Abstract Treatment of priapism with intracavernous alpha-adrenergic agonist vasoconstrictor agents is well accepted, particularly for patients with priapism secondary to intracavernous injections of papaverine, phentolamine and/or prostaglandin E1. Although many alpha-adrenergic agonists are commercially available, phenylephrine is preferred because it has potent and selective alpha1-adrenergic stimulatory properties, which can decrease arteriolar flow to the cavernous sinusoids, and no beta 1-stimulatory effect, which could cause arrhythmias and angina in susceptible patients. Before intracavernous injection or irrigation an alpha-adrenergic agonist must be diluted. However, no readily available reference source lists this information. Therefore, we prepared a chart for extemporaneous preparation of dilutions of alpha-adrenergic agonists for intermittent injection or irrigation.