The chemical nepetalactone is to credit for your kitty's crazy reaction to catnip. The chemical, which is a mild hallucinogen, doesn't affect humans in the same sense as we do not rely as heavily on our noses as cats do. In fact, it doesn't even affect all cats.
Finasteride is a drug that belongs to the class of androgen inhibitors, which means that it blocks the production of male sex hormones. It is sold in the United States and Canada under the brand names Proscar and Propecia.
1 Proscar: Finasteride for treatment of an enlarged prostate is taken once a day as a 5-mg tablet. The pill may be crushed or broken if the patient finds it hard to swallow.  Propecia: Finasteride for hair regrowth is taken once a day as a 1-mg tablet. The drug may be taken with or without meals, as the patient prefers.