Prescription ED med. Caverject is a brand of injectable alprostadil. Edex is a competing brand. Both must be injected into the penis in order to obtain an erection. Alprostadil is also available as an intraurethral form that's placed in the pee hole. These are alternatives to the more common cialis, levitra, (vardenafil) staxyn, stendra & viagra. Alprostadil can be used in conjunction w/nitrates whereas the oral meds cannot.