Hydralazine
| Drug monograph · NCLEX study reference | |
| Therapeutic class | Antihypertensive |
|---|---|
| Pharmacologic class | Direct arteriolar vasodilator |
| Onset / peak / duration | PO onset 20 to 30 minutes; IV within minutes; duration 2 to 4 hours. |
| Half-life / level | Half-life 3 to 7 hours; no routine level. |
| Routes | PO (oral), IV |
| High-alert (ISMP) | No |
| Black box warning | None |
| Antidote / reversal | Supportive care. |
| Pregnancy / lactation | Used in obstetric hypertension under specialist care. |
Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.
Hydralazine — Antihypertensive; Direct arteriolar vasodilator.
Identification
- Therapeutic class: Antihypertensive.
- Pharmacologic class: Direct arteriolar vasodilator.
Pharmacology
- Mechanism of action: Directly relaxes arteriolar smooth muscle, reducing afterload.
- Onset / peak / duration: PO onset 20 to 30 minutes; IV within minutes; duration 2 to 4 hours.
- Half-life / therapeutic level: Half-life 3 to 7 hours; no routine level.
Clinical use
- Indications: Hypertension, heart failure (with nitrates), hypertensive emergencies, hypertension in pregnancy.
- Usual dose, route, frequency: 10 to 50 mg PO four times daily; IV for emergencies.
- Maximum dose / adjustments: Up to about 300 mg/day; slow acetylators are prone to lupus-like syndrome.
Safety
- Contraindications: Coronary artery disease, mitral valve rheumatic heart disease.
- Black box warning: None.
- Interactions: Other antihypertensives (additive hypotension), NSAIDs (reduced effect), MAO inhibitors.
- Pregnancy / lactation: Used in obstetric hypertension under specialist care.
- High-alert: No.
Adverse effects
- Common side effects: Reflex tachycardia, headache, flushing, palpitations.
- Serious effects to report: Drug-induced lupus-like syndrome (joint pain, rash, fever), severe hypotension.
- Antidote / reversal: Supportive care.
Nursing process
- Assessment before administration: Blood pressure, heart rate.
- Interventions during therapy: Often paired with a beta blocker to limit reflex tachycardia.
- Monitor: Blood pressure, heart rate, antinuclear antibody with long-term use.
- Evaluation / expected outcome: Lowered blood pressure.
Patient teaching
- Patient teaching: Report joint pain or rash.
- Notify provider if: Persistent joint pain, rash, fever, chest pain.
- Administration tips: Take consistently with food.