Tamsulosin and Resting Penile Size
Tamsulosin is not known to increase the resting (flaccid) size of the penis. [1]
Documented Penile-Related Adverse Effects
Tamsulosin can cause sexual side effects, including ejaculatory and erectile-related adverse effects. [1] Tamsulosin is associated with priapism, which is a persistent, often painful erection that is unrelated to sexual arousal. [1] Priapism is described as very rare in prescribing information. [1]
Expected Effect on Size Versus Erection Events
Priapism can produce a sustained erect state rather than a true increase in baseline resting size. [1] Persistent erectile dysfunction is a potential consequence if priapism is not treated promptly. [1]
Safety Signals Requiring Urgent Care
Urgent medical evaluation is indicated for any erection lasting more than several hours while taking tamsulosin. [3]
Evidence Summary
Published drug safety information lists priapism as a very rare penile-related adverse effect and does not list flaccid size enlargement as an adverse effect. [1]
Clinical Interpretation for the Resting State
A perceived increase in resting fullness or size after starting tamsulosin is not supported by the known adverse-effect profile. [1]