An intracavernous (or intracavernosal) injection is an injection into the base of the penis. This injection site is often used to administer medications to check for or treat erectile dysfunction in adult men (in e.g. combined intracavernous injection and stimulation test). The more common medications administered in this manner include Caverject, Trimix (Prostaglandin, Papaverine, and Phentolamine), Bimix (Papaverine and Phentolamine), and Quadmix (Prostaglandin, Papaverine, Phentolamine, and either Atropine or Forskolin). These medications are all types of vasodilators and cause tumescence within 10-15 minutes. Common side effects include, but are not limited to, priapism, bruising, fibrosis, Peyronies, and pain.