HydrALAzine
Classification
Antihypertensive, vasodilator
Indications
CCP: Hypertensive emergency
CCP: Hypertensive emergency in pregnancy or postpartum
Contraindications
- Hypersensitivity to hydralazine
- Coronary artery disease
- Mitral valve rheumatic heart disease
- Severe tachycardia and heart failure with high cardiac output
- Myocardial insufficiency due to mechanical obstruction (aortic or mitral stenosis, constrictive pericarditis)
- Isolated right ventricular heart failure due to pulmonary hypertension
- Acute dissecting aortic aneurysm
- Porphyria
Adult dosages
CCP: Hypertensive emergency
- 10-20 mg IV/IM every 4-6 hours as required
CCP: Hypertensive emergency in pregnancy or postpartum
- 5-10 mg IV; may repeat 5-10 mg doses every 20 minutes if blood pressure continues to exceed thresholds
Consider alternative agent if blood pressure remains elevated after a total of 20-30 mg
Caution: Significant drug interactions exist. Consult drug interaction database for additional information.
Pediatric Considerations And Dosing
CCP: Hypertensive emergency
- 0.1-0.2 mg/kg/dose every 4-6 hours, titrated as required; usual dose range: 0.2-0.6 mg/kg/dose
Caution: Significant drug interactions exist. Consult drug interaction database for additional information.
How Supplied
Vial: 20 mg/mL in 1 mL vial
Mechanism Of Action
Causes direct vasodilation of arterioles, decreasing systemic resistance. May occur due to inhibition of calcium release from sarcoplasmic reticulum and inhibition of myosin phosphorylation in arterial smooth muscle cells.
Pharmacokinetics
Intravenous:
- Onset: 5-20 minutes
- Peak: 10-80 minutes
- Duration: 1-4 hours
Adverse Effects
- Cardiovascular: Acute myocardial infarction, angina pectoris, edema, flushing, hypotension, myocardial stimulation, palpitations, paradoxical response to antihypertensive, tachycardia
- Dermatologic: Pruritus, skin rash (including eczema), urticaria
- Gastrointestinal: Anorexia, constipation, diarrhea, nausea, paralytic ileus, vomiting
- Genitourinary: Difficulty in micturition
- Hematologic & oncologic: Agranulocytosis, decreased hemoglobin, decreased red blood cells, eosinophilia, leukopenia, lymphadenopathy, purpuric disease, splenomegaly
- Hepatic: Hepatitis
- Nervous system: Chills, dizziness, headache, peripheral neuritis, psychotic reaction (including anxiety, depression, disorientation, euphoria, hypomania, nervousness)
- Neuromuscular & skeletal: Arthralgia, muscle cramps, tremor
- Ophthalmic: Conjunctivitis, lacrimation
- Respiratory: Dyspnea, nasal congestion
- Miscellaneous: Fever
Source: HydrALAzine. In: Lexicomp Online, UpToDate, Waltham, MA. (Accessed November 20, 2020.)
Warning And Precautions
Consider concurrent use of beta blocker: hydrALAzine is associated with reflex tachycardia.
Drug Interactions
Caution: Significant drug interactions exist. Consult drug interaction database for additional information.