Can hydralazine be administered four times daily?

From the Guidelines

Hydralazine can be administered two or three times daily, but there is no clear evidence to support a four-times-daily dosing schedule. According to 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, the usual dose range for hydralazine is 100-200 mg, with a daily frequency of 2 or 3 times.

Key Considerations

• The dosing schedule for hydralazine may vary depending on the individual patient's needs and response to treatment.
• Hydralazine is often used in combination with other medications, such as diuretics and beta blockers, to achieve optimal blood pressure control.
• The medication works by directly relaxing the smooth muscle in arterial walls, causing vasodilation and reducing blood pressure.

Administration and Monitoring

• When starting hydralazine, doctors usually begin with a lower dose and gradually increase it to minimize side effects like headache, dizziness, and reflex tachycardia.
• It's essential to take hydralazine at evenly spaced intervals throughout the day to maintain consistent blood pressure control.
• Patients should be monitored regularly for signs of adverse effects, such as sodium and water retention, reflex tachycardia, and drug-induced lupus-like syndrome.

Evidence-Based Recommendations

• The most recent and highest-quality study, the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline 1, provides evidence-based recommendations for the use of hydralazine in the management of hypertension.
• Other studies, such as the 2008 ESC guidelines for the diagnosis and treatment of acute and chronic heart failure 2 and the 2013 ACCF/AHA guideline for the management of heart failure 3, also provide guidance on the use of hydralazine in specific patient populations.

From the FDA Drug Label

The usual recommended oral starting dosage is 0.75 mg/kg of body weight daily in four divided doses. The answer is yes, hydralazine can be administered four times daily, as the recommended oral starting dosage is given in four divided doses 4.

• The dosage may be increased gradually over the next 3 to 4 weeks to a maximum of 7.5 mg/kg or 200 mg daily.
• This administration schedule is specifically mentioned for pediatric patients, but it implies that four times daily administration is acceptable.

From the Research

Administration Frequency of Hydralazine

• The study 5 compared the efficacy and tolerability of slow-release hydralazine administered once daily with conventional hydralazine given two to four times a day, and found that blood pressure control achieved with multiple doses of conventional hydralazine was maintained with slow-release hydralazine.
• Another study 6 assessed the effects of hydralazine formulation and dose interval in 20 patients with hypertension, and concluded that there is no need to administer hydralazine more than twice daily.
• The evidence suggests that hydralazine can be administered less frequently than four times daily, with twice daily or even once daily administration being sufficient in some cases 5, 6.
• However, the optimal administration frequency may depend on individual patient factors, such as the presence of side effects or the specific formulation of hydralazine being used.
• There is no direct evidence to support the administration of hydralazine four times daily, and the available studies suggest that less frequent administration may be effective and sufficient 5, 6.