In a few patients hydralazine may produce a clinical picture simulating systemic lupus erythematosus including glomerulonephritis. In such patients hydralazine should be discontinued unless the benefit-to-risk determination requires continued antihypertensive therapy with this drug. Symptoms and signs usually regress when the drug is discontinued but residua have been detected many years later. Long-term treatment with steroids may be necessary. (See PRECAUTIONS, Laboratory Tests.)
There is currently no manufacturer warning information available for this drug.
Severe essential hypertension when the drug cannot be given orally or when there is an urgent need to lower blood pressure.
Hydralazine Hydrochloride Injection, USP is an antihypertensive available in a 1 mL vial for intravenous and intramuscular administration. Each milliliter of the sterile, nonpyrogenic colorless solution contains Hydralazine Hydrochloride USP, 20 mg, Propylene Glycol USP, 103.6 mg, and Water for Injection q.s. The pH of the solution is 3.4 – 4.4. pH may be adjusted with Hydrochloric Acid and/or Sodium Hydroxide. Hydralazine Hydrochloride is 1-Hydrazinophthalazine monohydrochloride, and its structural formula is:
structure
Molecular Formula C8H8N4HCl
Hydralazine Hydrochloride USP is a white to off-white, odorless crystalline powder. It is soluble in water, slightly soluble in alcohol, and very slightly soluble in ether. It melts at about 275°C, with decomposition, and has a molecular weight of 196.64.
