otter17 wrote:And one thing that may suggest at least a degree of tolerance/tachyphylaxis, is that my side effects from the same dose of viagra (stuffy nose, flushing), seem to be less than previously too
The drug companies deny it but I think there is some tolerance.
I've basically been taking these drugs daily for years. Eventually no effects and no side effects either.
However, when I take a break and return, side effects return, as well as little bit more of the desired effect. Not quite enough unfortunately.
I do suspect that some of the off-brand generics they sell cheaply in U.S. pharmacies now are no good. I definitely suspect a quality control issue.