Any physicians prescribed propecia (finasteride) or proscar and had patients experience adverse affects such as ed, low testosterone, etc, ? Irreversible sides?

Both affect ED. Both affect ED, but this is temporary and ED should subside after medication is discontinued.
Proscar (finasteride) side effects. This is an anecdote. In my last practice I had one patient, a 40 year old male, who underwent hair transplants in 2008 and took Proscar (finasteride) as part of the protocol. He had previously been sexually vigorous, but reported that 4 months larter he experienced total loss of libido and erections, harming his relationships. His testosterone test and pituitary hormones were normal. The cause is not yet prove.