Description
Acyclovir is used to treat shingles (herpes zoster), genital herpes, and chickenpox. Although acyclovir will not cure shingles or genital herpes, it does help relieve the pain and discomfort and helps the sores heal faster.
This medicine is available only with your doctor's prescription.
This product is available in the following dosage forms:
- Tablet
- Suspension
- Capsule
- Solution
Before Using
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 this medicine, the following should be considered:
Allergies
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Pediatric
Appropriate studies have not been performed on the relationship of age to the effects of acyclovir in children younger than 2 years of age. Safety and efficacy have not been established.
Geriatric
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of acyclovir in the elderly. Elderly patients are also more likely to have unwanted effects (eg, coma, confusion, dizziness, hallucinations, nausea, sleepiness, vomiting) and age-related kidney disease, which may require caution in patients receiving this medicine.
Breastfeeding
Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.
Drug Interactions
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Fezolinetant
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Bupropion
- Clomipramine
- Dichlorphenamide
- Emtricitabine
- Fexinidazole
- Foscarnet
- Hydroxychloroquine
- Leflunomide
- Mycophenolate Mofetil
- Nitisinone
- Pimozide
- Tenofovir Alafenamide
- Teriflunomide
- Tizanidine
- Vadadustat
- Warfarin
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Fosphenytoin
- Phenytoin
- Valproic Acid
Other Interactions
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other Medical Problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Dehydration or
- Immune system problems or
- Nervous system problems or
- Skin reactions to acyclovir or valacyclovir, severe, history of—Use with caution. May make these conditions worse.
- Kidney disease (eg, patients receiving dialysis)—You may need a dose adjustment. Talk with your doctor if you have concerns about this.
Proper Use
Take this medicine exactly as directed by your doctor. Do not use more of it, do not use it more often, and do not use it for a longer time than your doctor ordered.
Keep using this medicine for the full time of treatment, even if you begin to feel better. Do not stop using it without checking first with your doctor. When your supply of the medicine is running low, contact your doctor or pharmacist ahead of time. Do not allow yourself to run out of the medicine.
If you are taking acyclovir for the treatment of chickenpox, shingles, or genital herpes, it is best to start taking acyclovir as soon as possible after the first sign of the rash or blisters, usually within one day.
You may take this medicine with or without food.
If you are using the oral suspension, shake well before using. 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.
Drink extra fluids so you will pass more urine while you are using this medicine. This will keep your kidneys working well and help prevent kidney problems.
Dosing
The dose of this medicine 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 this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage forms (capsules, oral suspension, or tablets):
- For treatment of genital herpes:
- Adults and children 12 years of age and older—200 milligrams (mg) every 4 hours, 5 times a day for 10 days.
- Children younger than 2 years of age—Use and dose must be determined by the doctor.
- For prevention of recurrent outbreaks of genital herpes infections:
- Adults and children 12 years of age and older—200 to 400 milligrams (mg) 2 to 5 times a day for 12 months, depending on how often your outbreaks of infection occur.
- Children younger than 2 years of age—Use and dose must be determined by the doctor.
- For treatment of chickenpox:
- Adults and children weighing 40 kilograms (kg) or more—800 milligrams (mg) 4 times a day for 5 days.
- Children 2 years of age and older and weighing less than 40 kg—Dose is based on body weight and must be determined by the doctor. The usual dose is 20 mg per kg of body weight 4 times a day for 5 days.
- Children younger than 2 years of age—Use and dose must be determined by the doctor.
- For treatment of shingles:
- Adults and children 12 years of age and older—800 milligrams (mg) every 4 hours, 5 times a day for 7 to 10 days.
- Children younger than 2 years of age—Use and dose must be determined by the doctor.
