Antivirals: acyclovir (Zovirax®)

acyclovir (Zovirax®)

Acyclovir belongs to the family of medicines called antivirals, which are used to treat infections caused by viruses. Usually these medicines work for only one kind or group of virus infections.

Acyclovir is used to treat the symptoms of herpes virus infections of the genitals (sex organs), the skin, the brain, and mucous membranes (lips and mouth). Acyclovir is also used to treat chickenpox and shingles. Although acyclovir will not cure herpes, it does help relieve the pain and discomfort and helps the sores (if any) heal faster.

Acyclovir may also be used for other virus infections as determined by your doctor. However, it does not work in treating certain viruses, such as the common cold.

Acyclovir is available only with your doctor's prescription, in the following dosage forms:
Oral

Capsules (U.S. and Canada)
Oral suspension (U.S. and Canada)
Tablets (U.S. and Canada)

Parenteral

Injection (U.S. and Canada)

Before Using Acyclovir

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For acyclovir, the following should be considered:

Allergies:
Tell your doctor if you have ever had any unusual or allergic reaction to acyclovir or ganciclovir. Also tell your health care professional if you are allergic to any other substances, such as foods, sulfites or other preservatives, or dyes.

Pregnancy:
Acyclovir has been used in pregnant women and has not been reported to cause birth defects or other problems. However, studies have not been done in humans. Studies in rabbits have shown that acyclovir given by injection may keep the fetus from becoming attached to the lining of the uterus (womb). However, acyclovir has not been shown to cause birth defects or other problems in mice given many times the usual human dose, or in rats or rabbits given several times the usual human dose.

Breast-feeding:
Acyclovir passes into the breast milk. However, it has not been reported to cause problems in nursing babies.

Children:
A limited number of studies have been done using oral acyclovir in children, and it has not caused different effects or problems in children than it does in adults.

Older adults:
Acyclovir has been used in the elderly and has not been shown to cause different side effects or problems in older people than it does in younger adults.

Other medicines:
Although certain medicines should not be used together at all, in many cases two different medicines may be used together even if an interaction might occur. In these cases, changes in dose or other precautions may be necessary. If you are receiving acyclovir by injection it is especially important that your health care professional know if you are taking any of the following:

Carmustine (e.g., BiCNU) or
Cisplatin (e.g., Platinol) or
Combination pain medicine containing acetaminophen and aspirin (e.g., Excedrin) or other salicylates or
Cyclosporine (e.g., Sandimmune) or
Deferoxamine (e.g., Desferal) (with long-term use) or
Gold salts (medicine for arthritis) or
Inflammation or pain medicine, except narcotics, or
Lithium (e.g., Lithane) or
Methotrexate (Mexate) or
Other medicine for infection or
Penicillamine (e.g., Cuprimine) or
Plicamycin (e.g., Mithracin) or
Streptozocin (e.g., Zanosar) or
Tiopronin (Thiola) -- Concurrent use of these medicines with acyclovir by injection may increase the chance for side effects, especially when kidney disease is present

Other medical problems:
The presence of other medical problems may affect the use of acyclovir. Make sure you tell your doctor if you have any other medical problems, especially:

Kidney disease -- Kidney disease may increase blood levels of acyclovir, increasing the chance of side effects
Nerve disease -- Acyclovir by injection may increase the chance for nervous system side effects

Proper Use of Acyclovir

Patient information about the treatment of herpes is available with this medicine. Read it carefully before using this medicine.

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

Acyclovir capsules, tablets, and oral suspension may be taken with meals.

If you are taking acyclovir for the treatment of chickenpox, it is best to start taking acyclovir as soon as possible after the first sign of the chickenpox rash, usually within one day.

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.

Acyclovir is best taken with a full glass (8 ounces) of water.

To help clear up your herpes infection, acyclovir must be taken for its full time of treatment, even if your symptoms begin to clear up after a few days. Don't miss any doses, and don't use this medicine more often or for a longer period of time than your doctor ordered.

Dosing:
The dose of acyclovir will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of acyclovir. Your dose may be different if you have kidney disease.
If your dose is different, do not change it unless your doctor tells you to:

The number of capsules or tablets or teaspoonfuls of suspension that you take depends on the strength of the medicine. Also, the number of doses you take daily, the time allowed between doses, and the length of time you take the medication depend on the medical problem for which you are taking acyclovir.

For ORAL dosage forms (capsules, oral suspension, or tablets):
For treatment of herpes of the genitals or mucous membranes, or for shingles:
Adults and children 12 years of age and older -- 200 to 800 milligrams (mg) two to five times a day for up to ten days.
Children younger than 12 years of age -- Use and dose must be determined by the doctor.

For treatment of chickenpox:

Adults and children 2 years of age and older -- Dose is based on body weight. The usual dose is 20 mg per kilogram (kg) of body weight, up to 800 mg, four times a day for five days.
Children younger than 2 years of age -- Use and dose must be determined by the doctor.
For INJECTION dosage form:
For treatment of herpes of the genitals or mucous membranes, or for shingles:
Adults and children 12 years of age and older -- Dose is based on body weight. The usual dose is 5 to 10 mg of acyclovir per kg (2.3 to 4.6 mg per pound) of body weight, injected slowly into a vein over at least a one-hour period, and repeated every eight hours for five to ten days.
Children younger than 12 years of age -- Dose is based on body weight or body size. The medicine is injected slowly into a vein over at least a one-hour period and repeated every eight hours for five to ten days.

Missed dose:
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.

Storage:
To store this medicine:

Keep out of the reach of children.
Store away from heat and direct light.
Do not store the capsule or tablet form of this medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Precautions While Using Acyclovir

Women with genital herpes may be more likely to get cancer of the cervix. Therefore, it is very important that a Pap test be taken at least once a year to check for cancer. Cervical cancer can be cured if found and treated early.

If your symptoms do not improve within a few days, or if they become worse, check with your doctor.

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).

Acyclovir will not prevent you from spreading herpes to other people.

Herpes infection of the genitals can be caught from or spread to your partner during any sexual activity. Even though you may get herpes if your partner has no symptoms, the infection is more likely to be spread if sores are present. This is true until the sores are completely healed and the scabs have fallen off. So avoid any sexual activity if either you or your partner has any symptoms of herpes. The use of a latex condom may help prevent the spread of herpes. However, spermicidal (sperm-killing) jelly or a diaphragm will probably not help.

Side Effects of Acyclovir

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Call your doctor immediately if any of the following side effects occur:

For acyclovir injection only More common

Pain, swelling, or redness at place of injection

Less common (more common with rapid injection)

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

Rare

Confusion; convulsions (seizures); hallucinations (seeing, hearing, or feeling things that are not there); trembling

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:
For oral acyclovir only

Diarrhea; headache; lightheadedness; nausea or vomiting

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

DISCLAIMER:
The information about drugs featured by HIVpositive.us is general in nature and is intended for educational use. It does not cover all possible uses, actions, precautions, side effects, or interactions of any medicines, nor is the information intended as medical advice for individual problems or for making an evaluation as to the risks and benefits of taking a particular drug.
See "Full Disclaimer."

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