How does drug effect a psa test?

Which drug: The psa is a test for prostate specific antigen. Usually drugs do not affect this evaluation -- unless you are taking drugs to oppose prostate growth or after radiation treatment.

Here are some...: - 5-alpha reductase inhibitors such as Finasteride or Dutasteride will decrease psa by some 40-50% in 2-4 months; - antibiotics may make psa down if being used for treating bacterial prostatitis; - lhrh analog such as leupran and others for prostate cancer will greatly suppress psa; - antihistamine may possibly decrease psa if being used for treating "allergic" prostatitis; this is just a thought.