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acyclovir (injection)

Pronunciation: a SYE klo veer

Brand: Zovirax

What is the most important information I should know about acyclovir injection?

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

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

Herpes infections are contagious and you can infect other people, even while you are being treated with acyclovir. 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.

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Acyclovir will not prevent the spread of genital herpes. Avoid sexual intercourse or use a latex condom to prevent spreading the virus to others.

What is acyclovir?

Acyclovir is an antiviral drug. It slows the growth and spread of the herpes virus so that the body can fight off the infection. Acyclovir will not cure herpes, but it can lessen the symptoms of the infection.

Acyclovir injection is used to treat severe infections caused by herpes viruses, including severe forms of genital herpes, shingles, herpes encephalitis (swelling of the brain), and herpes infections in people with other diseases that weaken the immune system.

Acyclovir may also be used for other purposes not listed in this medication guide.

What should I discuss with my healthcare provider before using acyclovir injection?

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You should not use this medication if you are allergic to acyclovir or valacyclovir (Valtrex).

If you have any of these other conditions, you may need an acyclovir dose adjustment or special tests:

  • kidney disease (or if you are on dialysis);
  • liver disease;
  • a brain or nervous system disorder such as Parkinson's disease, schizophrenia, or tardive dyskinesia; or
  • an electrolyte imbalance (such as high or low levels of calcium, sodium, or potassium in your blood).

FDA pregnancy category B. This medication is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. Herpes virus can be passed from an infected mother to her baby during childbirth. If you have genital herpes, it is very important to prevent herpes lesions during your pregnancy so that you do not have a genital lesion when your baby is born.

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Acyclovir can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

How should I use acyclovir injection?

Use exactly as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.

Acyclovir is injected into a vein through an IV. You may be shown how to use an IV at home. Do not self-inject this medicine if you do not fully understand how to give the injection and properly dispose of used needles, IV tubing, and other items used to inject the medicine.

Acyclovir must be given slowly, and the IV infusion can take at least 1 hour to complete.

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

Use a disposable needle only once. Throw away used needles in a puncture-proof container (ask your pharmacist where you can get one and how to dispose of it). Keep this container out of the reach of children and pets.

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Drink plenty of liquids while you are using acyclovir to keep your kidneys working properly.

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

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.

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Store acyclovir injection at room temperature away from moisture and heat.

What happens if I miss a dose?

Use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

What happens if I overdose?

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Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include agitation, seizure (convulsions), hallucinations, and urinating less than usual or not at all.

What should I avoid while using acyclovir injection?

Herpes infections are contagious and you can infect other people, even while you are being treated with acyclovir. 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.

Multum emt

Acyclovir will not prevent the spread of genital herpes. Avoid sexual intercourse or use a latex condom to prevent spreading the virus to others.

What are the possible side effects of acyclovir injection?

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Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

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Stop using acyclovir and call your doctor at once if you have a serious side effect such as:

  • urinating less than usual or not at all;
  • fever, chills, body aches, flu symptoms;
  • a red, blistering, peeling skin rash;
  • jaundice (yellowing of the skin or eyes);
  • swelling, pain, tenderness, or skin changes where the injection was given;
  • pale skin, easy bruising or bleeding, weakness; or
  • confusion, tremors, agitation, tiredness, hallucinations, or seizure (convulsions).

Less serious side effects may include:

  • nausea, vomiting, diarrhea, stomach pain, loss of appetite;
  • muscle pain, numbness or tingling;
  • loss of coordination;
  • drowsiness;
  • headache, feeling light-headed; or
  • swelling in your hands or feet.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect acyclovir injection?

Before using acyclovir, tell your doctor if you are also taking probenecid (Benemid). If you are using probenecid, you may need a dose adjustment or special tests during treatment with acyclovir.

There may be other drugs that can interact with acyclovir. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

Where can I get more information?

Your pharmacist can provide more information about acyclovir injection.


Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

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