How to use Acyclovir (Zovirax)

Aciclovir is a drug with antiviral action, available in tablets, cream, injectable or ophthalmic ointment, which is indicated for the treatment of infections caused by Herpes zoster , Varicella zoster , infections of the skin and mucous membranes caused by the Herpes simplex virus ,  treatment of meningoencephalitis herpetic and infections caused by cytomegalovirus.

This medicine can be bought in pharmacies for a price of about 12 to 228 reais, depending on the pharmaceutical form, packaging size and brand, since the person can choose a generic or the brand Zovirax. To buy this medicine, a prescription is required.

How to use

1. Pills

The dosage must be established by the doctor, according to the problem to be treated:

  • Treatment of Herpes simplex in adults : The recommended dose is 1 tablet of 200 mg, 5 times a day, with intervals of approximately 4 hours, skipping the night dose. Treatment must be continued for 5 days, and must be extended to severe initial infections. In severely immunocompromised patients or those with problems with intestinal absorption, the dose can be doubled to 400 mg or considered intravenous medication.
  • Suppression of Herpes simplex in immunocompetent adults : The recommended dose is 1 tablet of 200 mg, 4 times a day, at intervals of approximately 6 hours or 400 mg, 2 times a day, at intervals of approximately 12 hours. A dose reduction to 200 mg, 3 times a day, at approximately 8 hour intervals, or up to 2 times a day, at approximately 12 hour intervals, may be effective.
  • Prevention of Herpes simplex in  immunocompromised adults : 1 tablet of 200 mg is recommended, 4 times a day, at intervals of approximately 6 hours. For seriously immunocompromised patients or those with intestinal absorption problems, the dose can be doubled to 400 mg or, alternatively, administration of intravenous doses is considered.
  • Treatment of Herpes zoster in adults: The recommended dose is 800 mg, 5 times a day, at intervals of approximately 4 hours, skipping the night doses, for 7 days. In patients who are severely immunocompromised or have problems with intestinal absorption, administration of intravenous doses should be considered. Administration of doses should be started as soon as possible after the onset of infection. 
  • Treatment in seriously immunocompromised patients : The recommended dose is 800 mg, 4 times a day, at approximately 6 hour intervals.

In infants, children and the elderly, the dosage should be adjusted according to the person’s weight and health.

2. Creme

The cream is adapted for the treatment of skin infections caused by the Herpes simplex virus , including genital and labial herpes. The recommended dose is one application, 5 times a day, at intervals of about 4 hours, skipping the application at night.

Treatment should continue for at least 4 days, for cold sores, and for 5 days, for genital herpes. If healing does not occur, treatment should be continued for another 5 days and if the lesions remain after 10 days, consult a doctor.

3. Ophthalmic ointment

Acyclovir eye ointment is indicated for the treatment of keratitis, an inflammation of the cornea caused by infection with the herpes simplex virus. 

Before using this ointment, you should wash your hands thoroughly and apply about 5 times a day to the affected eye, at intervals of approximately 4 hours. After healing is observed, the product should be continued for at least another 3 days.

How acyclovir works

Acyclovir is an active substance that works by blocking the multiplication mechanisms of the Herpes simplex virus , Varicella zoster, Esptein Barr and Cytomegalovirus preventing them from multiplying and infecting new cells.

Who should not use

Acyclovir should not be used by people who are allergic to any of the components of the formula. In addition, it is also not recommended in women who are pregnant or intend to become pregnant and breastfeeding, unless directed by the doctor.

Contact lenses should not be worn during treatment with acyclovir ophthalmic ointment.

Possible side effects

Some of the most common side effects that may occur during treatment with acyclovir tablets are headache, dizziness, nausea, vomiting, diarrhea and pain in the abdomen, itching and redness, bumps on the skin that can get worse with exposure to the sun, feeling of tiredness and fever.

In some cases, the cream can cause temporary burning or burning, mild dryness, flaking of the skin and itching.

Ophthalmic ointment can lead to the appearance of lesions on the cornea, mild and transient stinging sensation after the application of the ointment, local irritation and conjunctivitis.

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