If you are taking VALTREX to treat cold sores, chickenpox, shingles, or genital herpes, you should start treatment as soon as possible after your symptoms start. The medication may not work as well if you wait more than 72 hours to start it. Make halpojen geneeristen valacyclovir the suspension to volume 100 mL with SSV and shake thoroughly to mix. Also, elderly patients are more likely to have kidney problems. There may be other drugs that can interact with valacyclovir. You should also limit your alcohol intake, because it might just aggravate this particular side effect.