Aciclovir is a nucleoside analogue antiviral medication specifically designed to manage infections caused by the herpes simplex virus (HSV) and varicella-zoster virus (VZV). It functions by inhibiting viral DNA replication, thereby reducing the severity and duration of outbreaks. Available in oral, topical, and intravenous formulations, aciclovir is a first-line therapeutic option prescribed globally for its efficacy and well-established safety profile. This product card provides a comprehensive overview for healthcare professionals and informed patients.

Features

• Active ingredient: Aciclovir (chemical name: 9-[(2-hydroxyethoxy)methyl]guanine)
• Available formulations: tablets (200mg, 400mg, 800mg), cream (5%), ointment (5%), intravenous infusion
• Mechanism of action: selective inhibition of viral DNA polymerase
• Bioavailability: approximately 15–30% (oral); minimal systemic absorption (topical)
• Half-life: 2–3 hours in adults with normal renal function
• Excretion: primarily renal (unchanged drug and metabolites)

Benefits

• Reduces healing time and pain associated with herpes simplex outbreaks
• Decreases the frequency of recurrent genital herpes episodes
• Lowers risk of viral transmission to sexual partners when used suppressively
• Effective in treating herpes zoster (shingles), minimizing postherpetic neuralgia risk
• Used prophylactically in immunocompromised patients to prevent HSV reactivation
• Well-tolerated with a low incidence of serious adverse effects

Common use

Aciclovir is indicated for the treatment of initial and recurrent episodes of herpes simplex virus infections (genital herpes, labial herpes, herpetic whitlow), herpes zoster (shingles), and chickenpox (varicella). It is also used as suppressive therapy to prevent recurrent herpes outbreaks and for prophylaxis in immunocompromised individuals (e.g., HIV patients, transplant recipients). Off-label uses may include herpes encephalitis, eczema herpeticum, and herpetic keratitis, though these typically require specialist supervision.

Dosage and direction

Dosage varies based on indication, patient immune status, and renal function. For immunocompetent adults:

• Genital herpes (initial): 200mg orally 5 times daily for 10 days, or 400mg TID for 7–10 days
• Recurrent genital herpes: 200mg 5 times daily for 5 days, or 800mg TID for 2 days
• Suppressive therapy: 400mg BID or 200mg 2–5 times daily
• Herpes zoster: 800mg orally 5 times daily for 7–10 days
• Chickenpox: 800mg 4 times daily for 5 days (initiated within 24 hours of rash onset)

Topical formulations should be applied 5–6 times daily for up to 10 days. Intravenous dosing is weight-based and reserved for severe infections or immunocompromised patients. Dosage adjustment is necessary in renal impairment.

Precautions

Hydration should be maintained during treatment to prevent crystalluria. Use with caution in elderly patients, those with renal impairment, or neurological abnormalities. Monitor renal function during intravenous therapy. Topical aciclovir should not be applied to mucous membranes or eyes. Pregnancy Category B; use only if potential benefit justifies potential risk. Not recommended during breastfeeding unless essential.

Contraindications

Hypersensitivity to aciclovir, valaciclovir, or any component of the formulation. Intravenous administration is contraindicated in patients with known renal impairment unless benefits outweigh risks and appropriate dose adjustments are made.

Possible side effect

Common side effects include nausea, vomiting, diarrhea, headache, and dizziness. Topical application may cause mild pain, burning, or itching. Rare but serious adverse effects include:

• Acute renal failure (especially with IV use or dehydration)
• Neurotoxicity (agitation, confusion, hallucinations, tremors)
• Hematologic abnormalities (thrombocytopenia, leukopenia)
• Hepatotoxicity
• Allergic reactions (rash, anaphylaxis in rare cases)

Drug interaction

Probenecid may increase aciclovir plasma concentrations. Concurrent use with other nephrotoxic drugs (e.g., aminoglycosides, cyclosporine) may enhance renal toxicity. Potential additive effects with other CNS-acting drugs.

Missed dose

If a dose is missed, take it as soon as remembered unless it is nearly time for the next dose. Do not double the dose. Consistent dosing is important for efficacy, especially in suppressive therapy.

Overdose

Symptoms may include agitation, coma, seizures, and renal impairment. Management includes supportive care and hydration. Hemodialysis significantly enhances aciclovir removal and is recommended in severe overdose, especially with renal involvement.

Storage

Store at room temperature (15–30°C). Protect from moisture and light. Keep out of reach of children. Do not use beyond the expiration date. Intravenous solutions should be used immediately after reconstitution.

Disclaimer

This information is intended for medical professionals and informed patients and should not replace professional medical advice, diagnosis, or treatment. Always consult a healthcare provider for personalized recommendations and to address any health concerns or potential side effects.

Reviews

Clinical studies and meta-analyses consistently demonstrate aciclovir’s efficacy in reducing outbreak duration and frequency. A 2021 systematic review confirmed its role as a first-line treatment for herpes simplex and zoster infections, with a favorable safety profile. Patient reports often highlight reduced symptom severity and improved quality of life, particularly with long-term suppressive use. Some note gastrointestinal discomfort as a temporary drawback.