Radical prostatectomy is a surgery to remove the entire prostate gland that is often performed to treat prostate cancer. One common side effect of radical prostatectomy is erectile dysfunction (ED), because the nerves that control erections may be affected. Therefore, most medical experts recommend that patients complete a penile rehabilitation program to regain erectile functioning after this procedure.

Two common components of a penile rehabilitation program are phosphodiesterase type 5 (PDE5) inhibitors (oral ED medications like tadalafil, sildenafil, vardenafil, and avanafil) and intracavernosal injections (injections of medication directly into the penis to create an erection). While patients generally tolerate these treatments well, occasionally they can cause a serious medical condition called priapism, which is an erection lasting over 4 hours.

To gain more information on how the risk of developing priapism might be minimized, a new study looked at the risk of priapism between two groups of patients using ED medications for penile rehabilitation.

One group used tadalafil with intracavernosal injection therapy, while the other group used sildenafil with intracavernosal injection therapy. When compared to sildenafil and other PDE5 inhibitors, tadalafil is known to have a longer duration of effect. By exploring the potential risks of priapism of these two ED treatment strategies, this study aimed to evaluate the safety of each combination of medications.

The study included 476 men who were undergoing penile rehabilitation after prostate removal. The average age of the individuals was 62 years, and the average time after radical prostatectomy was 5.2 months. Participants were split into two groups: 112 tadalafil users and 364 sildenafil users. All of the participants also used intracavernosal injection therapy.

The cohort comprised of those taking tadalafil took 5 mg daily, and the cohort of those taking sildenafil took 25 mg on non-injection days. All participants’ demographic and medical details were collected.

For this study, priapism was defined as an erection lasting ≥4 hours and a prolonged erection was defined as an erection lasting ≥2 hours. Patients took a medication called pseudoephedrine if an erection lasted 2 hours, contacted medical staff at 3 hours, and sought emergency care at 4 hours.

Overall, the study found a low incidence of priapism (1.7% for tadalafil, 1.4% for sildenafil), with no significant difference between the two. However, the tadalafil group had a higher occurrence of prolonged erections (6.3% vs. 3.3%), especially during initial home injections.

In the end, the results of this study emphasize the importance of ongoing monitoring and education for patients who are using PDE5 inhibitors and intracavernosal injection therapy to minimize adverse events. This study contributes valuable information to understanding the safety of individuals undergoing a penile rehabilitation program after radical prostatectomy.

References:

• Furtado, T. P., Miranda, E. P., Deveci, S., Jenkins, L., Narus, J., Nelson, C., & Mulhall, J. P. (2024). Erectile response profiles of men using PDE5 inhibitors combined with intracavernosal injections as part of a penile rehabilitation program after radical prostatectomy. The Journal of Sexual Medicine, 21(1), 29–32. https://doi.org/10.1093/jsxmed/qdad144