Congestive heart failure:
- The initial dose for treating heart failure is 10 to 25 mg orally 3 to 4 times daily.
- The usual dose is 225 to 300 mg daily in 3 to 4 divided doses.
For pediatric hypertensive emergencies, the dose is 0.5 mg/Kg IV every 4 hours.
DRUG CLASS AND MECHANISM: Hydralazine (Apresoline) is an antihypertensive medication used to treat high blood pressure. It is a peripheral arterial vasodilator and causes relaxation of blood vessels which carry blood away from the heart and towards the organs and tissues. The exact mechanism of how hydralazine causes arterial smooth muscle relaxation is not yet understood. Hydrazine affects calcium movement within blood vessels. Calcium is required for muscle contraction and therefore disturbances in calcium movement may cause smooth muscle relaxation in the blood vessels. Hydralazine is selective for arterioles (small arteries), and the overall effects of treatment include a decrease in arterial blood pressure, and peripheral vascular resistance.
In addition to treating high blood pressure, hydralazine has shown to be beneficial for the treatment of congestive heart failure (CHF). Although ACE inhibitors are preferred for the treatment of CHF, hydralazine in combination with isosorbide dinitrate (Isordil, Isordil Titradose, Dilatrate-SR) is an alternative for patients who cannot tolerate ACE inhibitors.
Hydralazine was approved by the US Food and Drug Administration (FDA) in 1952 as an antihypertensive agent. It is commonly used for the treatment of hypertension in pregnancy. Parenteral or injectable hydralazine is used to treat hypertensive emergencies (severally high blood pressure) during pregnancy.
Medically reviewed by Eni Williams, PharmD, PhD
REFERENCE: FDA Prescribing Information.
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