Tazzle 10 mg is a drug that is used to treat erectile dysfunction in men. It belongs to a class of drugs called phosphodiesterase type 5 inhibitors. Phosphodiesterase type 5 is an enzyme that is responsible for the breakdown of cGMP in the body. cGMP is a substance that is produced in the body during sexual arousal and it helps to relax the blood vessels in the penis, so that blood can flow into the penis and cause an erection.