Zovirax Precautions & Side Effects

Before Using ZOVIRAX
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 valacyclovir. 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 rats and 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 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 - Agitation, confusion, dizziness, and drowsiness may be especially likely to occur in elderly patients who are usually more sensitive than younger adults to the central nervous system effects of acyclovir.

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 taking acyclovir 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 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:

• Dehydration or
• Kidney diseaseDehydration or kidney disease may increase blood levels of acyclovir, increasing the chance of side effects

• Nervous system problemsAcyclovir may make these problems worse

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

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

It is important to remember that acyclovir will not keep you from spreading herpes to others.

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. Therefore, it is best to avoid any sexual activity if either you or your sexual partner has any symptoms of herpes. The use of a latex condom (rubber') may help prevent the spread of herpes. However, spermicidal (sperm-killing) jelly or a diaphragm will probably not help.

Side Effects of ZOVIRAX
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. Check with your doctor immediately if any of the following side effects occur:

More common

For acyclovir injection only
Pain, swelling, or redness at place of injection

Less common

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

Black, tarry stools, blood in urine or stools, chills, fever, or sore throat, confusion, convulsions (seizures), hallucinations (seeing, hearing, or feeling things that are not there), hives, pinpoint red spots on skin, trembling, unusual bleeding or bruising

Frequency not determined

Bleeding or oozing from puncture sites or mucous membranes (bowel, mouth, nose, or urinary bladder), continuing, blistering, peeling, or loosening of skin, bluish coloring, especially of the hands and feet, blurred vision, bruising at the place of injection, changes in facial skin color, changes in vision, clumsiness, coughing, decreased consciousness, difficulty in breathing or swallowing, dizziness or feeling faint, severe , fast heartbeat, irritability , itching or skin rash, large hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, sex organs, mood or mental changes, muscle cramps, pain, or weakness, pale skin, red or irritated eyes, sense of agitation or uneasiness, shakiness and unsteady walk, sores, ulcers, or white spots in mouth or on lips, swelling of eyelids, face, feet, hands, lower legs or lips, swollen, painful, or tender lymph nodes (glands) in neck, armpit, or groin, unsteadiness or other problems with muscle control or coordination, yellow eyes or skin

More common

Especially seen with high doses
General feeling of discomfort or illness

Less common

Especially seen with long-term use or high doses
Diarrhea, headache

Frequency not determined

Burning, prickling, or tingling sensations, drowsiness, loss of hair

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

IMPORTANT NOTE: The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.