Aciclovir: Indication, Dosage, Side Effect, Precaution

Generic Medicine Info Patient Medicine Information

This information is not country-specific. Please refer to the Myanmar prescribing information.

Generic Medicine Info

Indications and Dosage

Buccal
Recurrent herpes labialis

Adult: As mucoadhesive buccal tab: Apply 1 tab (50 mg) as a single dose to the upper gum region within 1 hour of onset of prodromal symptoms and before the appearance of any signs of herpes labialis lesions.

Intravenous
Mucocutaneous herpes simplex in immunocompromised patients

Adult: 5 mg/kg 8 hourly via slow infusion over 1 hour for 5-7 days.
Child: 3 months to 12 years 250 mg/m² 8 hourly via slow IV infusion over 1 hour for 5 days.

Intravenous
First episodes of genital herpes

Adult: 5 mg/kg 8 hourly via slow IV infusion over 1 hour for 7 days.

Intravenous
Herpes simplex encephalitis

Adult: 10 mg/kg 8 hourly via slow IV infusion over 1 hour for 10 days.
Child: 3 months to 12 years 500 mg/m² or 10 mg/kg via slow IV infusion over 1 hour.

Intravenous
Varicella-zoster virus infection

Adult: 5 mg/kg 8 hourly. Immunocompromised patient: 10 mg/kg 8 hourly. Doses to be given via slow IV infusion over 1 hour. Treatment duration: 5-7 days.
Child: 3 months to 12 years 250 mg/m². Immunocompromised patient: 500 mg/m². Doses to be given via slow IV infusion over 1 hour. Treatment duration: 5-7 days.

Intravenous
Neonatal herpes simplex virus infections

Child: 20 mg/kg IV 8 hourly for 14 days for mucocutaneous infections and 21 days for disseminated or CNS disease.

Ophthalmic
Herpes simplex keratitis

Adult: As 3% ointment: Apply 1 cm ribbon of ointment inside the lower conjunctival sac 5 times daily at approx 4-hour intervals. Continue treatment for at least 3 days after healing is complete.
Child: Same as adult dose.

Oral
Varicella-zoster virus infection

Adult: 800 mg 5 times daily at approx 4-hourly intervals, omit night time dose. Treatment duration: 7 days.
Child: ≥2 years 20 mg/kg/dose 4 times daily. Children >40 kg Same as adult dose. Alternative dose: <2 years 200 mg 4 times daily for 5 days; 2-5 years 400 mg 4 times daily for 5 days; 6-11 years 800 mg 4 times daily for 5 days; 12-17 years Same as adult dose. Max: 800 mg daily.

Oral
Primary herpes simplex infections

Adult: 200 mg 5 times daily at approx 4-hourly intervals, omit night time dose. Treatment duration: 5-10 days. Severely immunocompromised patients or patients with impaired absorption: Double the dose to 400 mg; consider IV dosing.
Child: <2 years Half the adult dose; ≥2 years Same as adult dose.

Oral
Suppression of recurrent herpes simplex

Adult: 400 mg bid at approx 12-hourly intervals. Alternatively, 200 mg 4 times daily at approx 6-hourly intervals. Treatment is interrupted every 6-12 months to re-assess recurrence frequency. Consider restarting after 2 or more recurrences. Intermittent therapy: 200 mg 5 times daily at approx 4-hourly intervals for 5 days, preferably initiated during the prodromal period.
Child: 12-17 years Same as adult dose.

Oral
Prophylaxis of herpes simplex in immunocompromised patients

Adult: 200 mg 4 times daily at approx 6-hourly intervals. Severely immunocompromised patients or patients with impaired absorption: Double the dose to 400 mg; consider IV dosing.
Child: <2 years Half the adult dose; ≥2 years Same as adult dose.

Oral
Herpes zoster (shingles)

Adult: 800 mg 5 times daily at approx 4-hourly intervals, omit night time dose. Treatment duration: 7-10 days.
Child: 20 mg/kg/dose 4 times daily. Children >40 kg Same as adult dose. <2 years 200 mg 4 times daily for 5 days; 2-5 years 400 mg 4 times daily for 5 days; 6-11 years 800 mg 4 times daily for 5 days; 12-17 years Same as adult dose.

Topical/Cutaneous
Genital herpes, Herpes labialis

Adult: As 5% cream: Apply 5 times daily at 4-hourly intervals for 4-10 days. As 5% ointment: Apply a sufficient amount to cover all lesions 6 times daily at 3-hourly intervals for 7 days. Start treatment preferably in the prodromal period.
Child: As 5% cream: Same as adult dose.

Renal Impairment

Oral:
Suppression of recurrent herpes simplex; Primary herpes simplex infections:

CrCl (mL/min)	Dosage
<10	200 mg bid at approx 12-hourly intervals.

Herpes zoster (shingles); Varicella-zoster virus infection:

CrCl (mL/min)	Dosage
<10	800 mg bid at approx 12-hourly intervals.
10-25	800 mg tid at approx 8-hourly intervals.

Intravenous:
Patient on peritoneal dialysis: Half the usual dose once daily. Patient on haemodialysis: Half the usual dose once daily then, additional half-dose after haemodialysis.

