Acyclovir (By Mouth)

Acyclovir (ay-SYE-kloe-veer)

Treats herpes virus infections, including shingles (herpes zoster) and genital herpes (herpes simplex). Also treats chickenpox. This medicine will not cure herpes, but may prevent a breakout of herpes sores or blisters.

Brand Name(s):

Zovirax
There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have had an allergic reaction to acyclovir or to similar medicines such as famciclovir (Famvir®), ganciclovir (Cytovene®, Vitrasert®), valacyclovir (Valtrex®), or valganciclovir (Valcyte™).

How to Use This Medicine:

Capsule, Tablet, Liquid

• Your doctor will tell you how much of this medicine to use and how often. Do not use more medicine or take it more often than your doctor tells you to.
• Take this medicine at the first sign of a herpes breakout, or as soon as possible after you are diagnosed with herpes zoster. The medicine may not work if you wait longer than 3 days to start using it.
• You may take this medicine with or without food. Drink plenty of liquids while you are taking acyclovir.
• Shake the oral liquid thoroughly before each use. Measure the medicine with a marked measuring spoon or medicine cup.

If a dose is missed:

• If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

• Store the medicine at room temperature, away from heat, moisture, and direct light.
• Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
• Keep all medicine away from children and never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Make sure your doctor knows if you are also using phenytoin (Dilantin®), fosphenytoin (Cerebyx®), probenecid (Benemid®), valproic acid (Depekene®), or medicines that weaken the immune system (such as steroids, chemotherapy, or radiation).

Warnings While Using This Medicine:

• Make sure your doctor knows if you are pregnant or breastfeeding, or if you have kidney disease or a weakened immune system. Some things that cause a weak immune system are cancer chemotherapy, HIV/AIDS, recent infection, or recent bone marrow or kidney transplant.
• Acyclovir will not stop the spread of herpes during sex. Avoid having sex while you have herpes sores.
• Even if you have no signs of a herpes infection, it is still possible to spread the virus to others during sex. Talk with your doctor about ways to keep from spreading the virus.
• Tell your doctor if your symptoms do not improve after taking this medicine for several days.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in face or hands, swelling or tingling in the mouth or throat, tightness in chest, trouble breathing
• Blistering, peeling, red skin rash
• Confusion, agitation, behavior changes
• Decrease in how much or how often you urinate
• Fainting or extreme weakness, problems with walking or coordination
• Pinpoint red spots on your skin
• Unexplained fever
• Unusual bleeding or bruising, blood in urine or stools
• Yellow eyes or skin

If you notice these less serious side effects, talk with your doctor:

• Muscle pain
• Nausea, vomiting, diarrhea, or upset stomach
• Nervousness or tired feeling
• Problems with vision

If you notice other side effects that you think are caused by this medicine, tell your doctor.