Zovirax (acyclovir) is an antiviral drug. It slows the growth and spread of the herpes virus in the body. Acyclovir will not cure herpes, but it can lessen the symptoms of the infection.

Zovirax is used to treat infections caused by herpes viruses, such as genital herpes, cold sores, shingles and chicken pox.

Zovirax is best used as soon as possible after the signs and symptoms of herpes infection (for example,pain, burning, or blisters) begin to appear.

Take Zovirax for the entire length of time prescribed by your doctor. Your symptoms may get better before the infection is completely treated.

Herpes infections are contagious and you can infect other people, even while you are being treated with Zovirax. Avoid letting infected areas come into contact with other people. Avoid touching an infected area and then touching your eyes. Wash your hands frequently to prevent passing the infection to others.

Take Zovirax exactly as it was prescribed for you. Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Treatment with Zovirax should be started as soon as possible after the first appearance of symptoms (such as tingling, burning, blisters).

Tell your doctor if you have any changes in weight. Zovirax doses are based on weight (especially in children and teenagers), and any changes may affect the dose.

Drink plenty of water while you are taking Zovirax to keep your kidneys working properly.

Lesions caused by herpes viruses should be kept as clean and dry as possible. Wearing loose clothing may help to prevent irritation of the lesions.

Use this medicine for the full prescribed length of time. Your symptoms may improve before the infection is completely treated. Zovirax will not treat a viral infection such as the flu or a common cold.

Dosage adjustment is recommended when administering Zovirax to patients with renal impairment.

Patients are instructed to consult with their physician if they experience severe or troublesome adverse reactions, they become pregnant or intend to become pregnant, they intend to breastfeed while taking orally administered Zovirax, or they have any other questions.

Patients should be informed that Zovirax is not a cure for genital herpes. There are no data evaluating whether Zovirax will prevent transmission of infection to others. 

The areas affected by herpes should be kept as clean and dry as possible. Also, wear loose-fitting clothing to avoid irritating the sores (blisters).

If your symptoms do not improve within 1 week, or if they become worse, check with your doctor.

Check with your doctor immediately if any of the following side effects occur while taking acyclovir:

• Abdominal or stomach pain
• decreased frequency of urination or amount of urine
• increased thirst
• loss of appetite
• unusual tiredness or weakness

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
-kidney disease
-an unusual or allergic reaction to acyclovir, ganciclovir, valacyclovir, other medicines, foods, dyes, or preservatives
-pregnant or trying to get pregnant
-breast-feeding

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

Where should I keep my medicine?

Keep out of the reach of children.

Store at room temperature between 15 and 25 degrees C (59 and 77 degrees F). Throw away any unused medicine after the expiration date.