BiDil®

In July 2005, NitroMed introduced a prescription medicine named BiDil® (isosorbide dinitrate and hydralazine hydrochloride) to the market. During previous years, BiDil underwent a carefully controlled clinical study referred to as A-HeFT (The African American Heart Failure Trial). A-HeFT demonstrated the drug's effectiveness in improving symptoms in African American patients, when taken as an add-on to their standard heart failure medicines. BiDil was also shown to significantly improve survival and decrease time to first hospitalization for heart failure, compared to patients treated with standard therapy alone.  Based on this clinical evidence, BiDil was approved by the U.S. Food and Drug Administration (FDA) in June 2005.   

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.  There is little experience in patients with NYHA class IV heart failure.  Most patients in the clinical trial supporting effectiveness (A-HeFT) received a loop diuretic, an angiotensin converting enzyme inhibitor or an angiotensin II receptor blocker, and a beta blocker, and many also received a cardiac glycoside or an aldosterone antagonist. 

What is BiDil?

BiDil is a fixed-dose combination of hydralazine hydrochloride and isosorbide dinitrate (ISDN).  Hydralazine is an arterial vasodilator; it relaxes the arteries so the heart doesn’t have to work as hard to push blood through them.  Isosorbide dinitrate is also a vasodilator, with effects on both  the veins and the arteries.   ISDN releases nitric oxide at the blood vessel wall, but its effect wears off rapidly 1.  Hydralazine is thought to prevent the loss of ISDN’s effect 2, however the exact mechanism of how the two drugs work together is not fully understood.

1. Preik M, Kelm M, Feelisch M, Strauer BE.  Impaired effectiveness of nitric oxide-donors in resistance arteries of patients with arterial hypertension. J Hypertens. 1996;14:903-8.
2. Munzel T, Kurz S, Rajagopalan S, et al. Hydralazine prevents nitroglycerin tolerance by inhibiting activation of a membrane-bound NADH oxidase. A new action for an old drug. J Clin Invest 1996;98:1465-70.