Does cytomegalovirus infections have preventative medication that I can use?

Nope. Unless you are immunocompromised, and you can take prophylactic gangiclovir.
Unfortunately not. Cytomegalovirus (CMV) is an infection that can cause flu-like symptoms in healthy individuals. Most of the time, it doesn't require treatment. If you are immune-suppressed or have other health conditions, antiviral agents may shorten the course of illness but will not cure it. There is no prevention for cmv. Once infected, the body develops antibodies to the virus so reinfection cannot occur.