Are Acyclovir And Valacyclovir The Same
Acyclovir and valacyclovir are closely related chemically, but they are not the same drug. Valacyclovir is the prodrug of acyclovir. During first-pass metabolism of the oral dosage form, valacyclovir is converted to acyclovir, allowing more active ingredients to be absorbed from oral administration and also allowing more time between doses.
Dosage For Shingles Genital Herpes Or Chickenpox
Adult dosage
- Shingles typical dosage: 800 mg every 4 hours, five times per day for 710 days.
- Genital herpes:
- Typical initial dosage: 200 mg every 4 hours, five times per day, for 10 days.
- Typical dosage for prevention of recurrent herpes: 400 mg twice per day, every day for up to 12 months. Other dosing plans may include doses ranging from 200 mg three times daily to 200 mg five times daily. Your doctor will decide how long you should take this drug to avoid a flare-up of the infection.
- Typical dosage for reinfection : 200 mg every 4 hours, five times per day, for 5 days. You should take this drug as soon as the first signs of a flare-up appear.
Child dosage
- Chickenpox typical dosage:
- Children who weigh 40 kg or less: 20 mg/kg of body weight, given four times per day for 5 days
- Children who weigh more than 40 kg: 800 mg four times per day for 5 days
Start this drug as soon as the first symptom of chickenpox appears. It isnt known if this drug is effective if your child starts it more than 24 hours after the first sign of chickenpox.
Child dosage
It hasnt been confirmed that acyclovir is safe and effective for children younger than 2 years.
Senior dosage
How Should I Take Acyclovir
Take acyclovir exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.
Start taking acyclovir as soon as possible after the first appearance of symptoms . Start taking Sitavig within 1 hour after you first notice sold core symptoms, before the cold sore appears.
Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you do not understand these instructions.
Do not crush, chew, suck on, or swallow a buccal tablet. Place the flat side of the tablet against your upper gum, on the same side of the mouth as your cold sore. Allow the tablet to dissolve in your mouth throughout the day. You may eat and drink normally while the buccal tablet is in place.
Do not give an acyclovir buccal tablet to a young child or choking could occur.
Shake the oral suspension before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device .
Acyclovir doses are based on weight . Your dose needs may change if you gain or lose weight.
Drink plenty of water while you are taking this medicine to keep your kidneys working properly.
Use this medicine for the full prescribed length of time, even if your symptoms quickly improve. Skipping doses may increase the risk of your virus becoming resistant to medication.
Store at room temperature away from moisture and heat.
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Are There Any Other Precautions Or Warnings For This Medication
Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Drowsiness/reduced alertness: Acyclovir may affect the mental or physical abilities needed to drive or operate machinery. Avoid driving, operating machinery, or performing other hazardous tasks until you have determined how this medication affects you.
Genital herpes: To reduce the risk of spreading the virus, wash your hands immediately after touching your skin sores. You should avoid intimate contact when live lesions are visible on your skin. The herpes virus can still be spread even when you do not have blisters or sores.
Kidney function: Kidney disease or reduced kidney function may cause this medication to build up in the body, causing side effects. If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
People with reduced kidney function generally require a lower dose of this medication.
Children: The safety and effectiveness of using this medication have not been established for children less than 2 years of age.
How Should I Use This Medication
Genital herpes: The usual recommended adult dose for treating genital herpes is 200 mg every 4 hours, 5 times daily for 10 days. The usual recommended adult dose for preventing genital herpes infection from coming back varies but usually starts at 200 mg 3 times daily. You should start acyclovir as early as possible following the onset of signs and symptoms.
Shingles: The recommended dose for treating shingles is 800 mg every 4 hours, 5 times daily for 7 to 10 days. Treatment should be started within 48 hours of onset of the rash or lesions for maximum benefit, however it may be started as late as 72 hours after lesions begin to form.
Chickenpox: The recommended dose for chickenpox is based on body weight. The usual dose is 20 mg per kilogram of body weight 4 times daily for 5 days. Therapy should be started within 24 hours of onset of the rash.
Tablets should be swallowed whole, with water. If you are using the suspension, the bottle should be shaken well before use. Use an oral syringe to measure each dose of the suspension, as it gives a more accurate measurement than household teaspoons.
Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.
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How To Take Acyclovir
Use Acyclovir exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.
Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.
Start taking acyclovir as soon as possible after the first appearance of symptoms . Start taking Sitavig within 1 hour after you first notice sold core symptoms, before the cold sore appears.
Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you do not understand these instructions.
Do not crush, chew, suck on, or swallow a buccal tablet. Place the flat side of the tablet against your upper gum, on the same side of the mouth as your cold sore. Allow the tablet to dissolve in your mouth throughout the day. You may eat and drink normally while the buccal tablet is in place.
Do not give an acyclovir buccal tablet to a young child or choking could occur.
Shake the oral suspension before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device .
Acyclovir doses are based on weight . Your dose needs may change if you gain or lose weight.
Drink plenty of water while you are taking acyclovir to keep your kidneys working properly.
Lesions caused by herpes viruses should be kept as clean and dry as possible. Wearing loose clothing may help to prevent irritation of the lesions.
Are There Any Alternatives
There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.
Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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Usual Adult Dose For Herpes Simplex
Treatment of First Episode of Genital Herpes:200 mg orally every 4 hours 5 times a day for 10 days 400 mg orally 3 times a day for 5 to 10 days Severe Disease or Complications Requiring Hospitalization:5 mg/kg IV every 8 hours for 5 days 5 to 10 mg/kg IV every 8 hours for 2 to 7 days or until clinical improvement is observed, followed by oral antiviral therapy to complete at least 10 days of total therapy Episodic Therapy: Effective treatment requires therapy initiation within 1 day of lesion onset or during the prodrome preceding an episode/recurrence200 mg orally every 4 hours 5 times a day for 5 days 400 mg orally 3 times a day for 5 days OR 800 mg orally 2 times a day for 5 days OR 800 mg orally 3 times a day for 2 days
What Should I Know About Storage And Disposal Of This Medication
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture .
It is important to keep all medication out of sight and reach of children as many containers are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location â one that is up and away and out of their sight and reach.
Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website for more information if you do not have access to a take-back program.
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What Should I Avoid While Taking Valacyclovir
It is important to avoid other drugs which have the potential for nephrotoxicity when taking valacyclovir. This includes other antivirals such as adefovir, cidofovir, and tenofovir as well as aminoglycoside antibiotics. Live vaccines against viruses like varicella and zoster should not be given while a patient is being treated with valacyclovir.
Acyclovir May Interact With Other Medications
An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well. To help prevent interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs youre taking.
To find out how this drug might interact with something else youre taking, talk to your doctor or pharmacist.
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
This drug comes with several warnings.
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What Other Drugs Will Affect Acyclovir
Acyclovir can harm your kidneys, especially if you also use certain medicines for infections, cancer, osteoporosis, organ transplant rejection, bowel disorders, high blood pressure, or pain or arthritis .
Other drugs may interact with acyclovir, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.
More Common Side Effects
Some of the more common side effects of acyclovir oral tablet include:
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always speak with your doctor or pharmacist about dosages that are right for you.
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How Does This Medication Work What Will It Do For Me
Acyclovir belongs to the family of medications known as antivirals. Acyclovir is used to treat and prevent genital herpes. It is also used for the acute treatment of herpes zoster and varicella . All these infections are caused by viruses. Acyclovir helps healing by stopping the virus from multiplying and spreading to nearby healthy cells.
This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.
Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.
Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.
How Should This Medicine Be Used
Acyclovir comes as a tablet, a capsule, and a suspension to take by mouth. It also comes as a delayed-release buccal tablet to apply to the upper gum of the mouth. The tablets, capsules, and suspension are usually taken with or without food two to five times a day for 5 to 10 days, starting as soon as possible after your symptoms begin. When acyclovir is used to prevent outbreaks of genital herpes, it is usually taken two to five times a day for up to 12 months. The delayed-release buccal tablet is usually applied with a dry finger as a one-time dose within 1 hour after itching, redness, burning or tingling cold sore symptoms begin but before the cold sore appears. Take or use acyclovir at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take or use acyclovir exactly as directed. Do not take or use more or less of it or take it more often or for a longer time than prescribed by your doctor.
Do not chew, crush, suck, or swallow the delayed-release buccal tablets. Drink plenty of liquids, if you have a dry mouth while using the delayed-release buccal tablets.
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Other Antiviral Agents Used In Herpes Infections
Valaciclovir is a prodrug of aciclovir and has better bioavailability. It can also be used to treat HSV and HZV. It is used to prevent CMV infection following an organ transplant. Usual doses are:
- HZV: 1 g three times daily for 7 days
- HSV: 500 mg twice daily for 5 days.
Famciclovir is used for HSV and HZV. The usual doses are:
- HZV: 500 mg three times daily for 10 days
- HSV: 125250 mg three times daily for 5 days
- Suppression longterm: 250 mg twice daily
- Recurrent HSV of lips: a single dose of 500 mg at first signs of blistering
- Recurrent genital HSV: 100 mg twice daily for 1 day at first signs of blistering.
Other Uses For This Medicine
Acyclovir is also sometimes used to treat eczema herpeticum to treat and prevent herpes infections of the skin, eyes, nose, and mouth in patients with human immunodeficiency virus , and to treat oral hairy leukoplakia .
This medication may be prescribed for other uses ask your doctor or pharmacist for more information.
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Is Acyclovir Or Valacyclovir More Effective
Acyclovir and valacyclovir were compared in the treatment of first episodes of genital herpes infections in an international double-blind, randomized trial. Acyclovir was dosed five times daily, and valacyclovir was dosed only twice daily. It found no clinically significant difference in the lesion healing time, duration of pain, or time to loss of all symptoms. Given that, valacyclovir offers the advantage of twice-daily dosing. This decreases pill burden and increases the likelihood that patients will take the regimen as prescribed until completion. Your doctor will determine what is best to treat a genital herpes infection, but twice-daily dosing may offer an advantage for valacyclovir.
In another randomized, double-blind clinical trial, acyclovir and valacyclovir oral tablet doses were compared for a herpes zoster infection, otherwise known as shingles. The results of this study showed valacyclovir significantly accelerated the resolution of pain associated with a shingles rash. While the rash itself resolved in similar times with either treatment regimen, there were fewer ocular complications in those treated with valacyclovir. Another significant advantage for valacyclovir in this study is that it only needed to be dosed three times per day as compared to five times per day for acyclovir. Ultimately, only your prescriber can determine which treatment option is best for you with an active herpes zoster infection.