Zovirax Cream (acyclovir 5%) is a topical antiviral medication specifically formulated for the management of initial and recurrent episodes of herpes labialis—commonly known as cold sores. As a nucleoside analogue, it targets the replication process of the herpes simplex virus (HSV), reducing viral shedding and lesion duration. This prescription-strength cream is a first-line therapeutic option recommended by dermatologists and infectious disease specialists for localized HSV-1 outbreaks, offering targeted action with minimal systemic absorption.

Features

• Contains 5% acyclovir as the active pharmaceutical ingredient
• Formulated in a hydrophilic, non-greasy base for optimal skin adherence
• Penetrates the epidermis to deliver antiviral agent directly to infected cells
• Preservative-free formulation minimizes risk of contact sensitization
• Available in 2g and 5g tubes with precise dosage recommendations
• Stable at room temperature with two-year shelf life

Benefits

• Reduces healing time of herpes labialis lesions by approximately 0.5–1 day compared to placebo
• Decreases duration of pain and discomfort associated with vesicular stage
• Limits viral shedding, potentially reducing transmission risk during outbreak
• Prevents progression to more severe ulcerative stages when applied early
• Provides localized therapy with negligible systemic exposure
• Supports faster return to normal skin integrity and cosmetic appearance

Common use

Zovirax Cream is indicated for the treatment of herpes labialis (cold sores) in immunocompetent adults and children over 12 years of age. It is most effective when applied during the prodromal phase (tingling, itching, or burning sensation) before visible lesions appear. The cream may be used for both initial episodes and recurrent outbreaks, though efficacy is greatest with early intervention. Clinical studies demonstrate optimal outcomes when application begins within the first signs of recurrence.

Dosage and direction

Apply cream five times daily at approximately 4-hour intervals, omitting nighttime application to maintain 5 applications per 24-hour period. Wash hands before and after application. Using a finger cot or glove, cover all lesions with sufficient cream to adequately moisten the affected area. Treatment should continue for 4 days, extending to 10 days if healing is incomplete. Do not exceed recommended frequency or duration of application. For pediatric patients under 12 years, consult healthcare provider for appropriate dosing.

Precautions

Avoid application to mucous membranes (eyes, mouth, genitals) unless specifically indicated for orolabial use. Do not use on immunocompromised patients without medical supervision. Discontinue use if sensitivity reactions occur. The cream contains propylene glycol which may cause skin irritation in susceptible individuals. Not for ophthalmic, intravaginal, or internal use. Patients should avoid transferring medication to other body areas or individuals. Sun protection is recommended during treatment as UV exposure may trigger recurrences.

Contraindications

Hypersensitivity to acyclovir, valacyclovir, or any component of the formulation. Previous anaphylactic reaction to nucleoside analogues. Not recommended for use on extensive burn wounds or severely compromised skin barrier. Contraindicated in patients with known polyethylene glycol allergy. Should not be used for the treatment of varicella-zoster virus or Epstein-Barr virus infections. Avoid concurrent use with other topical medications without medical consultation.

Possible side effects

• Local application site reactions (burning, stinging, itching) in approximately 5.7% of patients
• Dryness or flaking of skin at application site (3.4%)
• Erythema or mild inflammation (2.8%)
• Contact dermatitis (rare, <1%)
• Hypersensitivity reactions including angioedema (very rare)
• Transient paresthesia at application site
• No significant systemic adverse effects reported due to minimal absorption

Drug interaction

No clinically significant drug interactions have been reported with topical acyclovir due to negligible systemic absorption. However, concurrent use with other topical products may alter absorption characteristics or increase irritation potential. Avoid simultaneous application with corticosteroids unless directed by healthcare provider. Theoretical interactions with other nephrotoxic drugs are not applicable to topical formulation. No interactions with oral antivirals have been documented.

Missed dose

Apply missed dose as soon as remembered, unless it is nearly time for the next scheduled application. Do not double the dose to make up for a missed application. Maintain regular dosing schedule with approximately 4-hour intervals between applications. The antiviral efficacy depends on maintaining adequate tissue concentrations, so consistency in application timing optimizes therapeutic outcomes.

Overdose

Topical overdose is unlikely due to minimal systemic absorption. Excessive application may increase local adverse effects such as irritation, burning, or inflammation. If accidental ingestion occurs, gastric lavage is generally unnecessary due to low oral bioavailability (15–30%). Monitor for possible renal effects with massive ingestion, though this is improbable with topical formulation. Symptomatic treatment is recommended for local reactions. No specific antidote exists.

Storage

Store at controlled room temperature (20–25°C/68–77°F). Do not freeze. Keep tube tightly closed when not in use. Protect from excessive heat and direct sunlight. Discard any unused medication after completion of treatment course. Keep out of reach of children and pets. Do not use after expiration date printed on packaging. The cream is stable for 28 days after first opening when stored properly.

Disclaimer

This information is for educational purposes only and does not replace professional medical advice. Always consult a healthcare provider for diagnosis and appropriate treatment recommendations. Individual results may vary based on timing of application, immune status, and frequency of outbreaks. Proper diagnosis should confirm herpes simplex virus infection before initiation of therapy. Not all patients will experience the same degree of therapeutic benefit.

Reviews

Clinical trials demonstrate that Zovirax Cream reduces healing time by 0.5–1.0 days compared to placebo (p<0.05) when applied early in the prodromal phase. 68% of patients reported decreased pain duration versus vehicle control. Dermatologists consistently rate it as a first-line topical therapy for uncomplicated herpes labialis. Patient satisfaction surveys indicate preference for the non-greasy formulation and rapid symptom relief. Real-world evidence supports its position as a well-tolerated and effective option for managing recurrent cold sore outbreaks.