Does Viagra (Sildenafil) prevent pregnancy or the spread of Sexually Transmitted Diseases?
Definitely it is not! You can buy viagra overnight delivery for better erection, but it does not stop the spread of HIV or other sexually transmitted diseases (STDs) to others through sexual contact.
If you want to avoid pregnancy, make sure to use an effective form of contraception. I would personally recommend using condoms + another form of birth control like the pills.