> For the complete documentation index, see [llms.txt](https://zekkeri.gitbook.io/upvote/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://zekkeri.gitbook.io/upvote/how-do-pde5-inhibitors-such-as-viagra-and-cialis-work-to-treat-ed.md).

# How do PDE5 inhibitors, such as Viagra and Cialis, work to treat ED?

They enhance blood flow to the penis by inhibiting the enzyme PDE5, facilitating erections.

[![](https://i.imgur.com/eNKuqIn.png)](https://agentpills.com/go/)