From the Guidelines
Hydralazine is a direct-acting vasodilator medication primarily used to treat high blood pressure and heart failure, with a typical starting dose of 10 mg via slow IV infusion for hypertensive emergencies, and 100-200 mg orally 2-3 times daily for chronic hypertension, with careful monitoring for side effects and potential interactions 1, 2.
Key Points
- Hydralazine works by relaxing the smooth muscle in blood vessel walls, causing them to widen and reduce blood pressure.
- The medication is used to treat high blood pressure and heart failure, and is often prescribed in combination with nitrates to reduce cardiac workload and improve heart function.
- Common side effects include headache, dizziness, flushing, palpitations, and nasal congestion, while more serious concerns include a lupus-like syndrome with long-term use, particularly at higher doses and in slow acetylators (especially women) 3.
- Hydralazine should be used cautiously in patients with coronary artery disease as it may cause reflex tachycardia, and is considered relatively safe during breastfeeding, but should be used with caution in pregnancy 4.
Dosage and Administration
- For hypertensive emergencies, the typical starting dose is 10 mg via slow IV infusion, with repeat doses every 4-6 hours as needed 1.
- For chronic hypertension, the typical starting dose is 100-200 mg orally 2-3 times daily, with gradual increases as needed and careful monitoring for side effects and potential interactions 3.
Monitoring and Precautions
- Regular monitoring of blood pressure and heart rate is essential when using this medication to ensure proper dosing and effectiveness.
- Patients should be monitored for symptoms like joint pain, fever, and rash, and hydralazine should be used with caution in patients with a history of lupus or other autoimmune disorders 4.
From the Research
Use of Hydralazine (Apresoline)
- Hydralazine is a direct-acting vasodilator used for the treatment of hypertension 5
- It is commonly administered intravenously (IV) or orally to lower blood pressure in patients with severe hypertension 6, 7
- IV hydralazine has been shown to lead to a significant drop in blood pressure, with a reduction of 13-18 mmHg in mean arterial pressure (MAP) and systolic blood pressure (SBP) compared to no treatment 6
- Oral hydralazine is also effective in lowering blood pressure, although the reduction in blood pressure may be less pronounced compared to IV administration 6, 7
- Hydralazine is considered a first-line medication for the management of acute-onset, severe hypertension in pregnant women and women in the postpartum period, particularly when used in conjunction with other antihypertensive agents 8
Clinical Applications
- Hydralazine is used to treat severe asymptomatic hypertension in hospitalized patients, often in conjunction with other antihypertensive medications 7
- It is also used to manage acute-onset, severe hypertension during pregnancy and the postpartum period, with the goal of reducing the risk of maternal stroke 8
- The medication may be administered as needed (PRN) or as part of a scheduled antihypertensive regimen, depending on the patient's clinical needs and response to treatment 7
Adverse Effects
- Hydralazine can cause adverse effects such as reflex tachycardia, hemolytic anemia, vasculitis, glomerulonephritis, and a lupus-like syndrome, although these effects are relatively rare 5
- The medication is generally well-tolerated, with most adverse effects becoming less frequent and severe with continued use 9