5 Alpha Reductase
5 Alpha Reductase is a category of drugs that shrink the prostate, typically taking 4 to 6 months to maximal effect. Some examples include: Finasteride (Proscar), Dutasteride (Avodart). Although they take longer to work, the 5 alpha-reductase inhibitors are useful in very large prostate diagnoses. 5 alpha-reductase may cause erectile dysfunction, reduced volume of semen, and breast tenderness or enlargement.