Cirazoline is a nonselective agonist of the alpha-1 adrenergic receptor (α1-AR), and an antagonist to the alpha-2 adrenergic receptor. However, it is somewhat sub-type specific to the α1-AR as it is only a partial agonist at the alpha-1B adrenergic receptor (α1B-AR) and alpha-1D adrenergic receptor (α1D-AR), but a full agonist at the alpha-1A ...