Cialis
(see-A-lis)
A drug used to treat erectile dysfunction. It is also being studied in the treatment of sexual problems in patients treated with radiation or surgery for prostate cancer. Cialis blocks the action of a certain enzyme, which can result in increased blood flow to the penis, causing an erection. It is a type of cGMP phosphodiesterase type 5 (PDE5) inhibitor. Also called tadalafil.