Hydralazine is NOT Hydrazine: Critical Distinction
Hydralazine is an antihypertensive medication used to treat high blood pressure and heart failure, while hydrazine is a toxic industrial chemical and potential carcinogen with no established role in treating hypertension or cancer in humans. These are completely different compounds that should not be confused.
Hydralazine (The Medication)
Primary Cardiovascular Uses
Hydralazine is a direct arterial vasodilator approved for treating hypertension and heart failure, particularly in specific patient populations. 1
In heart failure with reduced ejection fraction (HFrEF): Hydralazine combined with isosorbide dinitrate is a Class I recommendation for self-described Black patients with persistent NYHA class III-IV symptoms on background therapy with ACE inhibitors/ARBs and beta-blockers 1
In resistant hypertension: The American College of Cardiology recommends hydralazine as a fifth-line agent after other medications have failed to achieve blood pressure control 2
Must be combined with beta-blockers and diuretics due to reflex tachycardia and sodium/water retention that occur with hydralazine monotherapy 1, 2
Key Clinical Considerations
Keep total daily doses below 150 mg to avoid drug-induced lupus-like syndrome 2
Hydralazine without nitrates lacks randomized trial evidence for efficacy in heart failure 1
Associated with frequent adverse reactions including headache and gastrointestinal complaints at target doses 1
Hydrazine (The Chemical)
Cancer Treatment Claims
Hydrazine sulfate has been investigated as an anticachexia agent in cancer but lacks convincing evidence of efficacy and is classified as a possible human carcinogen. 3, 4
Small studies showed no objective tumor responses in most patients, with only brief subjective benefit in a minority 5
One uncontrolled study claimed symptomatic benefits in advanced cancer patients, but this lacks validation in rigorous trials 6
The U.S. EPA, Department of Health and Human Services, and International Agency for Research on Cancer classify hydrazines as possible cancer-causing environmental contaminants 4
Safety Concerns
Hydrazine is a metabolite of hydralazine and has demonstrated carcinogenicity in rats and mice 7
Causes adverse systemic health effects through environmental exposure via contaminated water, air, or dust 4
Found at hazardous waste sites and designated as an environmental contaminant 4
Bottom Line
Hydralazine is a legitimate cardiovascular medication with specific guideline-directed indications, while hydrazine is a toxic chemical with no established therapeutic role. If the question concerns treating hypertension or heart failure, hydralazine is the appropriate agent when used according to guideline recommendations 1. If the question concerns cancer treatment, hydrazine sulfate lacks evidence of benefit and carries significant safety concerns 5, 4.