Adrenoceptor agonists drug list

The two imidazolines, tolazoline and phentolamine, are primarily of historical interest. Tolazoline was first developed in 1939. The structures of these two drugs resemble the a-adrenoceptor agonists listed in Table 9-3. They are competitive antagonists. Tolazoline is rather weak as a vasodilator and its a-blockade is transient. The drug actually has a multifaceted pharmacological profile. For example, it can exhibit sympathomimetic activity or enhancement of response to sympathetic nerve stimulation. 

Several imidazole compounds with peripheral a-adrenoceptor stimulant properties, but no corresponding P-effects, are listed in Table 9-3. Unlike with other direct and indirect agonists, there is no significant neuronal uptake mechanism involved. These first four drugs are used mainly as decongestants on nasal mucosa as well as on ocular membranes. A degree of a2 central stimulation likely accounts for some of the sedation encountered... 

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