Finasteride, all are false except:

Ans: a (Used in androgenic alopecia) Ref:Goodman and Gilman, 11th ed, p. 10225 ALPHA-REDUCTASE INHIBITORS:Finasteride is an inhibitor of 5a-reductase, especially the Type II isozyme; dutasteride is a dual inhibitor of types I and II; both drugs block the conversion of testosterone to dihydrotestosterone, especially in the male external genitalia.These agents are approved for benign prostatic hyperplasia. When administered to men with moderately severe symptoms due to obstruction of urinary tract outflow, serum and prostatic concentrations of dihydrotestosterone decrease, prostatic volume decreases, and urine flow rate increases. The beneficial effects are seen maximally only ~6 months after treatment. Petients with larger prostate (volume > 40 ml) obtain greater relief than those with smaller gland. The relief of obstruction is less compare to that of alpha 1 blockers or surgery. Finasteride primarily reduces static component of obstruction, while alpha 1 blockers overcome the dynamic component.Finasteride also is approved for use in the treatment of male pattern baldness.Impotence is a well-documented, albeit infrequent, side effect of this use(Loss of libido has been mentioned as side effect in Tripathi but not in Katzung or Goodman & Gilman)