From the Guidelines
The recommended dose of hydralazine for treating hypertension is 100-200 mg daily, divided into 2 or 3 doses, as indicated by the most recent guidelines 1. When considering the treatment of hypertension with hydralazine, it's crucial to understand that this medication is a direct vasodilator, which means it works by relaxing the smooth muscle in blood vessels, thereby reducing blood pressure.
- The dose range of 100-200 mg daily is recommended, with the medication typically administered in 2 or 3 doses throughout the day.
- It's essential to note that hydralazine can cause sodium and water retention, as well as reflex tachycardia, and therefore, it is often used in conjunction with a diuretic and a beta-blocker to mitigate these side effects 1.
- Additionally, hydralazine has been associated with drug-induced lupus-like syndrome at higher doses, emphasizing the need for careful monitoring and dose adjustment based on patient response and tolerance.
- The guidelines also suggest that dosages may vary from those listed in the FDA-approved labeling, and adjustments should be made based on the patient's blood pressure response and tolerance to the medication 1.
- An older study 1 mentions dose up-titration after 2–4 weeks, aiming for an evidence-based target dose or the maximum tolerated dose, but the most recent and highest quality guidelines 1 provide the dose range of 100-200 mg daily, divided into 2 or 3 doses, as the recommended approach for treating hypertension with hydralazine.
From the FDA Drug Label
The usual recommended oral starting dosage is 0.75 mg/kg of body weight daily in four divided doses. Dosage may be increased gradually over the next 3 to 4 weeks to a maximum of 7. 5 mg/kg or 200 mg daily. The recommended dose of hydralazine for treating hypertension is 0.75 mg/kg of body weight daily in four divided doses, with a maximum dose of 7.5 mg/kg or 200 mg daily. The frequency is four divided doses per day. 2
From the Research
Hydralazine Dosage and Frequency
The recommended dose and frequency of hydralazine for treating hypertension vary depending on the formulation and patient response.
- The typical dose range is between 75-300 mg per day, divided into two to four doses 3.
- A study comparing conventional and slow-release hydralazine found that once-daily administration of slow-release hydralazine was effective in maintaining blood pressure control, with no significant difference in efficacy between once-daily and twice-daily administration 4.
- Another study found that the maximum antihypertensive response to hydralazine was 9.4 mm Hg, with a daily dose of 0.87 mg/kg for slow acetylators and 1.68 mg/kg for fast acetylators eliciting 50% of the maximum response 3.
- In terms of specific dosing regimens, one study used hydralazine 100 mg twice daily, while another used 25-100 mg twice daily in combination with propranolol 5, 6.
Factors Affecting Dosage
Several factors can affect the dosage and frequency of hydralazine, including:
- Acetylator status: Slow acetylators may require lower doses than fast acetylators 3.
- Concomitant medication: The use of beta-blockers, diuretics, or other antihypertensive agents may affect the dosage and frequency of hydralazine 3, 6.
- Patient response: The dosage and frequency of hydralazine may need to be adjusted based on individual patient response and blood pressure control 4, 3.
Administration Regimens
Different administration regimens have been studied, including: