Aciclovir is the generic name for Zovirax, a prescription medication used to treat certain virus infections.
The Food and Drug Administration (FDA) approved aciclovir to treat viral infections from the varicella virus that causes chicken pox and shingles, as well as infections from the virus that causes genital herpes. Sometimes doctors prescribe aciclovir to treat herpes infections in people with HIV. The drug works by preventing viruses from dividing and multiplying. The FDA approved aciclovir in the 1980s.
Aciclovir is available as a generic, made by several companies, or under the brand name Zovirax, made by GlaxoSmithKline and available in tablet, capsule, and liquid form. Aciclovir is one of the oldest drugs used to treat herpes simplex viruses and remains the first line of treatment for these infections.
However, research shows that aciclovir is not as effective as it used to be.
A 2013 study, published in the journal Current Opinion in Infectious Diseases, found that acyclovir-resistant herpes strains could develop over time.
Resistance happens in people with a healthy immune system as well as in those with a weakened immune system.
It’s important to know that aciclovir does not cure viral infections. However, it can make infections shorter and less serious for some people.
If you’re taking aciclovir for genital herpes, it can reduce the severity or prevent recurrences of a herpes outbreak.
If you’re taking aciclovir to treat chicken pox or shingles, the drug can reduce the severity of your infection.
It’s important to know that treatment with aciclovir works best when you start taking it as soon as possible after a rash appears. This means within three days of a shingles rash and within 24 hours of a chicken pox rash.
It’s usually not necessary to treat young, healthy children with chicken pox, but older children or adults who get chicken pox may need treatment.
Drink plenty of fluids when taking this medication. Children younger than 2 should not take aciclovir. Use aciclovir with caution if you have kidney disease or any condition that weakness your immune system. If you have these conditions, you could be at risk for serious reactions to aciclovir.
Ask your doctor for advice on practicing safe sex if you have a genital herpes infection. Genital herpes spreads through sexual activity, and taking aciclovir alone may not be enough to prevent it.
Aciclovir and Pregnancy
If you’re a woman, let your doctor know if you are or may be pregnant or if you’re breastfeeding. Researchers have not studied aciclovir use by pregnant women, so there’s not enough evidence to say that it is safe to take during pregnancy.
Aciclovir also may pass into breast milk.
Aciclovir Side Effects
The most common side effects of aciclovir treatment for genital herpes include nausea, vomiting, and diarrhea.
Shingles requires treatment with higher doses of aciclovir, and the most common side effects at higher doses are tiredness and malaise.
Tell your doctor if you have any side effects. Side effects that may be seen in all people using aciclovir include:
- Muscle or joint aches
- Visual changes
- Fluid retention
- Hair loss
- Changes in behavior
Serious side effects also can occur. If you have any of these side effects, call your doctor right away:
- Severe rash, hives, or a rash that causes blisters and peeling
- Yellowing of skin or eyes
- Unusual bleeding or bruising
- Loss of consciousness
- Swelling of face, lips, or tongue
- Difficulty breathing
- Decreased urine output or blood in the urine
- Extreme sleepiness or confusion
- Tingling, numbness, or shakiness
Age matters, too. People older than 65 may have more side effects from aciclovir because their kidneys do not get rid of the drug as quickly as younger people’s do.
Some drugs may affect the way aciclovir works, and aciclovir may affect other drugs you are taking.
It’s very important to let your doctor know about all drugs you are taking, including any over-the-counter herbs or supplements.
Drugs that may interact with aciclovir include:
- Several medications used to treat bacterial or fungal infections, including amphotericin B (Fungizone)and several antibiotics such as amikacin (Amikin), gentamicin (Garamycin), kanamycin (Kantrex) and tobramycin (Tobi, Nebcin)
- Over-the-counter pain relievers (Advil, Motrin, Aleve)
- Medications used to treat HIV/AIDS, such as zidovudine(Retrovir, AZT)
Other Aciclovir Interactions
You do not need to change your diet or your activities while on aciclovir.
However, drink plenty of fluids when taking this medication.
Your dose of aciclovir will depend on why you’re taking it.
Aciclovir comes in tablets, capsules, and liquid form. You can take it with or without food.
Lower doses may be best for elderly people and for anyone with kidney disease.
Common dosages are:
- For treatment of shingles: 800 milligrams (mg) five times daily for 7 to 10 days
- For genital herpes treatment: 200 mg five times daily for 10 days
- For preventing a recurrence of genital herpes: 400 mg every 12 hours for 12 months
- For treating chicken pox in adults and children who weigh more than 40 pounds: 800 mg four times daily for 5 days
An overdose of aciclovir can cause kidney damage.
