Why is adenosine often used in hypertensive emergencies?

Adenosine is NOT Used in Hypertensive Emergencies

Adenosine is not a treatment for hypertensive emergencies and should never be used for this indication. This appears to be a fundamental misunderstanding, as adenosine is an antiarrhythmic agent used for supraventricular tachycardia, not a blood pressure-lowering medication for hypertensive crises 1.

Why This Confusion May Exist

Adenosine has cardiovascular effects including vasodilation and can impact blood pressure, but these are side effects, not therapeutic indications 2. The FDA labeling for adenosine specifically warns that it can cause both hypotension AND hypertension as adverse effects, making it entirely inappropriate for blood pressure management 1.

Serious Risks of Adenosine

The FDA warns that adenosine can cause:

• Cardiac arrest, ventricular arrhythmias, and myocardial infarction 1
• Significant hypotension (as a potent peripheral vasodilator) 1
• Clinically significant increases in systolic and diastolic blood pressure (hypertension) 1
• Cerebrovascular accidents (both hemorrhagic and ischemic strokes) associated with its hemodynamic effects 1

Actual First-Line Agents for Hypertensive Emergencies

Labetalol and nicardipine are the recommended first-line intravenous agents for most hypertensive emergencies, as they should be included in the essential drug list of every hospital emergency room 3.

Treatment Algorithm by Clinical Presentation

For malignant hypertension/hypertensive encephalopathy:

• First-line: Labetalol 3
• Alternatives: Nitroprusside, nicardipine, urapidil 3
• Target: Reduce MAP by 20-25% over several hours 3

For acute coronary events:

• First-line: Nitroglycerin 3
• Alternatives: Urapidil, labetalol 3
• Target: Systolic BP <140 mmHg immediately 3

For acute cardiogenic pulmonary edema:

• First-line: Nitroprusside or nitroglycerin with loop diuretic 3
• Alternative: Urapidil with loop diuretic 3
• Target: Systolic BP <140 mmHg immediately 3

For acute aortic dissection:

• First-line: Esmolol plus nitroprusside or nitroglycerin 3
• Alternatives: Labetalol or metoprolol, nicardipine 3
• Target: Systolic BP <120 mmHg and heart rate <60 bpm immediately 3

For eclampsia/severe preeclampsia:

• First-line: Labetalol or nicardipine plus magnesium sulfate 3
• Target: Systolic BP <160 mmHg and diastolic BP <105 mmHg immediately 3

Critical Management Principles

Avoid excessive blood pressure reduction, as decreases exceeding 50% in mean arterial pressure have been associated with ischemic stroke and death 3. The general approach is to reduce mean arterial pressure by no more than 25% in the first hour, then aim for 160/100 mmHg over the next 2-6 hours 4, 5.