- For treatment of genital herpes:
- For injection dosage form:
- For treatment of herpes of the brain, genitals, or mucous membranes, or for the treatment of shingles:
- Adults and children 12 years of age and older—Dose is based on body weight and must be determined by the doctor. The usual dose is 5 to 10 mg of acyclovir per kg (2.3 to 4.5 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 up to 12 years of age—Dose is based on body weight and must be determined by the doctor. The usual dose is 10 mg to 20 mg of acyclovir per kg (4.5 mg to 9.1 mg per pound) of body weight, injected slowly into a vein over at least a one-hour period and repeated every eight hours for seven to ten days.
- For treatment of widespread herpes virus infection in newborns:
- Infants from birth to 3 months of age—Dose is based on body weight and must be determined by the doctor. The usual dose is 10 mg of acyclovir per kg (4.5 mg per pound) of body weight, injected slowly into a vein over at least a one-hour period and repeated every eight hours for ten days.
- For treatment of herpes of the brain, genitals, or mucous membranes, or for the treatment of shingles:
Missed Dose
If you 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
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions
It is very important that your doctor check your or your child's progress at regular visits to make sure this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.
This medicine may cause thrombotic thrombocytopenic purpura/hemolytic uremic syndrome. Tell your doctor right away if you have black, tarry stools, blood in the urine, change in mental status, decreased or increased urination, difficulty speaking, fever, pale skin, pinpoint red spots on the skin, seizures, stomach pain, swelling of the face, fingers, feet, or lower legs, unusual bleeding or bruising, unusual tiredness or weakness, or yellow eyes or skin.
Check with your doctor right away if you have bloody urine, decreased amount of urine, increased thirst, lower back or side pain, loss of appetite, nausea or vomiting, swelling of the face, fingers, or lower legs, trouble breathing, or weight gain. These may be symptoms of serious kidney problems.
This medicine may cause serious skin reactions, including acute generalized exanthematous pustulosis (AGEP), drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis, and erythema multiforme. Check with your doctor right away if you have black, tarry stools, blistering, peeling, or loosening of the skin, chest pain, chills, cough, diarrhea, fever, itching, joint or muscle pain, painful or difficult urination, red irritated eyes, red skin lesions, often with a purple center, sore throat, sores, ulcers, or white spots on the lips or in the mouth, swollen glands, trouble breathing, unusual bleeding or bruising, or unusual tiredness or weakness.
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 may help prevent the spread of herpes.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Side Effects
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
- Pain, swelling, or redness at place of injection
Less common
- Decreased frequency of urination or amount of urine
- increased thirst
- loss of appetite
- nausea or vomiting
- stomach pain
- unusual tiredness or weakness
Rare
- Black, tarry stools
- blood in urine or stools
- chills, fever, or sore throat
- confusion
- hives
- pinpoint red spots on skin
- seeing, hearing, or feeling things that are not there
- seizures
- trembling
- unusual bleeding or bruising
Incidence not known
- Bleeding or oozing from puncture sites or mucous membranes (bowel, mouth, nose, or urinary bladder), continuing
- blistering, peeling, or loosening of the skin
- bloating or swelling of the face, arms, hands, lower legs, or feet
- bluish coloring, especially of the hands and feet
- blurred vision
- bruising at the place of injection
- change or loss of consciousness
- changes in facial skin color
- changes in vision
- clumsiness
- coughing
- difficulty in breathing or swallowing
- dizziness or feeling faint, severe
- fast heartbeat
- irritability
- itching or skin rash
- large hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
- mood or mental changes
- muscle cramps, pain, or weakness
- pale skin
- rapid weight gain
- red or irritated eyes
- red skin lesions, often with a purple center
- sense of agitation or uneasiness
- shakiness and unsteady walk
- sores, ulcers, or white spots in the mouth or on the lips
- swelling of eyelids, face, feet, hands, lower legs or lips
- swollen, painful, or tender lymph nodes (glands) in neck, armpit, or groin
- tingling of the hands or feet
- unsteadiness or other problems with muscle control or coordination
- yellow eyes or skin
Some 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. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
- General feeling of discomfort or illness
Less common
- Diarrhea
- headache
Incidence not known
- Burning, prickling, or tingling sensations
- drowsiness
- loss of hair
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
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