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Isosorbide dinitrate/hydralazine is a fixed dose combination drug treatment specifically indicated for African Americans with congestive heart failure. It is a combination of hydralazine (an antihypertensive) and isosorbide dinitrate (a vasodilator). It is the first race-based prescription drug in the United States. The combination preparation is marketed in the United States by Nitromed under the trade name BiDil.

Originally rejected by the Food and Drug Administration (FDA) in 1997, the combination preparation was approved by the FDA in June 2005 for the use of African Americans. It was already known that African American individuals with congestive heart failure (CHF) respond less effectively to conventional CHF treatments (particularly ACE inhibitors) than Caucasians.^[1] The study by Taylor et al., based on which the FDA approved the medication demonstrated that isosorbide dinitrate with hydralazine reduced mortality by 43%, reduced hospitalizations by 39%, and quality of life markers in African-American patients with CHF.^[2] After approval, a deeper look at the research showed that clinical trials of Bidil involved only self-described African Americans, and that the drug was not useful for all blacks and very useful for some whites.

Because the combination preparation comprises two generically-available drugs, widely available at a small fraction of the cost, BiDil is considered a marketing innovation, rather than a medical one; however, the 43% mortality benefit remains a notable benefit. The combination intended to reduce the "pill burden" for patients, which improves compliance and therefore the medical outcome. Moreover, the FDA issued a letter in May, 2006 stating that there is no bioequivalent, generic substitute to BiDil. With the 2005 FDA approval and with the issuance of a patent, BiDil is unique and no alternative therapy exists for the target patient population. In 2006, the Heart Failure Society of America included the use of the fixed dose combination of isosorbide dinitrate/hydralazine as the standard of care in the treatment of heart failure in blacks. In 2007, at the American College of Cardiology's annual scientific meeting in New Orleans, data was presented demonstrating a pharmacokenetic distinction between the fixed dose combination and the component agents that may account for the superior clinical benefit in mortality shown in the African American Heart Failure Trial.

There is, however, concern that the approval of this drug may be used to promote racist thinking, especially because the study data used to approve the medication only included self described African American participants and no other racial groups. BiDil could potentially be beneficial to all patients suffering from heart failure.^[3]

See also

• Pharmacogenetics
• Pharmacogenomics

References

External links

• Official website
• FDA approval process page
• WNYC Radiolab audio story about racial issues surrounding Bidil
• FDA approval press release
• Scientific American article criticizing approval of Bidil
  • Scientific American article response by manufacturer to previous article's criticism
  • Response for FDA's Robert Temple to Scientific American article