Zovirax Side Effects

Generic name: acyclovir

Medically reviewed by Drugs.com. Last updated on Sep 28, 2024.

Note: This document provides detailed information about Zovirax Side Effects associated with acyclovir. Some dosage forms listed on this page may not apply specifically to the brand name Zovirax.

Applies to acyclovir: buccal mucosa tablet.

Other dosage forms:

• capsule, powder for solution, solution, suspension, tablet

Serious side effects of Zovirax

Along with its needed effects, acyclovir (the active ingredient contained in Zovirax) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking acyclovir:

Less common side effects

• canker sores
• pain in the gums
• sores, ulcers, or white spots on the tongue or inside the mouth

Other side effects of Zovirax

Some side effects of acyclovir may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common side effects

• flushing or redness of the skin
• rash
• unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
• unusually warm skin

For healthcare professionals

Applies to acyclovir: buccal tablet, compounding powder, intravenous powder for injection, intravenous solution, oral capsule, oral suspension, oral tablet.

General adverse events

The more commonly reported adverse reactions include malaise, nausea, vomiting, diarrhea, and headache.^[Ref]

Gastrointestinal

• Common (1% to 10%): Nausea, vomiting, diarrhea, abdominal pain, gingival pain (buccal tablet), aphthous stomatitis (buccal tablet)
• Uncommon (0.1% to 1%): Sore throat
• Postmarketing reports: Gastrointestinal distress^[Ref]

Nausea and vomiting are more frequent in elderly subjects.^[Ref]

Renal

• Rare (0.01% to 0.1%): Elevated blood urea nitrogen, elevated creatinine,
• Very rare (less than 0.01%): Acute renal failure, renal pain
• Frequency not reported: Crystalluria, renal impairment
• Postmarketing reports: Renal failure, hematuria^[Ref]

Renal pain may be associated with renal failure and crystalluria. Renal impairment is generally reversible but may progress to acute renal failure.^[Ref]

Local

• Common (1% to 10%): Application site pain and application site irritation, local inflammation at injection site, phlebitis
• Frequency not reported: Tissue necrosis^[Ref]

Severe local inflammatory reactions, including tissue necrosis, have occurred following infusion into extravascular tissues. Application site pain and application site irritation have occurred with the buccal tablets.^[Ref]

Nervous system

• Common (1% to 10%): Headache, dizziness
• Very rare (less than 0.01%): Ataxia, coma, convulsions, encephalopathy, dysarthria
• Frequency not reported: Giddiness, shaking, taste disturbance, medication taste
• Postmarketing reports: Decreased consciousness, delirium, paresthesia, seizure, tremors^[Ref]

Dizziness, somnolence, and coma more frequent in elderly subjects.^[Ref]

Dermatologic

• Common (1% to 10%): Erythema, rashes (including photosensitivity), pruritus, hives
• Uncommon (0.1% to 1%): Urticaria, accelerated diffuse hair loss
• Frequency not reported: Diaphoresis
• Postmarketing reports: Alopecia, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis^[Ref]

Cardiovascular

• Frequency not reported: Palpitation, chest pain
• Postmarketing reports: Hypotension, peripheral edema^[Ref]

Hematologic

• Very rare (less than 0.01%): Anemia, leukopenia, thrombocytopenia, neutropenia
• Frequency not reported: Hematologic changes including megaloblastic anemia
• Postmarketing reports: Leukocyclastic vasculitis, lymphadenopathy, disseminated intravascular coagulation, hemolysis^[Ref]

Hepatic

• Rare (0.01% to 0.1%): Reversible bilirubin and liver related enzymes
• Very rare (less than 0.01%): Hepatitis, jaundice
• Postmarketing reports: Hyperbilirubinemia^[Ref]

Hypersensitivity

• Rare (0.01% to 0.1%): Anaphylaxis
• Frequency not reported: Angioedema^[Ref]

Ocular

• Frequency not reported: Pars planitis
• Postmarketing reports: Visual abnormalities^[Ref]

Musculoskeletal

• Uncommon (0.1% to 1%): Leg pain
• Postmarketing reports: Myalgia^[Ref]

Other

• Common (1% to 10%): Lethargy, fatigue, fever
• Frequency not reported: Vertigo
• Postmarketing reports: Fever^[Ref]

Genitourinary

• Frequency not reported: Menstrual abnormalities, abnormal urinalysis (characterized by an increase in formed elements in urine sediment) anuria, dysuria, hematuria^[Ref]

Metabolic

• Uncommon (0.1% to 1%): Anorexia
• Frequency not reported: Thirst^[Ref]

Psychiatric

• Very rare (less than 0.01%): Agitation, confusion, hallucinations, psychotic symptoms
• Frequency not reported: Depression, insomnia
• Postmarketing reports: Aggressive behavior^[Ref]

Hallucinations, psychosis, confusion, aggressive behavior, agitation may be more marked in older adults and those with renal impairment.^[Ref]

Respiratory

• Rare (0.01% to 0.1%): Dyspnea^[Ref]

Frequently asked questions

• Can you drink alcohol while taking acyclovir?
• What would be the benefits of taking valacyclovir vs acyclovir?

Further information

Zovirax side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer