Drug

Dose

Onset/duration of action

Contraindications

Adverse effectsa

Special indications

Enalaprilat

0.625-1.25 mg IV bolus

5-15 min/4-6 h

History of angioedema

Acute LV failure; avoid in acute MI

Fenoldopam

0.1-0.3 microg/kg/min as IV infusion

<5 min/30 min

Tachycardia, headache, nausea, flushing

In most hypertensive emergencies; use with caution in patients with glaucoma

Hydralazine

10-20 mg IV

10-20 min/1-4 h

Tachycardia, flushing, headache, vomiting, worsening of angina pectoris

Eclampsia

Nicardipine

5-15 mg/h IV infusion, starting dose 5 mg/h, increase every 15-30 min by 2.5 mg until target BP is achieved, then decrease to 3 mg/h

5-15 min/30-40 min

Liver failure

Headache, reflex tachycardia

In most hypertensive emergencies except for acute heart failure; use with caution in patients with coronary ischemia

Nitroglycerin

5-100 microg/min as IV infusion

2-5 min/5-10 min

Headache, vomiting, methemoglobinemia, development of tolerance with prolonged use

Myocardial ischemia, heart failure

Sodium nitroprusside

0.25-10 microg/kg/min as IV infusion (max dose may be administered only for 10 min)

Immediate/1-2 min

Liver/kidney failure (relative)

Nausea, vomiting, muscle cramps, sweating, cyanide and thiocyanate poisoning

In most hypertensive emergencies; use with caution in patients with high intracranial pressure or CKD

Esmolol

500-1000 microg/kg IV bolus followed by 50-100 microg/kg/min as IV infusion; bolus may be repeated after 5 min or infusion rate increased to 300 microg/min

1-2 min/10-30 min

Second- or third-degree AV block, systolic heart failure, asthma, bradycardia

Nausea, AV block

Aortic dissection, perioperative emergencies

Labetalol

20-80 mg IV bolus every 10 min or 0.5-2 mg/min as IV infusion

5-10 min/3-6 h

Second- or third-degree AV block, systolic heart failure, asthma, bradycardia

Vomiting, scalp tingling, burning sensation in throat, dizziness, AV block

In most hypertensive emergencies except for acute heart failure

Phentolamine

5-15 mg IV

1-2 min/10-30 min

Tachycardia, headache, flushing

Catecholamine excess (eg, pheochromocytoma)

Urapidil (not available in Canada)

12.5-25 mg as bolus injection; 5-40 mg/h as continuous infusion

1-5 min/1-2 h

Dizziness, headache, nausea, vomiting, dyspnea, palpitations, tachycardia or bradycardia, chest discomfort, arrhythmia

In most hypertensive emergencies

a Each of these drugs may cause hypotension.