Hydralazine

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.