Guidelines for management of patients with erectile dysfunction indicate that intraurethral and intracavernosal injection therapies represent the second-line treatment available. Efficacy of intracavernosal injections seems superior to that of the intraurethral delivery of drugs, and this may explain the current larger diffusion of the former modality. Safety of these two therapeutic options is well established; however, the attrition rate with these approaches is significant and most patients eventually drop out of treatment. Newer agents with better efficacy-safety profiles and using user-friendly devices for drug administration may potentially increase the long-term satisfaction rate achieved with these therapies. Topical therapy has the potential to become a first-line treatment for erectile dysfunction because it acts locally and is easy to use. At this time, however, the crossing of the barrier caused by the penile skin and tunica albuginea has limited the efficacy of the drugs used.