Hydralazine for Hypertension Management
Hydralazine is recommended as a step 3 option when hypertension persists despite treatment with a combination of ACE inhibitor/ARB, beta-blocker, MRA, and diuretic. 1
Appropriate Use of Hydralazine in Hypertension Management
Treatment Algorithm
- First-line therapy should include ACE inhibitors (or ARBs), beta-blockers, and MRAs due to their proven benefits in reducing hospitalization and mortality 1
- Second-line therapy involves adding a thiazide diuretic or switching to a loop diuretic if the patient is already on a thiazide 1
- Third-line therapy includes adding either:
- Fourth-line therapy may include felodipine (Class IIa, Level B recommendation) 1
Mechanism and Administration
- Hydralazine is a direct-acting vasodilator that causes unpredictable blood pressure responses 2, 3
- Effects begin within 10-30 minutes of administration and last 2-4 hours 2
- For chronic hypertension management, hydralazine is typically administered 2-3 times daily (100-200 mg/day total) rather than as a single dose 2
Important Considerations and Cautions
Adverse Effects
- Hydralazine commonly causes reflex tachycardia and sodium/water retention, which may counteract its antihypertensive effect 2, 4
- To mitigate these effects, hydralazine should be used in combination with a beta-blocker and diuretic 2
- Other potential adverse effects include hemolytic anemia, vasculitis, glomerulonephritis, and a lupus-like syndrome 4
Limitations in Acute Settings
- Hydralazine is not recommended as a first-line agent for acute blood pressure management due to its unpredictable response and prolonged duration of action 2, 3, 5
- For hypertensive emergencies, newer agents such as clevidipine, nicardipine, fenoldopam, and labetalol are preferred due to their better safety profiles and titratable effects 6, 5
Use in Resistant Hypertension
- In patients with resistant hypertension where spironolactone is not effective or tolerated, hydralazine may be considered after trying other options like eplerenone, beta-blockers, or alpha-blockers 1
Special Populations
Heart Failure
- In patients with symptomatic heart failure (NYHA class II-IV) and left ventricular systolic dysfunction, hydralazine is recommended as a step 3 option when hypertension persists despite optimal therapy 1
Acute Settings
- For severe hypertension requiring IV therapy, hydralazine is considered a second-line option after labetalol, methyldopa, or nifedipine 1
- Caution is warranted as IV hydralazine use is often unjustified in hospitalized patients and associated with variable BP responses and hypotension 7
Remember that hydralazine should be used within the context of a comprehensive antihypertensive regimen, not as monotherapy, and careful monitoring is essential due to its variable effects and potential for adverse reactions.