What side effects should I be expecting from taking Zovirax?

Signs of Zovirax (acyclovir) allergy: difficulty breathing, hives (rash on your body), swelling of the face, lips, tongue, or throat—If you experience any of these symptoms, please call 911 or seek emergency medical care at the nearest emergency room (ER).

Call your doctor immediately if you experience any of the following signs:

• Signs of an acute kidney injury — painful or difficult urination, decreased urine amount to little or none, feeling tired, shortness of breath, swelling in your feet or ankles.
• Renal pain, or kidney pain, as this can be associated with acute renal failure or kidney stones 
• Changes in behavior
• Aggression
• Confusion, hallucinations, delirium
• Unusual bruising or bleeding, purple or red pinpoint spots under your skin

Common side effects of Zovirax:

• Nausea, vomiting, diarrhea
• Headache
• Malaise (feeling unwell)
• Mild skin pain
• Rash, itching

Zovirax Overdose: Go to the nearest emergency room for immediate medical attention or call the Poison Control Center at 1-800-222-1222. You can find more information at your local poison control center or at www.poisonhelp.org/help.

Overdosage of Zovirax can cause acute renal failure, which typically presents with an elevation of serum creatinine and blood urea nitrogen that may require hemodialysis.  

Overdosage of Zovirax can cause acute renal failure, which typically presents with an elevation of serum creatinine and blood urea nitrogen. Sometimes, Zovirax overdosed victims may require hemodialysis to remove toxins from their bodies. 

This risk is higher in those with existing renal impairment. 

Seek medical care immediately if you have any of the following serious symptoms as they can be signs of severe Zovirax toxicity: 

• Agitation
• Coma
• Lethargy
• Seizures

The above list on this site may not include all the possible side effects of Zovirax. Speak to your doctor or pharmacist at your local pharmacy if you have persistent side effects or any side effects that are not listed above. You can also report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088.

Source: FDA