Symptoms of an overdose may include:
- Extreme sleepiness
- Loss of consciousness
- Kidney failure (no urine production)
Missed Dose of Aciclovir
You should take aciclovir exactly as directed by your doctor. Also, do not stop taking aciclovir on your own.
Skipping doses or stopping too soon may not completely treat your infection, or it could make the infection harder to treat.
If you miss a dose of aciclovir, take the missed dose as soon as you remember.
If it’s almost time for your next dose, skip the missed dose.
Do not double your dose to make up for a missed dose.
How to store aciclovir
- Keep all medicines out of the reach and sight of children.
- Store in a cool, dry place, away from direct heat and light.
Can aciclovir cause problems?
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the more common ones associated with aciclovir. The best place to find a full list of the side-effects which can be associated with your medicine, is from the manufacturer’s printed information leaflet supplied with the medicine. Alternatively, you can find an example of a manufacturer’s information leaflet in the reference section below. Speak with your doctor or pharmacist if any of the following continue or become troublesome.
|Common aciclovir side-effects (these affect less than 1 in 10 people)||What can I do if I experience this?|
|Feeling sick or being sick (vomiting), stomach ache||Stick to simple foods – avoid fatty or spicy meals|
|Itchy rash, feeling hot||If either are troublesome, speak with your doctor|
|Headache||Drink plenty of water and ask your pharmacist to recommend a suitable painkiller. If the headache continues, speak with your doctor|
|Diarrhoea||Drink plenty of water to replace any lost fluids|
|Feeling dizzy or tired||Do not drive and do not use tools or machines while affected|
If you experience any other symptoms which you think may be due to the medicine, speak with your doctor or pharmacist for further advice.
Q & A
Q: Can you please tell me if there are any long-term side effects to taking 800mg of aciclovir each day? Can this cause liver, kidney, or heart damage?
A: The most common adverse reactions associated with aciclovir ken orally include malaise (generalized discomfort), headaches, nausea, vomiting and diarrhea. aciclovir used topically has the following as the most common adverse reactions: mild pain, burning or stinging and pruritus (itching). There have been rare (less than 1 percent of studied patients) that have had suspected effects on various organ systems such as liver, kidneys, heart, etc. As always, talk with your health care provider regarding questions you have about side effects of your prescription medications. Jen Marsico, RPh
Q: Can Aciclovir cause uncontrollable muscle twitching?
Aciclovir (Zovirax)aciclovir is a medication used to treat viral infections. The most common side effects associated with the oral form of Aciclovir are diarrhea, nausea, vomiting, headache, and feeling tired (malaise). Aciclovir cream and ointment can cause skin irritation. A search of the prescribing information for Aciclovir did not specifically list uncontrollable muscle twitching as a side effect. Tell your health-care provider about any negative side effects from prescription drugs. You can also report them to the U.S. Food and Drug Administration by visiting www.fda.gov/medwatch or by calling 1-800-FDA-1088. For more specific information, consult with your doctor or pharmacist for guidance based on your health status and current medications, particularly before taking any action. Lori Mendoza, PharmD
Q: What is aciclovir?
A: Aciclovir (Zovirax) is an antiviral medication indicated for the acute treatment of herpes zoster (shingles), the treatment of initial episodes and the management of recurrent episodes of genital herpes and the treatment of chickenpox. Aciclovir is only approved, by the U.S. Food and Drug Administration (FDA), for the treatment of chickenpox in the pediatric population 2 year of age and older. The safety and effectiveness of oral aciclovir in the pediatric population, younger than 2 years of age, has not been established. The dosage and administration of oral aciclovir depends upon the indication for use and age of the patient. Aciclovir can be administered with or without food. Aciclovir is the generic equivalent of Zovirax and is currently available, for oral administration, in capsule and tablet form and as a suspension for patients who have difficulty swallowing pills. Treatment with aciclovir should be initiated as soon as possible after the first appearance of symptoms, such as tingling, burning or blisters. Patients being treated with aciclovir are advised to stay adequately hydrated and take each dose with a full glass of water to protect the kidneys. The most frequently reported adverse reactions differed among clinical trials of aciclovir depending on the indication for use. During clinical trials of treatment with aciclovir, the most frequently reported adverse reactions included nausea, vomiting, diarrhea, malaise and headache. For the treatment of shingles, there is no information regarding initiation of treatment more than 72 hours following the onset of rash. Patients should initiate treatment as soon as possible after diagnosis. For the treatment of chickenpox, information gathered during clinical studies reflects initiation of treatment within 24 hours following rash. There is no information available regarding the effectiveness of treatment initiated after 24 hours. Patients should be advised that aciclovir is not a cure for genital herpes and there is no available research regarding whether aciclovir will prevent the transmission of the virus to other individuals.
Q: What are the side effects of aciclovir?
A: The most frequently reported side effects of aciclovir (Zovirax), for oral administration, differed in clinical trials depending on the indication for use. During clinical trials of treatment of genital herpes, with short-term administration of aciclovir, the most frequently reported adverse reactions included nausea and/or vomiting. During clinical trials of treatment with long-term administration with aciclovir for genital herpes, there were two methods of administration evaluated. In trials evaluating continuous administration to prevent recurrences, the most frequently reported adverse reactions included nausea and diarrhea and in those evaluating intermittent treatment of recurrences over one year diarrhea, nausea and headache were reported. The most frequently reported adverse reaction during clinical trials of shingles was malaise. Lastly, during clinical trials of treatment of chickenpox with aciclovir, the most frequently reported adverse reaction was diarrhea. More serious side effects of aciclovir are possible with treatment. Kidney failure, in some cases causing death, has been reported with aciclovir treatment. Patients are advised to maintain adequate hydration and drink plenty of water while taking aciclovir to keep the kidneys working properly. There is also a warning regarding thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS), which has occurred in immunocompromised patients administered aciclovir. Patients should be advised to contact their health care provider immediately if they experience symptoms which may indicate the occurrence of more serious side effects of aciclovir. Symptoms may include pain the lower back, urinating less than usual or not urinating at all, easy bruising or bleeding, and unusual weakness. Patients are instructed to consult with their health care provider if they experience any other unusual, severe or troublesome side effects while being treated with aciclovir.
Q: Is there an aciclovir ointment?
A: There is an aciclovir (Zovirax) ointment formulation, available in 5% strength. Currently, aciclovir ointment is only available as the brand-name Zovirax Ointment 5%. Aciclovir ointment is indicated for the management of initial genital herpes and in limited non-life threatening mucocutaneous herpes simplex virus infections in immunocompromised patients. Aciclovir ointment is not indicated for the prevention of viral transmission to other individuals. Aciclovir ointment is also not indicated for the prevention of recurrent herpes infections. Aciclovir ointment is a prescription ointment that is applied directly to genital herpes lesions and may lessen the duration of the symptoms associated with an initial outbreak. For the management of genital herpes, patients should be instructed regarding appropriate dosage and administration of aciclovir ointment. Patients should be advised to apply a sufficient quantity of aciclovir ointment to adequately cover all lesions and apply every 3 hours, 6 times daily, for 7 days of treatment. The dose size of aciclovir ointment for each application may vary depending on the size of the lesion area. However, the dose size should be approximately Â½ inch ribbon of aciclovir ointment per 4 square inches of surface area, according to the prescribing information. Patients should be advised to wear a rubber glove or finger cot when applying aciclovir ointment to the affected area to avoid spreading the virus. Aciclovir ointment should be applied as early as possible after the development of signs and symptoms. During controlled clinical trials, mild pain, including temporary burning and stinging, was reported in approximately 30% of patients with no significant difference between patients receiving Zovirax ointment and patients receiving placebo. Local pruritus was also reported in 4% of patients. Aciclovir ointment 5% should be used exactly as prescribed by a health care provider. Patients should be advised not to exceed the recommended dosage, frequency of applications and length of treatment.
Q: How long is aciclovir treatment?
A: How long aciclovir (Zovirax) treatment is intended for depends upon the indication for use. Aciclovir is a prescription antiviral agent approved, by the U.S. Food and Drug Administration (FDA), for the acute treatment of herpes zoster (shingles), the treatment of initial episodes and the management of recurrent episodes of genital herpes and the treatment of chickenpox. Aciclovir treatment is approved for all indications for adults and for the treatment of chickenpox in children 2 year of age and older. For the acute treatment of shingles, the length of aciclovir treatment is 7 to 10 days. The usual recommended adult dosage is 800 mg administered every 4 hours, 5 times daily. For the treatment of initial episodes of genital herpes, the length of aciclovir treatment is 10 days. The usual recommended adult dosage is 200 mg administered every 4 hours, 5 times daily. For the management of recurrent episodes of genital herpes, there were two methods of administration of aciclovir treatment evaluated in clinical trials. For intermittent therapy, the length of aciclovir treatment is 5 days. Treatment should be initiated at the earliest sign or symptom of recurrence, known as a prodrome. The usual adult dosage is 200 mg administered every 4 hours, 5 times daily. The other option is chronic suppressive therapy in which aciclovir treatment is used for up to 12 months and followed by re-evaluation by a health care provider to assess the need for continued treatment. The usual adult dosage is 400 mg twice daily. Alternative dosages may range from 200 mg 3 times daily to 200 mg 5 times daily, according to the prescribing information for Zovirax, the brand-name of aciclovir. For the treatment of chickenpox for adults and children, the recommended length of aciclovir treatment is 5 days. When treatment is required, it should be initiated at the earliest sign or symptom of chickenpox. The effectiveness of treatment initiated after 24 hours following the onset of symptoms is unknown. The usual dosage for adults and children weighing over 40 kg is 800 mg administered 4 times daily. The usual dosage for children 2 years of age and older is 20 mg/kg per dose administered 4 times daily.
