Is there medicine that can suppress/prevent cold sores from herpes?

Cold sore med: Yes Valtrex (valacyclovir) (and others) is an antiviral pill that if taken at the first hint (tingle or hotness, etc) can abort or reduce an attack. The treatment only takes one day ! see your doctor for an rx there are also creams that help but not as well as the pills.

Yes, both Rx & OTC: There are both prescription anti-virals (acyclovir and valtrex) and otc lysine which can suppress the recurrence of herpetic cold sores or reduce their severity and/or frequency of occurrence.

Acyclovir: While Acyclovir (zovirax) and valacyclovir (valtrex) are both good for preventing hsv cold sores, i typically prefer acyclovir. I've had good success using it with patients and it's a good bit less expensive than valtrex, so that makes it a bit easier on patients without prescription drug coverage on their insurance.