Hypertensive emergency secondary to atropine

Atropine, a competitive antagonist of acetylcholine muscarinic receptors, is commonly used to treat severe bradycardia by blocking parasympathetic activity. We present a rare case of hypertensive emergency following atropine administration, with only one previous report in the literature.

A 78-year-old woman with essential hypertension and hypercholesterolemia was admitted to the cardiac intensive care unit for non-ST segment elevation myocardial infarction. During coronary angiography, an occlusion of the right coronary artery was identified. While removing the diagnostic catheter through the right radial artery, the patient experienced intense pain and discomfort, accompanied by a vasovagal reflex characterized by bradycardia and hypotension. Intravenous atropine (0.5 mg) was administered, leading to a rapid rise in heart rate with frequent ventricular ectopy. Subsequently, a progressive and exaggerated elevation in arterial blood pressure occurred, peaking at 294/121 mmHg approximately 10 min after atropine administration. The patient developed hypertensive acute pulmonary edema, successfully treated with intravenous nitroglycerine (10 mg) and furosemide (60 mg). Blood pressure normalized after approximately 14 min.

The exact mechanism of atropine-induced hypertensive emergency remains unknown. While hypertensive emergencies with atropine are exceedingly rare, healthcare professionals should be aware of this potential effect and be prepared for prompt intervention.