What is the recommended dose of Hydralazine (Apresoline) for hypertension?

From the Guidelines

Hydralazine should be dosed at 10 mg via slow IV infusion, with a maximum initial dose of 20 mg, and repeated every 4-6 hours as needed for the treatment of hypertensive emergencies. The dosing of hydralazine is crucial in managing hypertensive emergencies, and the recommended dose is based on the most recent guidelines 1. Key points to consider when dosing hydralazine include:

• Initial dose: 10 mg via slow IV infusion, with a maximum initial dose of 20 mg
• Frequency: every 4-6 hours as needed
• Monitoring: blood pressure should be closely monitored, and the dose adjusted accordingly
• Side effects: patients should be monitored for side effects including headache, dizziness, tachycardia, and fluid retention The use of hydralazine in hypertensive emergencies is supported by 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. It is essential to note that hydralazine works by directly relaxing vascular smooth muscle, primarily affecting arterioles rather than veins, which leads to decreased peripheral resistance and blood pressure reduction. In addition to the IV dosing, hydralazine can also be given orally, with typical doses ranging from 100-200 mg per day, divided into 2-3 doses, for the treatment of hypertension 1. However, the IV dosing is preferred in hypertensive emergencies due to its rapid onset of action. Overall, the dosing of hydralazine should be individualized and based on the patient's response to treatment, with close monitoring of blood pressure and adjustment of the dose as needed.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Initiate therapy in gradually increasing dosages; adjust according to individual response. Start with 10 mg four times daily for the first 2 to 4 days, increase to 25 mg four times daily for the balance of the first week. For the second and subsequent weeks, increase dosage to 50 mg four times daily. The incidence of toxic reactions, particularly the L. E. cell syndrome, is high in the group of patients receiving large doses of hydrALAZINE hydrochloride tablets. In a few resistant patients, up to 300 mg of hydrALAZINE hydrochloride tablets daily may be required for a significant antihypertensive effect.

The recommended initial dose of hydralazine is 10 mg four times daily for the first 2 to 4 days, then increased to 25 mg four times daily for the balance of the first week, and finally to 50 mg four times daily for the second and subsequent weeks. The maximum dose is up to 300 mg daily for resistant patients, but it is recommended to use the lowest effective levels and consider combining therapy with other medications to minimize the dose of hydralazine 2.

From the Research

Hydralazine Dose

• The optimal dose of hydralazine is not explicitly stated in the provided studies, but the general approach to antihypertensive therapy is to start with a low dose and gradually increase it under close blood pressure control 3.
• In the treatment of heart failure with reduced ejection fraction, hydralazine is often used in combination with nitrates, and the dose is not specified in the studies 4, 5.
• The studies focus on the benefits of combining hydralazine with nitrates in patients with heart failure, particularly in African American patients 4, 5.
• The hemodynamic effects of hydralazine and nitrates are additive, resulting in improved cardiac function and reduced filling pressures 6, 7.
• The dose of hydralazine may need to be adjusted based on individual patient response and tolerance, as well as the presence of other medical conditions, such as coronary heart disease 3.

Key Findings

• Hydralazine is often used in combination with nitrates to treat heart failure with reduced ejection fraction 4, 5.
• The combination of hydralazine and nitrates has been shown to improve survival and reduce mortality in patients with heart failure 4, 5.
• The hemodynamic effects of hydralazine and nitrates are complementary, with hydralazine reducing afterload and nitrates reducing preload 6, 7.
• The optimal dosing strategy for hydralazine is not explicitly stated in the studies, but it is generally recommended to start with a low dose and gradually increase it under close blood pressure control 3.