Brand Names

Zovirax ® (There may be other brand names for this medication)

How is it Administered?

Your medicine may be given intravenously, which means it will be given through a tube placed in a vein, usually in your arm, wrist, hand or chest. Acyclovir may also be taken by mouth as a capsule or liquid or used topically as a cream.

What is it Used For?

Acyclovir belongs to the family of medicines called antivirals. Antivirals are used to treat infections caused by viruses. Usually they work for only one kind of virus.

What Should I Tell My Doctor Before I Begin Receiving Acyclovir?

Tell your doctor if you:

  • have had an allergic reaction to acyclovir or valacyclovir. Also tell your health care professional if you are allergic to any other substances, such as foods, sulfites or other preservatives, or dyes
  • are pregnant or breastfeeding
  • have kidney disease, dehydration, or nervous system problems
  • are taking any of the following medications:


  • carmustine (BiCNU)
  • cisplatin (Platinol)
  • combination pain medicine containing acetaminophen and aspirin
  • cyclosporine (Sandimmune)
  • deferoxamine (Desferal) (with long-term use)
  • gold salts (medicine for arthritis)
  • inflammation or pain medicine, except narcotics
  • lithium ( Lithane)
  • methotrexate (Mexate)
  • other medicine for infection
  • penicillamine (Cuprimine)
  • plicamycin (Mithracin)
  • streptozocin (Zanosar) or tiopronin (Thiola)

This drug may interact with other medications, increasing or decreasing their effectiveness or causing harmful side effects. Tell your doctor and pharmacist about any prescription or over-the- counter medications, vitamins, herbal or diet supplements that you are taking.

What Are Some Possible Side Effects I May Experience?

  • Pain, swelling, bruising, or redness at place of injection
  • Abdominal or stomach pain, nausea or vomiting, loss of appetite, diarrhea
  • Decreased frequency of urination or amount of urine. Increased thirst
  • General feeling of discomfort or illness, unusual tiredness or weakness
  • Headache, confusion, sense of agitation or uneasiness, drowsiness
  • Skin: blistering, peeling, itching or loosening of skin; rash; swelling of hands, legs, feet, or sex organs; bluish coloring, especially of the hands and feet
  • Changes in vision, red or irritated eyes
  • Coughing, difficulty in breathing or swallowing
  • Fast heartbeat, dizziness or feeling faint
  • Mood or mental changes, irritability
  • Muscle cramps, clumsiness, trembling, unsteadiness
  • Painful, or tender lymph nodes

How Can I Manage These Side Effects?

  • Ask your doctor about medication to help prevent or lessen nausea, vomiting, and diarrhea.
  • Mouth care is very important while taking this drug. Rinse your mouth with a mixture of 1⁄2 tsp of baking soda in 8 oz of water after every meal and at bedtime. Brush your teeth and gums often with soft toothbrush. (Soften it further by running it under warm water before brushing.)
  • Avoid mouthwashes that contain alcohol. Avoid alcohol and smoking.
  • If you develop a rash, do not put anything on it unless it is approved by your doctor.
  • Use sunscreen with SPF 15 or higher when you are outdoors, even for a short time.
  • Cover up when you are out in the sun. Wear wide-brimmed hats, long- sleeved shirts, and pants. Keep your neck, chest, and back covered.

When Should I Call the Doctor?

Call your doctor as soon as immediately if you experience:

  • any sign of infection: fever of 100.5F (38C) or higher, chills, cough, sore throat, pain or burning upon urination; redness or tenderness along a vein, at an IV site, or at any other wound or skin irritation
  • any sign of an allergic reaction: itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing, dizziness, or palpitations
  • unusual bruising or bleeding: bleeding lasts more than 10-15 minutes or that causes dizziness; black or bloody stools; vomit that is bloody or that looks like coffee grounds; blood in your urine or phlegm /mucus, unusually heavy menstrual bleeding, spontaneous bleeding from your gums or nose, or superficial bleeding into the skin that appears as a rash of pinpoint-sized reddish-purple spots (petechiae)
  • uncontrolled nausea that prevents you from eating or drinking

Call your doctor as soon as possible if you have:

  • painful mouth or throat that makes it difficult to eat or drink
  • nausea unrelieved by prescribed medication
  • headache unrelieved by prescribed medication
  • yellowing of the skin or eyes
  • persistent loss of appetite or weight loss

What Else Should I Know About Acyclovir?

  • Acyclovir capsules, tablets, and oral suspension may be taken with meals or on an empty stomach.
  • Acyclovir is best taken with a full glass (8ounces) of water.
  • If you are using acyclovir oral suspension, use a specially marked measuring spoon or other device to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.
  • Do not miss any doses but do not use this medicine more often or for a longer time than your doctor ordered.
  • The number of capsules or tablets or teaspoonfuls of suspension that you take depends on the strength of the medicine and on the medical problem you have.
  • If you do miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
  • Store this medicine out of the reach of children and away from heat and direct light.
  • Do not store the capsule or tablet form of this medicine in the bathroom or in other damp places.
  • Do not keep outdated medicine or medicine no longer needed.
  • The areas affected by herpes, chicken pox, or shingles should be kept as clean and dry as possible. Also, wear loose-fitting clothing to avoid irritating the sores (blisters).
  • If you would like more information about acyclovir, talk to your doctor.