From the Guidelines
Hydralazine is contraindicated in patients with advanced aortic stenosis, coronary artery disease, and those with soybean, soy product, egg, and egg product allergy, and should be used with caution in elderly patients and those with cerebrovascular disease. The side effects of hydralazine include headache, palpitations, tachycardia, dizziness, and fluid retention, which often requires concurrent diuretic therapy 1. More serious adverse effects include a lupus-like syndrome, peripheral neuropathy, and blood dyscrasias. Hydralazine is also contraindicated in patients with concurrent beta-blocker therapy, bradycardia, or decompensated heart failure, and may worsen heart failure 1.
Important Considerations
- Hydralazine requires careful dosing, typically starting at 10-25mg three to four times daily, with gradual titration to a maximum of 200mg daily 1.
- Due to its first-pass metabolism, dosing must be frequent, and it's often used as part of combination therapy rather than monotherapy.
- Patients should be monitored for development of positive antinuclear antibodies, which may indicate drug-induced lupus, especially in those on long-term therapy.
- Intra-arterial BP monitoring is recommended to prevent “overshoot” and lower dosing adjustment is required for elderly patients 1.
- Tachyphylaxis is common with extended use, and cyanide toxicity with prolonged use can result in irreversible neurological changes and cardiac arrest 1.
Contraindications
- Advanced aortic stenosis
- Coronary artery disease
- Soybean, soy product, egg, and egg product allergy
- Defective lipid metabolism
- Concurrent beta-blocker therapy
- Bradycardia
- Decompensated heart failure
- Reactive airways disease or chronic obstructive pulmonary disease
- Pregnancy
- Acute myocardial infarction or bilateral renal artery stenosis
Special Considerations
- Hydralazine is especially useful in hyperadrenergic syndromes and hypertensive emergencies induced by catecholamine excess 1.
- It should be used with caution in patients with cerebrovascular disease, as rapid blood pressure reduction may reduce cerebral perfusion.
- The selection of an antihypertensive agent should be based on the drug’s pharmacology, pathophysiological factors underlying the patient’s hypertension, degree of progression of target organ damage, the desirable rate of BP decline, and the presence of comorbidities 1.
From the FDA Drug Label
PRECAUTIONS General Myocardial stimulation produced by hydrALAZINE can cause anginal attacks and ECG changes of myocardial ischemia. The drug has been implicated in the production of myocardial infarction. It must, therefore, be used with caution in patients with suspected coronary artery disease The “hyperdynamic” circulation caused by hydrALAZINE may accentuate specific cardiovascular inadequacies. For example, hydrALAZINE may increase pulmonary artery pressure in patients with mitral valvular disease. The drug may reduce the pressor responses to epinephrine. Postural hypotension may result from hydrALAZINE but is less common than with ganglionic blocking agents It should be used with caution in patients with cerebral vascular accidents. Peripheral neuritis, evidenced by paresthesia, numbness, and tingling, has been observed. Blood dyscrasias, consisting of reduction in hemoglobin and red cell count, leukopenia, agranulocytosis, and purpura, have been reported. CONTRAINDICATIONS Hypersensitivity to hydrALAZINE; coronary artery disease; mitral valvular rheumatic heart disease.
The side effects of Hydralazine for hypertension management include:
- Myocardial stimulation leading to anginal attacks and ECG changes
- Postural hypotension
- Peripheral neuritis (paresthesia, numbness, and tingling)
- Blood dyscrasias (reduction in hemoglobin and red cell count, leukopenia, agranulocytosis, and purpura)
The contraindications of Hydralazine are:
From the Research
Side Effects of Hydralazine
- Reflex tachycardia, hemolytic anemia, vasculitis, glomerulonephritis, and a lupus-like syndrome are some of the adverse effects related to hydralazine that have been reported in the literature 3
- Hypotension is a common adverse event associated with intravenous hydralazine, with 11 patients experiencing it in one study 4
- Other symptoms reported by patients taking hydralazine include those similar to prazosin, with no increased reporting frequency when the two drugs are used in combination 5
Contraindications of Hydralazine
- 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 3
- Hydralazine may not be useful for treating hypertension in many hospitalized patients and may cause harm if used inappropriately, particularly in non-urgent cases 4
- The use of intravenous hydralazine is often unjustified, with only 2% of patients having evidence of an urgent hypertensive condition in one study 4
Special Considerations
- The efficacy and tolerability of slow-release hydralazine administered once daily were compared with those of conventional hydralazine given two to four times a day, with no differences found in the incidence of side effects 6
- Once-daily treatment with conventional hydralazine was unsatisfactory, as its hypotensive effect waned at 24 h, while slow-release hydralazine gave satisfactory control for 24 hours in both rapid and slow acetylators 7