I mean, that’s kinda a risk with any ED medicine from what I understand. All of those kind of medicines have warnings about if you have an erection lasting more than x hours that you need to immediately see a Dr. When you’re erect, the blood is trapped in your penis, and if it’s trapped for too long it can cause tissue damage and tissue death.

So it’s a risk with all/most ED medicines, just significantly more of a risk with spider bites.