CrCl (mL/min)	Dosage
<10	Half the usual dose once daily.
10-24	Increase dose interval to 24 hours.
25-50	Increase infusion interval to 12 hours.

Administration

May be taken with or without food. May be taken w/ meals to reduce GI discomfort.

Reconstitution

Intravenous:
Add 10 mL of either sterile water for inj or NaCl 0.89% to provide a solution containing 5 mg/mL. For intravenous infusion, dilute reconstituted powder for inj with compatible IV infusion solution to a final concentration of ≤7 mg/mL.

Incompatibility

Incompatible with foscarnet, ciclosporin, diphenhydramine, gentamicin, granisetron, metoclopramide.

Contraindications

Hypersensitivity to aciclovir and similar antivirals e.g. valaciclovir.

Special Precautions

Immunocompromised patients. Patient receiving high doses. Ensure adequate hydration. Avoid extravasation. Renal impairment. Children. Pregnancy and lactation.

Adverse Reactions

Significant: Contact sensitisation (topical).
Gastrointestinal disorders: Nausea, vomiting, diarrhoea, abdominal pain.
General disorders and administration site conditions: Fatigue, fever.
Investigations: Increased liver enzymes (reversible), BUN and creatinine.
Nervous system disorders: Headache, dizziness.
Skin and subcutaneous tissue disorders: Pruritus, rashes, photosensitivity, urticaria, accelerated diffuse hair loss.
Vascular disorders: Phlebitis (IV).
Potentially Fatal: Thrombotic thrombocytopenic purpura/haemolytic uraemic syndrome (immunocompromised patients). Renal failure.

Pregnancy Category (US FDA)

Buccal/IV/Parenteral/PO/Topical: B

Monitoring Parameters

Monitor urinalysis, BUN, serum creatinine, urine output, liver enzymes, CBC. Assess for neurotoxicity and nephrotoxicity in paediatric patients receiving high doses. Monitor neutrophil count at least twice weekly in neonates.

Overdosage

Symptoms: Oral: Nausea, vomiting, headache and confusion. IV: Elevated serum creatinine and BUN, and subsequent renal failure; neurological effects (e.g. confusion, hallucinations, agitation, seizures and coma). Management: Ensure adequate hydration to prevent crystal formation in the urine. Consider haemodialysis until renal function is restored.

Drug Interactions

Probenecid, cimetidine and mycophenolate mofetil may increase the plasma concentration of aciclovir. May increase the serum concentration of theophylline. May increase risk of renal impairment with nephrotoxic drugs.

Action

Description: Aciclovir is converted to aciclovir monophosphate by virus-specific thymidine kinase then further converted to aciclovir triphosphate by other cellular enzymes. Aciclovir triphosphate competes with deoxyguanosine triphosphate for viral DNA polymerase and incorporates into viral DNA to block DNA synthesis and viral replication.
Pharmacokinetics:
Absorption: Poorly absorbed from the gastrointestinal tract. Penetrates into the skin. Bioavailability: 10-20% (oral).
Distribution: Widely distributed to body tissues including CSF (approx 50% of plasma levels). Crosses the placenta and enters the breast milk. Volume of distribution: 0.7 L/kg. Plasma protein binding: 9-33%.
Metabolism: Converted by viral enzymes to aciclovir monophosphate, and further converted to diphosphate then triphosphate (active form) by cellular enzymes.
Excretion: Via urine (62-91% as unchanged drug and 9-14% as metabolites). Elimination half-life: Approx 2-3 hours.

Chemical Structure

Storage

Oral susp, cap, tab: Store between 15-25°C. Protect from moisture. Powder for inj: Store undiluted vials between 15-25°C. Reconstituted solution is stable for 12 hours at room temperature. Solution for inj: Store between 20-25°C.Topical cream/ointment/Ophthalmic ointment: Store below 25°C.

MIMS Class

Antivirals / Eye Anti-Infectives & Antiseptics / Topical Antivirals

ATC Classification

J05AB01 - aciclovir ; Belongs to the class of nucleosides and nucleotides excluding reverse transcriptase inhibitors. Used in the systemic treatment of viral infections.
D06BB03 - aciclovir ; Belongs to the class of topical antivirals used in the treatment of dermatological diseases.
S01AD03 - aciclovir ; Belongs to the class of antiinfectives, antivirals. Used in the treatment of eye infections.

References

Acyclovir Capsule (Viona Pharmaceuticals Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 04/11/2019.

Acyclovir Injection, Powder, Lyophilized, For Solution (Cadila Healthcare Limited). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 04/11/2019.

Acyclovir Ointment (G&W Laboratories, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 04/11/2019.

Acyclovir Sodium Injection, Solution (Fresenius Kabi USA, LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 04/11/2019.

Anon. Acyclovir (Systemic). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 04/11/2019.

Anon. Acyclovir (Topical). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 04/11/2019.

Buckingham R (ed). Aciclovir. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 04/11/2019.

Joint Formulary Committee. Aciclovir. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 04/11/2019.

Sitavig Tablet, Delayed Release (EPI Health, Inc). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 06/11/2019.

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