Can you drink alcohol while taking valacyclovir?

Can but shouldn't. Although there are no drug-drug (yes, alcohol is a drug) interactions listed, it is always best to avoid mixing medications with alcohol. Alcohol alone is irritating to the stomach and acts as a depressant and affects rational judgment.
Valacyclovir. The company suggest that you should be well hydrated when taking valacyclovir, and use of alcohol, especially heavy use, will cause dehydration.

Related Questions

Is it safe to drink alcohol while taking valacyclovir for oral herpes?

Yes, in moderation. There are no contraindications to drinking alcohol while taking valacyclovir for oral herpes. Contraindications/cautions include: hypersens to drug/class/compon, caution if immunocompormised, advanced hiv, renal impairment, concurrent nephrotoxic agents, elderly, if dehydrated. Getting drunk may not be safe to yourself and/or to others, however. That's why i suggest drinking in "moderation". Read more...
No. You should not have alcohol when treating oral heroes with the medication. It interfere with the effect of the medication. Read more...