drbill1-
The "shrinkage" drugs - Finasteride/Proscar or dutasteride/Avodart - don't cause false PSA readings, they do just the opposite. They cause truer PSA readings - that is, they are a truer reflection of PC because they reduce the influence of BPH (enlarged prostate) on the readings. This is what you want to occur. It "resets the baseline PSA" so you have to ignore the pattern from previous readings and just go with them from that point on. Then, if they go up, a biopsy is definitely called for.
about
20% of men get sexual SEs from them. If you do, you can back off of them.
You can also get another blood test called PHI, which is more accurate than PSA or % free PSA and includes both. Here's the link:
Prostate Health Index (PHI)- Allen