Q: Does aciclovir cause hair loss?
A: During post marketing experience, observed in clinical practice, aciclovir (Zovirax) was reported to cause hair loss. However, because adverse reactions reported in clinical practice, and not during controlled clinical trials, are reported voluntarily from an unknown population size, the frequency of the adverse reaction is unknown. Other adverse reactions reported during post marketing experience with aciclovir included headache, allergic reaction, fever, pain, swelling in the extremities, agitation, confusion, dizziness, somnolence, tremors, diarrhea, gastrointestinal distress, nausea, anemia, leucopenia, thrombocytopenia, elevated liver enzymes, hepatitis, jaundice, myalgia, prutitus, rash, visual disturbances, kidney failure, kidney pain, elevated blood urea nitrogen (BUN) and creatinine, and hematuria. According to the prescribing information for Zovirax, the brand-name of aciclovir, the most frequently reported adverse reactions reported during clinical trials included nausea, vomiting, diarrhea, malaise and headache and varied depending on the indication for treatment. Patients are instructed to contact their health care provider, immediately, if they experience symptoms which may indicate more serious adverse reactions of aciclovir have developed. Symptoms may include pain the lower back, urinating less than usual or not urinating at all, easy bruising or bleeding, and unusual weakness. It is important for patients to report any unusual or bothersome reactions they experience while being treated with aciclovir. Aciclovir should be taken exactly as prescribed.
Q: Are there any aciclovir interactions with other medications?
A: There are not many aciclovir (Zovirax) interactions with other medications. If aciclovir interacts with certain other medications, the effects can be increased, decreased or altered. One aciclovir interaction possible is with the medication probenecid (Benemid). It is especially important for patients taking probenecid to consult with a health care provider prior to treatment with aciclovir. If you are currently taking probenecid, you may not be able to take aciclovir, or you may require dosage adjustments of special tests during treatment. Some of the other possible aciclovir interactions with other medications may include Demerol (meperidine), Dilantin (phenytoin), Cellcept (mycophenolate mofetil), Viread (tenofovir), Zanaflex (tizanidine), Depakene (valproic acid), Retrovir (zidovudine), theophyllines and the varicella virus vaccine. It is essential for patients to consult with their health care provider regarding all prescription and over the counter medications they take prior to initiation of treatment with aciclovir to avoid potentially dangerous drug interactions. This includes all vitamins, minerals, herbal supplements and any drugs prescribed by another doctor.
Q: Does aciclovir cause stomach pain?
A: During clinical trials, patients did not report aciclovir (Zovirax) causing stomach pain. However, most of the frequently reported adverse reactions associated with aciclovir treatment were related to the gastrointestinal system. According to the prescribing information for Zovirax, the brand-name equivalent of aciclovir, the most frequently reported gastrointestinal adverse reactions reported by patients during clinical trials for any indication included nausea, vomiting and diarrhea. In addition, post marketing experience revealed other gastrointestinal related adverse reactions observed in clinical practice. In clinical practice experience with aciclovir, patients reported experiencing diarrhea, gastrointestinal distress and nausea. There was no further description regarding gastrointestinal distress and whether or not patients experienced stomach pain specifically. Other common adverse reactions possible with aciclovir treatment include headache and malaise. It is essential for patients to consult a health care provider if they experience any unusual or bothersome adverse reactions while being treated with aciclovir for further evaluation. Aciclovir is an antiviral medication available by prescription only. Aciclovir is indicated for the acute treatment of shingles, the treatment of initial episodes and the management of recurrent episodes of genital herpes and the treatment of chickenpox. Aciclovir is approved for use in adults for all indications and for the treatment of chickenpox in the pediatric population in children 2 years of age and older. Aciclovir may be taken without regard to food and should be taken exactly as instructed by a health care provider.
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