Spermicide contains chemicals such as nonoxynol-9 which is used to immobilize or kill sperm even before it enters the uterus. Spermicide is usually put inside the vagina prior to sexual intercourse. There are handfuls of condoms, vaginal films, foams, sponges and jellies with spermicide are available in the market, both online and at local medical stores. You don't need a doctor's prescription to buy them.
Spermicide is very effective in killing sperms and microorganisms that cause sexually transmitted diseases including HIV. But there is a small issue with Spermicide - it also irritates the cells in the vaginal tract and rectum making them vulnerable to infections. Basically spermicide erodes the cells and an overdose of spermicide can lead to more damage to your vaginal tract and rectum.
According to a study by the World Health Organization, impact of spermicide on vaginal cell wall is dose-related. Meaning, small doses (once a day or less) can cause very little or no disruption to the vaginal cells. But more frequent and larger doses can cause considerable damage. This is the reason why spermicide condoms should not be used more than once a day.
We recommend you not to use a spermicide based condoms as it can lead to pain and discomfort. As you are concerned about unwanted pregnancy prevention, you can use normal condoms as they can be very effective.