From the Guidelines
A single dose of hydralazine for prn use in blood pressure management is 10 mg via slow IV infusion, with a maximum initial dose of 20 mg, as needed, based on the most recent and highest quality evidence from the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline 1.
Key Considerations
- The dose can be repeated every 4-6 hours as needed, with blood pressure monitoring to assess response.
- For elderly patients or those with renal impairment, starting at the lower end of the dosing range (10 mg) is recommended.
- Hydralazine works as a direct arterial vasodilator, relaxing vascular smooth muscle and reducing peripheral resistance, which effectively lowers blood pressure.
Administration and Monitoring
- When administering hydralazine, blood pressure should be monitored frequently, typically every 5-15 minutes after IV administration.
- Common side effects include reflex tachycardia, headache, flushing, and dizziness.
- Hydralazine should be used cautiously in patients with coronary artery disease as the reflex tachycardia may worsen cardiac ischemia, as noted in the guideline 1 and executive summary 1.
Evidence Basis
- The recommended dose is based on the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1, which provides the most recent and highest quality evidence for hydralazine dosing.
- The guideline emphasizes the importance of careful monitoring and individualized dosing to minimize the risk of adverse effects and optimize blood pressure control.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION Initiate therapy in gradually increasing dosages; adjust according to individual response. The FDA drug label does not answer the question.
From the Research
Single Dose of Hydralazine for PRN Use
- A single dose of hydralazine for PRN (pro re nata) use can vary depending on the specific clinical context and patient population.
- According to a study published in 2010 2, the typical dose of intravenous hydralazine for PRN use is 10-20 mg per dose.
- Another study from 1994 3 used a dose of 5 mg of intravenous bolus hydralazine, repeated every 15 minutes as needed, to control severe hypertension in pre-eclampsia.
- It is essential to note that the dosage and administration of hydralazine should be individualized and guided by clinical judgment, taking into account the patient's specific condition, response to treatment, and potential side effects.
Blood Pressure Management
- Hydralazine is commonly used for the treatment of acute hypertension in hospitalized patients, often in conjunction with other antihypertensive agents 4, 2.
- The goal of PRN use of hydralazine is to rapidly lower blood pressure and prevent potential complications, such as organ damage or cardiovascular events.
- However, the optimal dosing strategy and treatment thresholds for PRN use of hydralazine are not well established and may vary depending on the specific clinical context and patient population 4, 5.