Funny, but if it last that long I think it could also mean something is wrong with the heart too.
I knew a medical worker who said Viagra (and pills like it) was one of the worst legal drugs, as sells have gone up, so have heart attacks or strokes after taking them.
Basically ones heart need to be in shape enough for them... but the ones that need it for E.D. the most are also the ones with weaker hearts... and they should build up the heart muscles first before being allowed the E.D. drug.
Too much of an erection is no fun for anyone. Many years back after no real success with Viagra and similar, I tried the direct injection treatment. It worked so well it was too painful to touch let alone any kind of sex, and I had to wait an hour before it subsided.