What do systematic reviews say?

Intervention not reported

It is very uncertain whether the intervention changes adverse effects ‐ Vomiting (very low certainty).

• Valacyclovir versus acyclovir for the treatment of herpes zoster ophthalmicus in immunocompetent patients 2016 · Cochrane Headline outcomes only
  RR 1.45 [0.25, 8.32]
  1 study · 110 participants
  Very low