Plain Language Summary
Priapism is an erection persisting for over four hours and implicates
emergent intervention to prevent the risk of erectile dysfunction in
future. Oral phosphodiesterase type 5 inhibitors (PDE5is) are used to
treat erectile dysfunction and have rarely been reported to cause
priapism. Looking at the largest international database of individual
case safety reports for drugs (VigiBase), we aimed to explore the
differences among PDE5is of the relative risk of priapism and identify
age groups at risk. We identified reports of priapism corresponding to
sildenafil, tadalafil, vardenafil, and avanafil in VigiBase from 1994 to
2021 and performed disproportionality analysis calculating the reporting
odds ratio (ROR) [i.e., odds of an adverse reaction being reported for
a drug in a dataset] for priapism in PDE5is. We found a very small
risk of priapism with PDE5is compared with other adverse drug reactions.
PDE5i use among young patients was associated with a higher risk of
priapism compared to adults, albeit low. Our analysis further confirmed
that the risk of priapism amongst older men with erectile dysfunction is
extremely rare. This implies that although patient counseling when
prescribing PDE5is for adults seems unneeded, providers should be aware
of the higher risk of priapism in under-age patients.