Drospirenone, also known as 1,2-dihydrospirorenone, is a steroidal progestin of the spirolactone group used in birth control pills and postmenopausal hormone replacement therapy pills. (from Drugs.com)
Alternatives: According to a 2007 BBC article Fertility Awareness is shown to be 99.6% effective; which beats anything that ever come out of Trojan factory! The Kindara app makes this whole lot easier!
Although, personally I couldn't trust an app alone with a +$250,000, 18 year decision! I recommend using the rhythm method in combination with natural herbal birth control.
Alternative Drugs: Dianette, Mercilon.