What Are Hydralazine and Isosorbide Dinitrate (BiDil)?

There are numerous classes of drugs approved to treat systolic heart failure (HF). Isosorbide dinitrate and hydralazine, known by the brand name BiDil®, is the only heart failure medication with a specific indication for African Americans. This ethnic group is more likely to develop heart failure at a younger age than people of other ethnicities. They may also be more likely to be hospitalized or to die from HF.1

The treatment goal of BiDil is to reduce symptoms and the risk of death in self-described African Americans who are symptomatic despite being treated with ARNI/ACE inhibitor/, ARB's, beta-blockers and aldosterone antagonists. It can also be used in any patient with systolic heart failure who cannot tolerate ARNI/ACE inhibitors/ARBs.2

What are the ingredients in isosorbide dinitrate and hydralazine hydrochloride?

BiDil is a combination of isosorbide dinitrate, a nitrate vasodilator, and hydralazine, an arteriolar vasodilator.2

How do isosorbide dinitrate and hydralazine hydrochloride work?

The mechanism of action of isosorbide dinitrate and hydralazine in the treatment of heart failure has not been well established. Isosorbide dinitrate is a vasodilator affecting both arteries and veins. Its dilator properties are due to the release of nitric oxide and the subsequent activation of the enzyme guanylyl cyclase, which results in the relaxation of vascular smooth muscle.2 By relaxing the blood vessels, it is easier for the heart to pump forward. Hydralazine works on the smooth muscle of the arteries to cause vasodilation

What are the possible side effects of isosorbide dinitrate and hydralazine hydrochloride?

Any medication has possible adverse effects, and it’s important to be aware of the potential side effects when a patient starts a drug. Headaches and dizziness are the most common side effects of isosorbide dinitrate and hydralazine.1-2 They often occur when starting treatment and may become less frequent and less intense over time. If headaches do not subside, speak with your healthcare team about the need for a dosage adjustment.2

Make sure to drink enough fluids. Drinking less or losing fluids because of diarrhea, sweating, or vomiting can cause a drop in blood pressure, resulting in possible lightheadedness, or fainting. In general, it is important to take all medications as prescribed, but, if you faint, stop taking isosorbide dinitrate and hydralazine and call your healthcare team immediately.2

These are not all the possible side effects of BiDil. Patients should talk to their doctor about what to expect with treatment with BiDil.

Other side effects can include achy/swollen joints, unexplained fever, skin rash, chest pain, prolonged weakness, or fatigue (even when rested), Although less common, make a note of all symptoms when they occur and share the information at your next medical visit. Some people experience a rapid heartbeat that could lead to or aggravate chest pain or numbness or tingling in the hands or feet. Make sure to also share these symptoms.2

Things to know about isosorbide dinitrate and hydralazine hydrochloride

The US Food and Drug Administration (FDA) approved isosorbide dinitrate and hydralazine hydrochloride for use by self-identified African American patients in addition to routine HF medicines.1 When added to current standard HF drugs, isosorbide dinitrate and hydralazine hydrochloride reduced the risk of dying by 43% during clinical trials.1

People who are allergic to organic nitrates should not take isosorbide dinitrate and hydralazine. Bidil should not be taken with PDE-5 inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil or those taking soluble guanylate cyclase (sGC) stimulator riociguat as it can cause a life-threatening reaction.2

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Written by: Linda Minton | Last reviewed: March 2021