Health.am| Table 11-12. Drugs for hypertensive emergencies and urgencies. | ||||||
| Agent | Action | Dosage | Onset | Duration | Adverse Effects | Comments |
PARENTERAL AGENTS (INTRAVENOUSLY UNLESS NOTED) | ||||||
Nitroprusside (Nipride) | Vasodilator | 0.25-10 mcg/kg/min | Seconds | 3-5 minutes | GI, CNS; thiocyanate and cyanide toxicity, especially with renal and hepatic insufficiency; hypotension. | Most effective and easily titratable treatment. Use with β-blocker in aortic dissection. |
Nitroglycerin | Vasodilator | 0.25-5 mcg/kg/min | 2-5 minutes | 3-5 minutes | Headache, nausea, hypotension, bradycardia. | Tolerance may develop. Useful primarily with myocardial ischemia. |
Labetalol (Normodyne, Trandate) | β- and α-Blocker | 20-40 mg every 10 minutes to 300 mg; 2 mg/min infusion | 5-10 minutes | 3-6 hours | GI, hypotension, bronchospasm, bradycardia, heart block. | Avoid in congestive heart failure, asthma. May be continued orally. |
Esmolol (Brevibloc) | β-Blocker | Loading dose 500 mcg/kg over 1 minute; maintenance, 25-200 mcg/kg/min | 1-2 minutes | 10-30 minutes | Bradycardia, nausea. | Avoid in congestive heart failure, asthma. Weak antihypertensive. |
Fenoldopam (Corlopam) | Dopamine receptor agonist | 0.1-1.6 mcg/kg/min | 4-5 minutes | < 10 minutes | Reflex tachycardia, hypotension,  intraocular pressure. | May protect renal function. |
Nicardipine (Cardene) | Calcium channel blocker | 5 mg/h; may increase by 1-2.5 mg/h every 15 minutes to 15 mg/h | 1-5 minutes | 3-6 hours | Hypotension, tachycardia, headache. | May precipitate myocardial ischemia. |
Enalaprilat (Vasotec) | ACE inhibitor | 1.25 mg every 6 hours | 15 minutes | 6 hours or more | Excessive hypotension. | Additive with diuretics; may be continued orally. |
Furosemide (Lasix) | Diuretic | 10-80 mg | 15 minutes | 4 hours | Hypokalemia, hypotension. | Adjunct to vasodilator. |
Hydralazine (Apresoline) | Vasodilator | 5-20 mg intravenously or intramuscularly (less desirable); may repeat after 20 minutes | 10-30 minutes | 2-6 hours | Tachycardia, headache, GI. | Avoid in coronary artery disease, dissection. Rarely used except in pregnancy. |
Diazoxide (Hyperstat) | Vasodilator | 50-150 mg repeated at intervals of 5-15 minutes, or 15-30 mg/min by intravenous infusion to a maximum of 600 mg | 1-2 minutes | 4-24 hours | Excessive hypotension, tachycardia, myocardial ischemia, headache, nausea, vomiting, hyperglycemia. Necrosis with extravasation. | Avoid in coronary artery disease and dissection. Use with β-blocker and diuretic. Mostly obsolete. |
Trimethaphan (Arfonad) | Ganglionic blocker | 0.5-5 mg/min | 1-3 minutes | 10 minutes | Hypotension, ileus, urinary retention, respiratory arrest. Liberates histamine; use caution in allergic individuals. | Useful in aortic dissection. Otherwise rarely used. |
ORAL AGENTS | ||||||
Nifedipine (Adalat, Procardia) | Calcium channel blocker | 10 mg initially; may be repeated after 30 minutes | 15 minutes | 2-6 hours | Excessive hypotension, tachycardia, headache, angina, myocardial infarction, stroke. | Response unpredictable. |
Clonidine (Catapres) | Central sympatholytic | 0.1-0.2 mg initially; then 0.1 mg every hour to 0.8 mg | 30-60 minutes | 6-8 hours | Sedation. | Rebound may occur. |
Captopril (Capoten) | ACE inhibitor | 12.5-25 mg | 15-30 minutes | 4-6 hours | Excessive hypotension. | |
GI = gastrointestinal; CNS = central nervous system; ACE = angiotensin-converting enzyme. | ||||||