Aciclovir | Antiviral drug

Available dosage form in the hospital: 5% skin cream, Vial (250 mg), SUSP (200 mg/5ml), 400mg and 800mg tablets.
Class: Acyclovir is an acyclic analogue of 2'-deoxyguanosine.
Antiviral Activity: Acyclovir has activity against herpes-viruses.
Acyclovir has activity against herpes-viruses.




Mechanism of Action:

Acyclovir is converted to its triphosphate form, acyclovir triphosphate (ACV-TP), which competitively inhibits viral DNA polymerase, incorporates into and terminates the growing viral DNA chain, and inactivates the viral DNA polymerase.

Warnings and precautions

Talk to your doctor or pharmacist before taking Aciclovir tablets:
• If you have nervous system abnormalities, please tell your doctor before you start treatment with Aciclovir tablets.
to avoid dehydration, it is important to drink plenty of water whilst taking Aciclovir tablets, especially if you are elderly or taking doses of 4g a day or higher.



• If you have kidney problems.

Other medicines and Aciclovir tablets

Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines:
• Cimetidine (used to treat peptic ulcers) and probenecid (used to treat gout), as these increase the concentration of aciclovir.
• Mycophenolate mofetil (medicine used in transplant patients). Care should be taken if you are taking high doses of Aciclovir, as blood levels of both drugs may increase.
• Cyclosporine (an immuno-suppressant drug). Your doctor may monitor your kidney function.
• Theophylline (used in asthma and other breathing problems).
Zidovudine (used in HIV infection).

Pregnancy and breast-feeding

There is limited information on the use of Aciclovir tablets in pregnancy or breast-feeding. If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.

Driving and using machines
Some side effects such as drowsiness and sleepiness may impair your ability to concentrate and react. Make sure you are not affected before you drive or operate machinery.

Adverse Effects:

Most common with oral acyclovir are light-headedness, headache, diarrhea, nausea, vomiting and abdominal pain. The most common effects associated with parenteral acyclovir are light-headedness and anorexia. The most common adverse effects associated with topical acyclovir are mild pain, burning and stinging.

Dosing

HSV infections of skin and mucous membranes including initial and recurrent genital herpes

Adult: 200 mg po 5 x daily for 5 days
400 mg po 5 x daily or 5 mg/kg IV q8h for 5 days in severely infected or immuno-compromised patients

Initial genital: 400 mg po tid x 7 – 10 days or 200 mg po 5 x daily x 7 – 10 days
Recurrent genital: 400 mg po tid x 5 days or 200 mg po 5 x daily x 5 days or 800 mg po bid x 5 days
Pediatric: Age = 2 years = adult dose | Age below 2 years = half adult dose
Neonates and infants = 20 mg/kg IV q8h for 14 days (21 days for disseminated or CNS infection)

Episodic HSV treatment in HIV-infected patients
Adult: 400 mg po tid x 5 – 10 days or 200 mg 5 times daily for 5 – 10 days | Pediatric: No data

Suppression of recurrent HSV in immuno-competent patients| Adult: 400 mg bid | Pediatric: No data

Prophylaxis of HSV in immuno-compromised patients | Adult: 400 – 800 mg po 2 or 3 times daily 5 mg/kg IV q8h in severely immuno-compromised (i.e. bone marrow transplant) patients or those with impaired absorption from gut | Pediatric: Age = 2 years = adult dose | Age below 2 years = half adult dose

Herpes encephalitis
Adult: 10 mg/kg IV q8h | Pediatric: 500 mg/m2 IV q8h

VZV infections including varicella (chicken pox) and herpes zoster (shingles)
Adult: 800 mg po 5 x daily for 7 days | 10 mg/kg IV q8h in severely immuno-compromised patients or those with impaired absorption from gut (treat for 2 – 7 days or until clinical improvement, followed by po therapy to complete 10 days of total treatment)

Pediatric: Varicella infections:
Age above 6 years = 800 mg po 4 x daily | Age 2 – 5 years = 400 mg po 4 x daily | Age below 2 years = 200 mg po 4 x daily | Continue treatment for 5 days
Alternatively: calculate dosing at 20 mg/kg po (max 800 mg) 4 x daily | IV dose = 250 mg/m2 q8h
Immuno-compromised children = 500 mg/m2 IV q8h | No data on treatment of herpes zoster in immuno-competent children



Reference
https://www.medicines.org.uk/emc/product/4334/smpc
https://www.nhs.uk/medicines/aciclovir/
https://www.webmd.com/drugs/2/drug-941/acyclovir-oral/details
https://www.healthline.com/health/acyclovir-oral-tablet
https://bnf.nice.org.uk/drug/aciclovir.html
https://www.medicinesforchildren.org.uk/aciclovir-oral-viral-infections-0
https://dermnetnz.org/topics/aciclovir/
https://patient.info/medicine/aciclovir-for-viral-infections-zovirax
Aciclovir | Antiviral drug Aciclovir | Antiviral drug Reviewed by gafacom on June 26, 2020 Rating: 5

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