Virux 400 mg

Description

Indications

Aciclovir is used for the treatment and prevention of infections caused by Herpes simplex virus (types I & II) and Varicella zoster virus (which causes herpes zoster and chickenpox). Specifically, it is indicated for:

• Treatment of Herpes simplex virus infections of the skin and mucous membranes, including initial and recurrent genital herpes and herpes labialis (cold sores).
• Prevention of Herpes simplex virus infections in immunocompromised patients.

Always take this medication as prescribed by a registered healthcare professional.

Pharmacology

Aciclovir is a synthetic purine analogue that works by inhibiting the replication of viruses. It exerts its antiviral effect on Herpes simplex and Varicella-zoster viruses by interfering with viral DNA synthesis. In infected cells, Aciclovir is converted into its active form, Aciclovir Triphosphate, through several phosphorylation steps. This active form blocks viral DNA synthesis, thus inhibiting viral replication.

Approximately 15-30% of an oral dose of Aciclovir is absorbed from the gastrointestinal tract, with peak plasma concentrations occurring within 1.5 to 2 hours after oral administration. Aciclovir is widely distributed throughout the body, including tissues such as the brain, saliva, lungs, liver, muscle, spleen, uterus, vaginal mucosa, cerebrospinal fluid (CSF), and herpetic vesicular fluid. The drug is excreted through the kidneys via glomerular filtration and tubular secretion.

Dosage & Administration

For Herpes Simplex Virus Infections (Initial Episodes)

• Adults: 200 mg five times a day, usually for 5 days.

For Immunocompromised Patients (Herpes Simplex)

• Adults: 400 mg five times a day for 5 days (may extend if new lesions appear or healing is incomplete; increase to 800 mg five times daily for genital herpes in immunocompromised patients).
• Children under 2 years: Half of the adult dose.
• Children over 2 years: Full adult dose.

For Prevention of Recurrence of Herpes Simplex

• Adults: 200 mg four times a day or 400 mg twice daily (can reduce to 200 mg 2 or 3 times daily and interrupt every 6-12 months).
• Children under 2 years: Half of the adult dose.
• Children over 2 years: Full adult dose.

For Prophylactic Treatment in Immunocompromised Patients

• Adults: 200 to 400 mg four times daily.
• Children under 2 years: Half of the adult dose.
• Children over 2 years: Full adult dose.

For Chickenpox (Varicella)

• Adults & children over 40 kg: 800 mg four times daily for 5 days.
• Children under 40 kg: 20 mg/kg (maximum 800 mg) per dose, orally 4 times daily (80 mg/kg/day) for 5 days.
• Children 1 month-2 years: 200 mg four times daily for 5 days.
• Children 2-5 years: 400 mg four times daily for 5 days.
• Children 6-12 years: 800 mg four times daily for 5 days.

For Herpes Zoster (Shingles)

• Adults & children over 2 years: 800 mg five times daily for 7 days.

For Initial Rectal (Proctitis) Herpes Infections

• Adults: 400 mg five times daily for 10 days, or until clinical resolution occurs.

Renal Impairment
For patients with severe renal impairment, dosage adjustments are recommended.

Always follow the guidance of a registered healthcare professional for proper dosage and duration of treatment.

Interaction

Co-administration of Aciclovir with Probenecid may reduce its excretion, leading to increased plasma concentrations and a potential risk of toxicity.

Contraindications

Aciclovir is contraindicated in patients with a known hypersensitivity to the drug.

Side Effects

Possible side effects of Aciclovir may include:

• Rash
• Gastrointestinal disturbances (e.g., nausea, vomiting)
• Elevated bilirubin and liver enzymes
• Increased blood urea and creatinine
• Decreased blood cell counts (e.g., red and white blood cells)
• Headache
• Neurological reactions (e.g., dizziness, confusion)
• Fatigue

Pregnancy & Lactation

Aciclovir is classified as Pregnancy Category B. It should only be used during pregnancy if the potential benefits justify the possible risks to the fetus. Caution is advised when administering Aciclovir to nursing mothers.

Precautions & Warnings

Aciclovir should be used with caution in patients with renal impairment. Dosage should be adjusted based on creatinine clearance. Additionally, it is recommended to monitor neutrophil counts at least twice weekly in neonates receiving Aciclovir.

Therapeutic Class

Aciclovir is classified under Herpes simplex and Varicella-zoster virus infections.

Storage Conditions

Store below 25°C. Keep the medication protected from light and moisture, and out of reach of children.