From the Guidelines
The oral dose of hydralazine for hypertension is 100-200 mg, taken 2 or 3 times a day. 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, hydralazine is a direct vasodilator that can be used to treat hypertension. The recommended dose is listed in the guideline as 100-200 mg, taken 2 or 3 times a day. Some key points to consider when using hydralazine include:
- It is associated with sodium and water retention and reflex tachycardia, so it is often used with a diuretic and beta blocker 1
- It can cause drug-induced lupus-like syndrome at higher doses 1
- The dose may need to be adjusted based on the patient's response to the medication and their individual characteristics, such as renal function and age. It's also important to monitor blood pressure regularly when taking hydralazine, as dosage adjustments may be necessary. Common side effects include headache, palpitations, and tachycardia. Long-term use requires monitoring for potential development of drug-induced lupus-like syndrome, particularly at higher doses. Hydralazine is often used in combination with a beta-blocker to counteract reflex tachycardia and a diuretic to prevent fluid retention.
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. For maintenance, adjust dosage to the lowest effective levels. In a few resistant patients, up to 300 mg of hydrALAZINE hydrochloride tablets daily may be required for a significant antihypertensive effect. The oral dose of hydralazine for hypertension is:
- Initial dose: 10 mg four times daily for the first 2 to 4 days
- First week: 25 mg four times daily
- Subsequent weeks: 50 mg four times daily
- Maximum dose: up to 300 mg daily for resistant patients 2
From the Research
Oral Dose of Hydralazine for Hypertension
- The oral dose of hydralazine for hypertension is not explicitly stated in the provided studies as a standard or universally recommended dose.
- However, according to the study 3, the effect on blood pressure of giving hydralazine orally, 300 mg per day divided into 2,3, and 4 doses, was studied in 4 hypertensive patients, indicating that 300 mg per day is a dose that has been used in clinical settings.
- Another study 4 examined the effect of oral dose size on hydralazine kinetics and vasodepressor response, suggesting that the proportion of hydralazine that reaches systemic circulation increases with the dose size.
- The study 5 investigated the kinetics of hydralazine elimination and found that the acetylation of hydralazine in humans is a capacity-limited process, which may affect the dosage required for therapeutic effect.
Dosage Considerations
- The dosage of hydralazine may need to be carefully titrated on an individual basis due to the hypersensitivity of patients to depressor agents, as mentioned in the study 6.
- The study 7 discusses the management of hypertensive emergencies, including the use of intravenous hydralazine, but does not provide specific oral dosage recommendations for hypertension management.
- It is essential to consider the individual patient's response to hydralazine and adjust the dosage accordingly to achieve the desired therapeutic effect while minimizing potential side effects, as indicated by the studies 3 and 4.