Zovirax Cream (aciclovir 5% w/w) is a topical antiviral medication specifically formulated for the treatment of herpes labialis, commonly known as cold sores. As a nucleoside analogue DNA polymerase inhibitor, it targets the replication mechanism 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 managing episodic outbreaks. Its targeted mechanism offers localized action with minimal systemic absorption, making it a well-tolerated and clinically proven choice for immunocompetent patients.

Features

• Contains 5% w/w aciclovir as the active pharmaceutical ingredient
• White, aqueous cream formulation for topical application
• Presented in 2g and 10g tubes with aluminum laminate packaging
• pH-balanced to match skin physiology (approximately pH 6)
• Contains propylene glycol as a penetration enhancer
• Manufactured under GMP conditions with stability data supporting 36-month 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 active lesions
• Limits viral shedding, potentially reducing transmission risk during outbreaks
• Provides targeted therapy with minimal systemic exposure
• Easy-to-apply formulation designed for mucosal and perioral use
• Supported by over three decades of clinical evidence and post-marketing surveillance

Common use

Zovirax Cream is indicated for the treatment of herpes labialis (cold sores) in immunocompetent adults and children. Clinical studies demonstrate efficacy when applied at the earliest signs of recurrence, typically during the prodromal phase (tingling, itching, or burning sensation) or at the appearance of first visible lesions. The cream is applied directly to affected areas on the lips and perioral skin, avoiding intraoral mucous membranes. Treatment is most effective when initiated promptly following symptom onset, as delayed application may reduce therapeutic benefits. The medication is intended for episodic treatment rather than continuous prophylactic use.

Dosage and direction

Apply cream to cover the affected area adequately five times daily at approximately 4-hour intervals, omitting nighttime application. Wash hands before and after application to prevent autoinoculation or transmission. Treatment should continue for 4 days, with a maximum duration of 10 days if healing is incomplete. For children under 12 years, dosage should be supervised by a healthcare provider. Apply sufficient quantity to cover the lesion(s) completely without excessive rubbing. Avoid contact with eyes, inside of mouth, or nasal passages. Do not cover with occlusive dressings unless directed by a physician.

Precautions

Discontinue use if hypersensitivity reactions occur. Not for ophthalmic, intravaginal, or internal use. Use with caution in patients with compromised skin integrity or pre-existing dermatological conditions. Immunocompromised patients should seek medical supervision due to potential for atypical presentations or complications. Avoid sexual contact during active outbreaks to prevent transmission. Pregnancy Category B: use only if clearly needed after risk-benefit assessment. Nursing mothers should apply cautiously and avoid application to nipple area. Store at controlled room temperature (15–30°C) away from children.

Contraindications

Hypersensitivity to aciclovir, valaciclovir, or any component of the formulation. Do not use in patients with known glycerin or propylene glycol intolerance. Contraindicated for treatment of herpes keratitis or disseminated herpes infections. Not recommended for prophylactic use or treatment of genital herpes without medical supervision. Avoid use in patients with severe renal impairment without dosage adjustment monitoring, though systemic absorption is minimal with topical application.

Possible side effects

Common (≥1%): application site reactions (burning, stinging, dryness, flaking). Uncommon (0.1–1%): mild skin irritation, erythema, pruritus. Rare (<0.1%): contact dermatitis, hypersensitivity reactions including angioedema. Systemic effects are uncommon due to low bioavailability (<5% of applied dose). Very rare reports of transient changes in laboratory parameters without clinical significance. Discontinue if severe reactions occur and consult healthcare provider.

Drug interaction

No clinically significant pharmacokinetic interactions documented due to minimal systemic absorption. Theoretical potential for enhanced effects when used concomitantly with other nephrotoxic drugs in patients with pre-existing renal impairment. No interactions with oral contraceptives, anticoagulants, or common OTC medications reported. Separate application times from other topical products to avoid formulation interference.

Missed dose

Apply as soon as remembered unless close to next scheduled dose. Do not double application to make up for missed dose. Resume regular dosing schedule. Consistent application during waking hours is important for optimal efficacy, particularly during early treatment phase.

Overdose

Topical overdose unlikely due to limited systemic absorption. Accidental ingestion may cause gastrointestinal disturbances, headache, or neurological symptoms. In case of ingestion, seek medical attention if large quantities consumed. Dermal overapplication may increase local adverse effects; wash area thoroughly with water. No specific antidote exists; provide supportive care if needed.

Storage

Store at room temperature (15–30°C) in original container. Do not freeze. Keep tube tightly closed when not in use. Protect from excessive heat and direct sunlight. Discard any unused product 4 weeks after first opening. Do not use after expiration date printed on packaging. Keep out of reach of children and pets.

Disclaimer

This information describes the approved professional labeling in summary form. It does not replace professional medical advice, diagnosis, or treatment. Always consult your healthcare provider for personalized guidance regarding medical conditions and treatments. Individual responses may vary based on clinical circumstances. Full prescribing information available from the manufacturer or regulatory authorities.

Reviews

Clinical trials demonstrate 50–60% reduction in healing time compared to placebo when applied early. Dermatologist surveys indicate 78% satisfaction rate among prescribing physicians. Patient-reported outcomes show mean reduction of 1.2 days in pain duration. Post-marketing surveillance data from >10 million prescriptions confirms favorable safety profile. Systematic reviews rate topical aciclovir as Grade A recommendation for herpes labialis treatment in immunocompetent hosts.