Novirax HC

FDA-Approved Indication

• Recurrent Herpes Labialis (Cold Sores) in immunocompetent adults and adolescents (≥6 years)
• Reduces lesion progression to ulcerative stage
• Decreases time to healing and alleviates symptoms when applied during the prodromal phase (tingling, burning)

Off-Label or Investigational Uses

• No significant off-label indications established.
• Not approved for genital herpes, ophthalmic use, or use in immunocompromised patients.

Available Dosage Form

• Topical Cream: 5% Acyclovir + 1% Hydrocortisone

Adults and Adolescents (≥6 years):

• Apply a thin layer to the affected area on the lips or around the mouth 5 times daily, approximately every 3–4 hours while awake, for 5 consecutive days.
• Treatment should begin at the earliest signs of a cold sore (tingling, redness, itching) to maximize efficacy.

Pediatrics (<6 years):

• Not recommended due to lack of safety and efficacy data.

Administration Notes:

• Apply only to intact skin of the lips and surrounding area; do not apply inside the mouth, nose, eyes, or genitals.
• Wash hands before and after application.
• Do not use with occlusive dressings or cover the area unless instructed.

This fixed-dose combination works through dual mechanisms:

• Acyclovir (5%): A synthetic nucleoside analog activated within HSV-infected cells by viral thymidine kinase. It becomes acyclovir triphosphate, which inhibits viral DNA polymerase, halting DNA replication and viral proliferation. Its selectivity minimizes damage to uninfected cells.
• Hydrocortisone (1%): A low-potency corticosteroid that inhibits pro-inflammatory cytokines, reduces capillary permeability, and suppresses local inflammation, swelling, redness, and pain at the lesion site.

Together, they shorten the duration and reduce severity of cold sores more effectively than acyclovir alone.

• Absorption:
• Systemic absorption of both components is minimal after topical use on intact skin.
• Acyclovir plasma concentrations are typically <0.01 μM after topical application.
• Distribution:
• Primarily local action; no significant systemic distribution.
• Acyclovir may appear in breast milk in trace amounts if absorbed.
• Metabolism:
• Acyclovir: Partially metabolized hepatically if absorbed.
• Hydrocortisone: Hepatic metabolism into inactive metabolites.
• Excretion:
• Acyclovir: Renally (if absorbed)
• Hydrocortisone: Renally after hepatic metabolism
• Half-Life (if systemically absorbed):
• Acyclovir: ~2.5–3 hours
• Hydrocortisone: ~8 hours

• Pregnancy:
• Acyclovir: FDA Category B – No evidence of fetal harm in animal studies.
• Hydrocortisone: Category C – Use topical corticosteroids with caution, especially on large areas or broken skin.
• Use only if clearly needed and benefit outweighs potential risk.
• Lactation:
• Trace amounts of acyclovir and hydrocortisone may appear in breast milk but are considered low risk.
• Avoid application on or near the breast area.

Overall, topical use poses minimal systemic risk in pregnancy and breastfeeding if used correctly.

• Antiviral + Anti-inflammatory Combination
• Acyclovir: Nucleoside analog antiviral (DNA polymerase inhibitor)
• Hydrocortisone: Low-potency corticosteroid (Class VII topical)

• Known hypersensitivity to acyclovir, valacyclovir, hydrocortisone, or any formulation component
• Use on mucosal surfaces (e.g., oral, vaginal, ocular)
• Genital herpes or herpes zoster
• Children under 6 years of age
• Use in immunocompromised patients (not evaluated)

• Avoid ocular use – may cause serious eye irritation
• Not for genital or perianal HSV
• Do not use in immunosuppressed individuals – efficacy and safety not established
• Prolonged use may lead to local steroid side effects: skin thinning, atrophy, or perioral dermatitis
• Risk of secondary infection: due to steroid-induced local immune suppression
• Do not use with occlusive dressings or on broken skin

Discontinue immediately if allergic reaction, worsening skin irritation, or new rash occurs.

Common (≥1%)

• Mild burning or stinging at the application site
• Dryness or flakiness
• Local redness or irritation

Less Common (<1%)

• Itching, rash, swelling
• Allergic contact dermatitis
• Local skin thinning or hypopigmentation (with long-term use)

Rare but Serious

• Secondary bacterial infection
• Hypersensitivity or anaphylaxis (very rare)
• Perioral dermatitis with prolonged or inappropriate use

• Systemic interactions are unlikely due to minimal absorption.
• Avoid concurrent topical corticosteroids or antivirals unless directed by a physician
• No involvement with CYP450 enzyme system

• FDA Approval (Xerese®): First combination of antiviral and corticosteroid for cold sores approved in 2010
• Clinical studies show faster lesion healing, reduced ulcer formation, and lower viral shedding vs. acyclovir alone
• No recent EMA, WHO, or NICE updates as of 2024 specific to this combination
• Not approved for pediatric use under age 6 or for immunocompromised populations

• Store at 20°C to 25°C (68°F to 77°F)
• Protect from light and moisture
• Do not freeze
• Keep tube tightly closed after use
• Discard after expiry or if cream changes in color/consistency