Contraindications for Hydralazine
Hydralazine is contraindicated in patients with advanced aortic stenosis, coronary artery disease, and in patients with a history of hypersensitivity to the drug. 1
Absolute Contraindications
- Advanced aortic stenosis 2
- Coronary artery disease (especially with suspected or documented ischemia) 1
- Hypersensitivity to hydralazine 1
- Mitral valvular disease (may increase pulmonary artery pressure) 1
Relative Contraindications and Cautions
Cardiovascular Conditions
- Suspected coronary artery disease - Hydralazine can cause anginal attacks and ECG changes of myocardial ischemia 1
- Cerebrovascular disease - Should be used with caution in patients with cerebral vascular accidents 1
- Tachycardia - Hydralazine can cause reflex tachycardia 3
- Hyperdynamic circulation - May accentuate specific cardiovascular inadequacies 1
Other Medical Conditions
- Advanced renal damage - Should be used with caution 1
- Systemic lupus erythematosus (SLE) - Hydralazine can induce a lupus-like syndrome 1
- Pregnancy - Intravenous hydralazine is contraindicated in pregnancy 2
- Acute myocardial infarction - Intravenous hydralazine should not be used 2
- Bilateral renal artery stenosis - Intravenous hydralazine should be avoided 2
Drug Interactions
- MAO inhibitors - Should be used with caution in patients receiving hydralazine 1
- Diazoxide - Profound hypotensive episodes may occur when used concomitantly 1
- Beta-blockers - Concurrent use requires careful monitoring 3
Clinical Considerations
Acute Hypertensive Management
- Hydralazine is not recommended as a first-line agent for acute hypertensive treatment due to:
- Unpredictable blood pressure response
- Prolonged duration of action (2-4 hours)
- Relatively slow onset of action (10-30 minutes) 2
Monitoring Requirements
- Complete blood counts and antinuclear antibody titer determinations are indicated before and periodically during prolonged therapy 1
- Monitor for peripheral neuritis (paresthesia, numbness, tingling) 1
- Watch for postural hypotension, especially in elderly patients 1
Special Populations
- Elderly patients - No dose adjustment needed, but monitor closely for orthostatic hypotension 2, 3
- Patients with heart failure - May provoke myocardial ischemic events even in the absence of significant tachycardia 4
Alternative Agents
When hydralazine is contraindicated, consider:
- Calcium channel blockers (clevidipine, nicardipine) for patients with contraindications to hydralazine 3
- Nitrates for patients with heart failure who need vasodilation 3
- Fenoldopam for patients with renal impairment 3
Remember that while hydralazine can be effective for blood pressure control, its unpredictability and potential to cause serious adverse effects necessitate careful patient selection and monitoring.