A drug 'X' primarily reduces the static component of urinary obstruction in benign hyperophy of prostate and takes more than 3 months to exe its beneficial effect. Which of the following is 'X'?

5-a-reductase inhibitors: Finasteride reduce the static component of urinary obstruction in BHP--> Delayed action >3months Selective a1 blockers are used to relieve the dynamic obstruction in BHP-->provides rapid symptomatic relief.