Everyday Rx · FAQ
What side effects can Cold sore treatment with valacyclovir cause?
Short answer
Cold sore treatment can cause headache, nausea, or stomach pain. Serious reactions are less common but can include kidney problems, confusion, or a severe allergic reaction. Get urgent help for trouble breathing, facial swelling, or a blistering rash. Tell your prescribing physician about kidney disease before taking valacyclovir.
Common side effects of valacyclovir include headache, nausea, and stomach pain. Some people also have vomiting or diarrhea. Contact your pharmacist or prescribing physician if a side effect is bothersome, lasts, or makes it hard to take the medicine as directed. Do not change the dose on your own.
Seek urgent medical care for trouble breathing, swelling of the face or throat, or a painful rash with blisters or peeling skin. New confusion, hallucinations, severe unsteadiness, or seizures also need urgent care. Taking less urine than usual, or having new swelling, can signal a kidney problem and needs prompt medical advice.
Kidney problems and nervous system effects are more likely when the dose is too high for a person’s kidney function. Before treatment, tell your physician about kidney disease, dialysis, dehydration, and all medicines you take. Older adults may need extra caution. Drink fluids as advised, but keep any fluid limits set by your clinician. This is not a complete list of possible side effects.
Sources
Written by the Verra clinical team · Medical review pending
General information, not medical advice. If you're in crisis, call or text 988.
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