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What drugs are used for treatment of hypertensive emergencies?
Fortunately, many drugs are available, each with their own advantages and disadvantages. Nitroprusside is the most widely available, has the shortest time to effect, and can be easily titrated up or down as needed. It breaks down to cyanide and thiocyanate, which can cause metabolic acidosis, an anion gap, blurred vision, tinnitus, and/or confusion; the risk of these adverse effects increases with the dose and duration of infusion. The newer agents—esmolol, fenoldopam, and clevidipine—are reasonably short-acting agents that are a beta blocker, dopamine-1 agonist, and calcium antagonist, respectively; these attributes can be helpful in certain clinical scenarios.
Useful Drugs for Hypertensive Emergencies
| DRUG | ONSET OF ACTION | ELIMINATION HALF-LIFE | USUAL DOSE (IV) | POSITIVE ATTRIBUTES | RISKS |
|---|---|---|---|---|---|
| Sodium nitroprusside | Seconds | ∼2 min | 0.25–8.0 μg/kg per minute | Very effective; fast-acting, easily titrated, or stopped | Photosensitive; metabolized to cyanide and thiocyanate |
| Nitroglycerin | 2–5 min | 1–4 min | 5–100 mcg/min | Useful for coronary ischemia | Methemoglobinemia; special tubing needed |
| Labetalol | 5–10 min | 5–6 h | 20–80 mg bolus every 10–15 min, or 0.5–2.0 mg/min infusion | Useful for coronary ischemia; oral formulation available | Asthma, acute left ventricular dysfunction |
| Enalaprilat | 15–30 min | 11 h | 1.25–5.0 mg every 6 h | Useful in left ventricular dysfunction | Avoid in acute myocardial infarction |
| Nicardipine | 2–5 min | 45 min, 14 h | 5 mg/h, increased to 15 mg/h | Useful for cardiac ischemia | Interacts with cimetidine, cyclosporine; oral formulation available |
| Esmolol | 5–10 min | 9 min | 250–500 mcg/kg per minute for 1 min, then 50–100 mcg/kg per minute | Useful for aortic dissection and perioperative state | Asthma, left ventricular dysfunction |
| Fenoldopam | 2–5 min | 5 min | 0.1–0.3 mcg/kg per minute initially, increase 0.1–0.2 every 15 min | Improves several parameters of renal function | Raises intraocular pressure; may cause hypokalemia |
| Clevidipine | 2–4 min | ∼1 min | 1–2 mg/h, increased every 90 s | Useful for cardiac ischemia, perioperative state | Photosensitive; comes in lipid emulsion |
