1. A medication that blocks the effects of adrenaline and noradrenaline on alpha-adrenergic receptors, used to treat high blood pressure and pheochromocytoma.
Usage: medical/pharmaceutical; often used in plural form 'phentolamine' or 'phentolamine mesylate' in clinical contexts

Examples

• The doctor prescribed phentolamine to manage the patient's dangerously elevated blood pressure.
• Phentolamine is commonly used before surgery to treat patients with pheochromocytoma.
• The medication works by blocking alpha-adrenergic receptors in blood vessels.
• Phentolamine has a rapid onset of action, making it useful in acute hypertensive crises.
• The patient received an intravenous dose of phentolamine in the emergency room.