hydralazine/isosorbide dinitrate vs sildenafil
Side-by-side comparison of hydralazine/isosorbide dinitrate and sildenafil. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
major Known Drug Interaction
7 DRUG INTERACTIONS 7.1 Phosphodiesterase 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.
Recommendation: Do not take these two medications together.
Viagra, Revatio
BiDil is a medicine that combines two drugs to help treat heart failure. It contains isosorbide dinitrate and hydralazine hydrochloride, which work together to widen blood vessels.
Sildenafil is a medicine used to treat erectile dysfunction (ED) in men. It helps increase blood flow to the penis to get and keep an erection.
BiDil is used to treat heart failure in self-identified Black patients. It is used along with other standard heart failure treatments. BiDil can help you live longer, spend less time in the hospital because of heart failure, and feel better overall.
Sildenafil is used to treat erectile dysfunction (ED), also known as impotence, in men. ED is when you cannot get or keep an erection firm enough for sex. Sildenafil helps by increasing blood flow to the penis when you are sexually stimulated.
BiDil contains two medicines that work in different ways to widen your blood vessels. Isosorbide dinitrate widens both arteries and veins. Hydralazine hydrochloride mainly widens arteries.
Sildenafil belongs to a class of drugs called PDE5 inhibitors. It works by relaxing the muscles and increasing blood flow to the penis during sexual stimulation. This helps you get and keep an erection.
- • Headache
- • Dizziness
- • Headache
- • Flushing (redness of the skin)
- • Upset stomach
- • Abnormal vision (blurred vision, changes in color vision)
- • Nasal congestion (stuffy nose)
- Long-term kidney disease 2,819
- Sudden kidney damage 2,616
- Kidney failure 2,097
- Final stage of kidney failure 1,585
- Tiredness 1,541
- Shortness of breath 7,729
- Headache 5,655
- Diarrhea 4,447
- Nausea 3,984
- Death 3,872
BiDil can cause low blood pressure, especially when you stand up. This is more likely if you are dehydrated or have low salt levels. Hydralazine hydrochloride, one of the medicines in BiDil, can cause a lupus-like syndrome. If you have symptoms, your doctor may tell you to stop taking BiDil. BiDil can also worsen chest pain, especially if you have certain heart conditions.
You should not take sildenafil if you are taking nitrates for chest pain, as this can cause a dangerous drop in blood pressure. If you have an erection that lasts longer than 4 hours, get medical help right away. Stop taking sildenafil and seek medical attention if you have a sudden loss of vision or hearing.
It is not known if BiDil is safe to use during pregnancy. Talk to your doctor if you are pregnant or plan to become pregnant. It is also not known if BiDil passes into breast milk. Talk to your doctor about the best way to feed your baby if you are taking BiDil.
Sildenafil is not for use in women. It is not known if sildenafil can harm an unborn baby or pass into breast milk.
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How to Read This hydralazine/isosorbide dinitrate vs sildenafil Comparison
hydralazine/isosorbide dinitrate is classified in the Vasodilator / Nitrate Combination drug class, while sildenafil sits within the PDE5 Inhibitor class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, hydralazine/isosorbide dinitrate has 10,658 submissions while sildenafil has 25,687. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known major interaction flagged in FDA labeling, attributed to both drugs work to relax blood vessels, and taking them together can cause your blood pressure to drop to a dangerously low level.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between hydralazine/isosorbide dinitrate and sildenafil - always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.