If you're going to use any injectable gear, then of course you're going to need some "darts." You can pick up syringes at your local pharmacy unless your state has certain restrictions. Also, you can purchase needles online. Just do a little searching around and you'll find several places that'll hook you up. Syringes will run you around 50 cents apiece. Note that it'll be more difficult to obtain needles (at least from the larger, more "legit" companies) if you live in California and Illinois. You'll usually need a doctor's prescription in those states. Still, if you look around enough, you can get what you need.
Drospirenone is 8–10 times more potent as an antimineralocorticoid relative to spironolactone (3 mg drospirenone is equivalent to about 20–25 mg spironolactone in this regard  ).   It is more potent as an antiandrogen relative to spironolactone also but is less potent relative to cyproterone acetate , having about one-third the potency of this drug.   Progestogenic, antimineralocorticoid, and mild antiandrogenic effects have been observed in humans during treatment with drospirenone at a dosage range of to 4 mg per day orally.