Class
- Antiviral Agent
Indications
- Treatment of herpes simplex virus (HSV) infections, including genital and oral herpes
- Prevention of recurrent HSV infections
- Management of varicella-zoster virus (VZV) infections (chickenpox and shingles)
- Prophylaxis in immunocompromised patients to prevent HSV and VZV infections
Mechanism of Action
- Inhibits viral DNA synthesis by incorporating into viral DNA and halting replication
- Selectively targets virus-infected cells, minimizing damage to healthy cells
Dosage and Administration
For Herpes Simplex Virus (HSV)
- Initial outbreak: 200 mg five times daily for 5–10 days (oral)
- Recurrent episodes: 200 mg five times daily for 5 days or 400 mg three times daily for 5 days
- Suppressive therapy: 400 mg twice daily for long-term prevention
For Varicella-Zoster Virus (VZV)
- Shingles: 800 mg five times daily for 7–10 days
- Chickenpox: 800 mg four times daily for 5 days (start within 24 hours of rash onset)
For Immunocompromised Patients
- Dose and duration adjusted based on severity and immune status
Intravenous (IV) Use
- For severe infections or in immunocompromised patients
- Typically dosed at 5–10 mg/kg every 8 hours for 7–10 days
Forms Available
- Tablets: 200 mg, 400 mg, 800 mg
- Oral suspension: 200 mg/5 mL
- Cream: 5% for topical use
- Intravenous solution
Brand Names and Manufacturers
- Zovirax (GSK)
- Generic aciclovir widely available
Cost
- Tablets: $5–$30 for a standard course (generic)
- Cream: $10–$20 per tube (varies by region and brand)
- IV solution: Typically higher cost, often used in hospital settings
Contraindications
- Hypersensitivity to aciclovir, valaciclovir, or any component of the formulation
Precautions
- Adjust dosage in patients with renal impairment to prevent toxicity
- Ensure adequate hydration during treatment to reduce risk of kidney damage
- Use with caution in elderly patients due to increased sensitivity
- Prolonged or repeated use can lead to resistance in certain viral strains
Side Effects
Common
- Nausea, vomiting
- Diarrhea
- Headache
- Fatigue
Less Common
- Rash or skin irritation (topical use)
- Dizziness
- Abdominal pain
Rare but Serious
- Acute kidney injury (due to crystallization in renal tubules)
- Neurological symptoms (e.g., confusion, hallucinations, seizures) in high doses or renal impairment
- Severe allergic reactions (e.g., anaphylaxis)
Drug Interactions
- Probenecid: Increases aciclovir levels, raising toxicity risk
- Cimetidine: May elevate aciclovir plasma concentration
- Nephrotoxic Drugs: Increased risk of kidney damage when combined with other nephrotoxic agents (e.g., aminoglycosides, NSAIDs)
- Valaciclovir: Avoid co-administration as it is converted into aciclovir, potentially leading to overdose
Monitoring Parameters
- Symptom resolution (e.g., reduction in lesions, pain)
- Renal function (especially in patients with renal impairment or on IV therapy)
- Hydration status during high-dose or prolonged therapy
Patient Counseling Points
- Start treatment as soon as symptoms appear for maximum effectiveness
- Take with plenty of water to prevent kidney issues
- For topical cream: Apply to affected areas five times daily; avoid contact with eyes or mucous membranes
- Do not stop treatment early, even if symptoms improve
- Avoid close contact with others during active outbreaks to prevent virus spread
- Store at room temperature and keep away from direct sunlight
FAQs About Aciclovir
Q1: How quickly does aciclovir work?
- Symptoms typically improve within 2–3 days, but full resolution may take up to 10 days.
Q2: Can aciclovir cure herpes?
- No, it manages symptoms and reduces outbreaks but does not eliminate the virus from the body.
Q3: Can aciclovir be used during pregnancy?
- Yes, it is generally considered safe; consult your doctor for personalized advice.
Q4: Can I drink alcohol while taking aciclovir?
- Alcohol does not interact with aciclovir, but moderation is recommended.
Q5: Is it safe for children?
- Yes, aciclovir is approved for use in children for conditions like chickenpox; dosing is based on weight.
Q6: Does aciclovir prevent transmission of herpes?
- It reduces viral shedding but does not completely prevent transmission; use barrier protection during outbreaks.
Q7: What happens if I miss a dose?
- Take it as soon as you remember unless it’s close to the next dose; do not double doses.
Q8: Can I stop aciclovir once symptoms improve?
- Complete the full prescribed course to prevent recurrence or resistance.
Q9: Are there natural alternatives to aciclovir?
- Natural remedies may alleviate symptoms but are not substitutes for antiviral medications.
Q10: Can aciclovir be used long-term?
- Yes, for suppressive therapy, it’s safe for long-term use under medical supervision.
Q11: Does aciclovir work for cold sores?
- Yes, it is effective for treating oral herpes (cold sores) caused by HSV-1.
Q12: Can resistance develop with aciclovir?
- Yes, particularly in immunocompromised patients with prolonged use; alternative antivirals may be needed.
Q13: How should aciclovir cream be applied?
- Wash hands before and after application, and apply to the affected area five times daily until healed.
Q14: Is aciclovir effective for shingles?
- Yes, it reduces the severity and duration of shingles if started early (within 72 hours of rash onset).
Q15: Can I use aciclovir prophylactically?
- Yes, it can be prescribed to prevent recurrent herpes outbreaks in individuals with frequent episodes.