Other brands/names

Acifar, Acyclovir, Azovir, Clinovir, Clopes, Clovika, Danovir, Herax, Herpiclof, Lacyvir, Lovires, Lovirtrop, Matrovir, Mecovir, Mediclovir, Molavir, Palovir, Poviral, Samclovir, Scanovir, Temiral, Viralis, Vireth, Virtaz, Virules, Vircovir, Visirax, Zoter, Zoler, Zovirax.

How It Works

Acyclovir is an antiviral medication used to treat infections caused by the herpes virus, including chickenpox (varicella), shingles (herpes zoster), encephalitis caused by the herpes simplex virus in infants over 6 months of age, and genital herpes (herpes genitalis). The drug works by interacting with specific enzyme molecules in the body, converting into acyclovir triphosphatase. This compound then inhibits the formation and replication of viral DNA, helping to control the infection.

Indications

Acyclovir is used to treat several medical conditions caused by herpes viruses, including Herpes zoster (shingles), genital herpes, and chickenpox (varicella).

Contraindications

Acyclovir should not be used in individuals with a history of hypersensitivity or allergy to acyclovir or other antiviral medications, such as valacyclovir. Symptoms of an allergy may include hives and swelling of the eyelids.

Side Effects

Although side effects are uncommon, some people may experience:

• Nausea

• Vomiting

• Diarrhea

• Stomach aches

• Fatigue

• Fever

• Headache

• Dizziness

• Itching

• Red spots on the skin

• Hives

Types

Acyclovir is available in oral tablet preparations, including 200 mg tablets and 400 mg tablets.

Dosage

Varicella-zoster (chickenpox) or Herpes Zoster (shingles) Virus Infections

Adult dosage:

• 800 mg, 5 times daily, with doses taken approximately every 4 hours for 7 days.

Pediatric dosage:

• Under 2 years old: 200 mg, 4 times daily for 5 days.

• Ages 2–5 years old: 400 mg, 4 times daily for 5 days.

• Ages 6–11 years old: 800 mg, 4 times daily for 5 days.

• Ages 12–17 years old: Same dose as adults (maximum dose 800 mg per day).

Herpes Simplex Infections

Adult dosage:

• 200 mg, 5 times daily, with doses taken every 4 hours for 5–10 days.

Pediatric dosage:

• Under 2 years old: Half of the adult dose.

• Over 2 years old: Same dose as adults.

Safety

Pregnancy:

Acyclovir is classified as FDA Category B, meaning animal studies have not shown any fetal abnormalities, and there are no well-controlled studies in pregnant women. Its use is generally considered safe for pregnant women.

Drug Interactions

Theophylline

Concurrent use of acyclovir with theophylline may increase theophylline levels in the blood, raising the risk of side effects. Therefore, if these drugs are used together, medical supervision is necessary.

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