From the Guidelines
Hydralazine should only be considered for hypertension treatment when other medications have failed to adequately control blood pressure, specifically in cases of resistant hypertension or hypertensive emergencies, as stated in the 2024 ESC guidelines 1. When considering hydralazine for hypertension treatment, it is essential to note that it is not a first-line agent due to its side effects and the availability of more effective and better-tolerated antihypertensives. The usual oral dosage ranges from 25-100 mg taken 2-4 times daily, with a maximum daily dose of 300 mg. For hypertensive emergencies, it can be administered intravenously at 10-20 mg doses, as outlined in the 2018 ACC/AHA/AAPA/ABC/ACPM/AGS/APHA/ASH/ASPC/NMA/PCNA guideline 1.
Some key points to consider when prescribing hydralazine include:
- It works as a direct vasodilator, relaxing vascular smooth muscle primarily in arterioles, which reduces peripheral resistance and lowers blood pressure.
- Its common side effect of reflex tachycardia explains why it's often prescribed alongside beta-blockers or other heart-rate controlling medications.
- Other notable side effects include headache, fluid retention, and a lupus-like syndrome with prolonged use at higher doses.
- According to the 2024 ESC guidelines, hydralazine should only be considered after maximally tolerated triple-combination therapy and when spironolactone, eplerenone, or beta-blockers are not effective or tolerated 1.
In clinical practice, hydralazine's use should be guided by the most recent and highest-quality evidence, prioritizing patient outcomes in terms of morbidity, mortality, and quality of life. As such, hydralazine's role in hypertension management is generally reserved for specific scenarios where its benefits outweigh its risks and limitations, as supported by the 2024 ESC guidelines 1.
From the FDA Drug Label
In hypertensive patients with normal kidneys who are treated with hydrALAZINE, there is evidence of increased renal blood flow and a maintenance of glomerular filtration rate. Hydralazine is used for hypertension in patients with normal kidneys.
- Hypertension treatment: Hydralazine can be used to treat hypertension, particularly in patients with normal kidney function.
- Caution in specific cases: However, it should be used with caution in patients with suspected coronary artery disease, cerebral vascular accidents, or advanced renal damage 2.
From the Research
Hydralazine Use in Hypertension
- Hydralazine is a direct-acting vasodilator that has been used for the treatment of hypertension since the 1950s 3.
- It is still widely used in developing countries due to its lower cost, although it has largely been replaced by newer antihypertensive drugs with more acceptable tolerability profiles 3.
- Hydralazine may be used to reduce blood pressure in patients with primary hypertension, but its effect on clinical outcomes remains uncertain 3.
- Intravenous hydralazine can be used as an alternative when rapid arterial pressure reduction is needed, such as in hypertensive crisis 4.
Comparison with Other Antihypertensive Drugs
- Hydralazine is not typically recommended as a first-line treatment for hypertension in patients with coronary artery disease, with beta blockers and ACE inhibitors or ARBs being preferred 5.
- In elderly patients with essential hypertension, diuretics or calcium-blocking drugs are more effective at lowering systolic blood pressure than hydralazine 6.
- In pregnancy, hydralazine is one of the recommended first-line treatments for severe hypertension, although nifedipine may be superior in terms of efficacy 7.