in favor of BiDil (p ≤ 0.021). The BiDil-treated group also showed a 39% reduction in the risk of a first hospitalization for heart failure (p<0.001; see Table 2 and Figure 2) and had statistically significant improvement in response to the Minnesota Living with Heart Failure questionnaire, a self-report of the patient’s functional status, at most time points (see Figure 3).
Patients in both treatment groups had mean baseline questionnaire scores of 51 (out of a possible 105). Table 2. Results of A-HeFT (Intent-To-Treat Population) BiDil (N=518) Placebo (N=532) H… [Excerpted — this section continues on DailyMed.]
🧪 Nonclinical Toxicology ▾
13 NONCLINICAL TOXICOLOGY
13.1Carcinogenesis, Mutagenesis, Impairment of Fertility Hydralazine hydrochloride: An increased incidence of lung tumors (adenomas and adenocarcinomas) was observed in a lifetime study in Swiss albino mice given hydralazine hydrochloride continuously in their drinking water at a dosage of about 250 mg/kg per day (6 times the MRHD provided by BiDil on a body surface area basis). In a 2-year carcinogenicity study of rats given hydralazine hydrochloride by gavage at dose levels of 15, 30, and 60 mg/kg/day (up to 3 times the MRHD of BiDil on a body surface area basis), microscopic examination of the liver revealed a small, but statistically significant increase in benign neoplastic nodules in males (high-dosage) and females (both high and intermediate dosage groups).
Benign interstitial cell tumors of the testes were also significantly increased in the high-dose group. Hydralazine hydrochloride is mutagenic in bacterial systems, and is positive in rat and rabbit hepatocyte DNA repair studies in vitro . Additional in vivo and in vitro studies using lymphoma cells, germinal cells, fibroblasts from mice, bone marrow cells from Chinese hamsters and fibroblasts from human cell lines did not demonstrate any mutagenic or clastogenic potential for hydralazine hydrochloride.
Isosorbide dinitrate: No long-term animal studies have been performed to evaluate the mutagenic or carcinogenic potential of isosorbide dinitrate. A modified two-litter reproduction study among rats fed isosorbide dinitrate at 25 or 100 mg/kg/day (up to 9 times the Maximum Recommended Human Dose of BiDil on a body surface area basis) revealed no evidence of altered fertility or gestation.
📄 Carcinogenesis, Mutagenesis, Impairment of Fertility ▾
13.1Carcinogenesis, Mutagenesis, Impairment of Fertility Hydralazine hydrochloride: An increased incidence of lung tumors (adenomas and adenocarcinomas) was observed in a lifetime study in Swiss albino mice given hydralazine hydrochloride continuously in their drinking water at a dosage of about 250 mg/kg per day (6 times the MRHD provided by BiDil on a body surface area basis). In a 2-year carcinogenicity study of rats given hydralazine hydrochloride by gavage at dose levels of 15, 30, and 60 mg/kg/day (up to 3 times the MRHD of BiDil on a body surface area basis), microscopic examination of the liver revealed a small, but statistically significant increase in benign neoplastic nodules in males (high-dosage) and females (both high and intermediate dosage groups).
Benign interstitial cell tumors of the testes were also significantly increased in the high-dose group. Hydralazine hydrochloride is mutagenic in bacterial systems, and is positive in rat and rabbit hepatocyte DNA repair studies in vitro . Additional in vivo and in vitro studies using lymphoma cells, germinal cells, fibroblasts from mice, bone marrow cells from Chinese hamsters and fibroblasts from human cell lines did not demonstrate any mutagenic or clastogenic potential for hydralazine hydrochloride.
Isosorbide dinitrate: No long-term animal studies have been performed to evaluate the mutagenic or carcinogenic potential of isosorbide dinitrate. A modified two-litter reproduction study among rats fed isosorbide dinitrate at 25 or 100 mg/kg/day (up to 9 times the Maximum Recommended Human Dose of BiDil on a body surface area basis) revealed no evidence of altered fertility or gestation.
📄 Package Label / Principal Display Panel ▾
PRINCIPAL DISPLAY PANEL - 90 Tablet Bottle Label NDC 24338-010-09 90 tablets BiDil ® isosorbide dinitrate and hydralazine HCl tablets 20 mg/37.5 mg Store at room temperature 15°C - 30°C (59°F - 86°F) BDL-TL-09-01 Rev. 11/25 CIB71996C Rx only bidil-20mg