5-alpha-reductase inhibitors

5-α-re·duc·tase in·hib·i·tors

(rĕ-dŭk'tās in-hib'i-tŏrz) Drugs that inhibit the action of 5α-reductase, resulting in lower levels of prostatic dihydrotestosterone, produced by the enzyme from testosterone as the primary androgen in the prostate.