What is the recommended dosing and monitoring for hydralazine (apresoline) in treating hypertension?

From the Guidelines

For treating hypertension with hydralazine (Apresoline), the recommended starting dose is 10 mg orally four times daily, which can be gradually increased to 25-50 mg four times daily as needed, with a maximum daily dose not exceeding 300 mg, as per the guidelines 1. The dosing and monitoring of hydralazine should be individualized, taking into account the patient's response to the medication and potential side effects. Some key points to consider when using hydralazine include:

• Blood pressure monitoring should be performed regularly, initially within 1-2 hours after dosing to assess immediate effects, then at each follow-up visit to evaluate overall control.
• Patients should be monitored for common side effects including headache, tachycardia, fluid retention, and lupus-like syndrome.
• Laboratory monitoring should include complete blood count, antinuclear antibody testing, and renal function tests at baseline and periodically during treatment, especially with long-term use or doses exceeding 200 mg daily.
• Hydralazine works as a direct arterial vasodilator, relaxing vascular smooth muscle to reduce peripheral resistance.
• It's often combined with a beta-blocker to counteract reflex tachycardia and a diuretic to manage fluid retention.
• Hydralazine is particularly useful in pregnancy-related hypertension and in patients with renal impairment, but should be used cautiously in patients with coronary artery disease due to its potential to cause reflex sympathetic stimulation 1. In cases of resistant hypertension, hydralazine may be added as a fourth or fifth agent, in combination with other medications such as nitrates, diuretics, and beta-blockers, to achieve optimal blood pressure control 1.

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. The recommended dosing for hydralazine (Apresoline) in treating hypertension is:

• Initial dose: 10 mg four times daily for the first 2 to 4 days
• First week: 25 mg four times daily
• Second and subsequent weeks: 50 mg four times daily
• Maintenance: adjust dosage to the lowest effective levels Monitoring should be done to ensure the lowest possible therapeutic dose, especially when combining therapy with other drugs 2.

From the Research

Hydralazine Side Effects and Monitoring

• Hydralazine has been associated with various side effects, including autoimmune diseases such as hydralazine-induced antineutrophil cytoplasmic antibody-associated vasculitis (ANCA-vasculitis) and lupus-like syndrome characterized by multiorgan involvement and complex clinical manifestations 3.
• Other reported side effects of hydralazine include reflex tachycardia, hemolytic anemia, vasculitis, glomerulonephritis, and a lupus-like syndrome 4.
• Hydralazine-induced vasculitis is a rare but serious side effect that can cause worsening kidney function, hematuria, and proteinuria 5.

Recommended Dosing and Monitoring

• There is insufficient evidence to conclude on the effects of hydralazine versus placebo on mortality, morbidity, withdrawals due to adverse effects, serious adverse events, or systolic and diastolic blood pressure 4.
• Hydralazine may reduce blood pressure when compared to placebo in patients with primary hypertension, however this data is based on before and after studies, not RCTs 4.
• The safety of hydralazine has been demonstrated in patients with eclampsia and preeclampsia, and it is widely used in the treatment of hypertension in these patients 6.
• Monitoring for side effects such as reflex tachycardia, hemolytic anemia, vasculitis, glomerulonephritis, and lupus-like syndrome is essential when using hydralazine to treat hypertension 3, 4, 5.

Alternative Antihypertensive Drugs

• Other antihypertensive drugs such as beta-blockers, diuretics, angiotensin converting enzyme inhibitors, angiotensin II receptor antagonists, and calcium channel blockers may be considered as alternative treatments for hypertension 7.
• The choice of antihypertensive drug depends on the individual patient's condition and the presence of any comorbidities or contraindications 7.