How do the current herpes & treatments work?
Mode of Action
The major drugs that doctors use to treat the herpes simplex virus (HSV) are antiviral agents called nucleosides and nucleotide analogues. They work by blocking reproduction of the herpes simplex virus.
These drugs are oral medications called acyclovir (also spelled as aciclovir in the UK and other counties), valacyclovir and famciclovir. Acyclovir, Valacyclovir and famcyclovir can lessen the severity of a primary outbreak, reduce the time it takes genital herpes outbreaks to heal and can decrease the number of days of symptoms and days the virus is transmissible.
There are other antivirals similar to these drugs that are available in topical and intravenous formulations, but they are generally used to treat different viruses.
These antiviral medications are most effective when taken early in the course of an outbreak, when you first feel the tingling and pain. If you have a lot of outbreaks (more than 6 a year), studies show that taking antiviral medication daily to suppress the virus can reduce the frequency and duration of recurrent outbreaks.
Herpes medications available
Acyclovir (also known as Aciclovir or Zovirax)
This was the first prescription pill introduced for genital herpes. The brand name for this drug is Zovirax, however, it is now a generic and as a result is the cheapest out of all three herpes medications. Acyclovir has been approved for the treatment of initial and recurrent genital herpes episodes.
Recommended Dose
Acyclovir needs to be taken the most frequently out of all of the herpes medications, but is the least expensive. It should be taken no less than 3 to 5 times a day to be effective. Like all of the herpes medications, it should be started at the first sign of symptoms, such as tingling or itching, to be most effective.
Valacyclovir (Valtrex)
Valacyclovir’s brand name is Valtrex. It is a prodrug of acyclovir, which means that it converts into the active drug acyclovir once inside the body and is utilized and absorbed more efficiently. This doesn’t make this drug more effective than acyclovir, it just means you need to take less of it to achieve the same result.
Valtrex has been approved for the treatment and suppression of genital herpes. This means that it can be prescribed as a daily medication to help stop outbreaks from coming back. However, it is normally only prescribed in this way if the outbreaks are very frequent, such as 6 or more per year. The majority of people will be prescribed to take Valtrex only when they are experiencing symptoms.
Recommended Dose
To prevent an outbreak happening Valtrex is usually taken once daily. When it is used to treat the active symptoms only, a less concentrated dose of 2 tablets per day can be prescribed for 3 to 10 days. Once again, the course should be started within the first 24 hours of noticing any signs or symptoms to be effective.
Famcyclovir (Famvir)
Famcyclovir’s brand name is Famvir. It is a prodrug of a different antiviral called penciclovir, which is very similar to Valacyclovir. Famcyclovir has been approved for the treatment and suppression of genital herpes, however, its efficacy has not been established in regards to treatment of the first initial outbreak. It can be prescribed as a daily medication to help stop outbreaks from coming back, however, it is normally only prescribed in this way (as a suppressive) if the outbreaks are very frequent, such as 6 or more per year.
Recommended Dose
Famcyclovir needs to be taken the least frequently out of all of the herpes medications, but is more expensive. It should be taken no less than two times a day to be effective for genital herpes, but only once a day for cold sores. Like all of the herpes medications, it should be started at the first sign of symptoms, such as tingling or itching, to be most effective.
Do they all work the same?
Effectiveness and Dose
Current research has not found any major differences in the safety or effectiveness of these three antiviral drugs. All three medications can be taken at the first sign of an outbreak, or taken daily to help suppress the virus and prevent a recurrence of symptoms.
There is limited data on how effective famciclovir is during the first primary outbreak, and for this reason acyclovir or valacyclovir are normally prescribed during the first genital herpes outbreak.
Valacyclovir (Valtrex) needs to be taken less often than Acyclovir because it is absorbed more efficiently by the body. This makes it more convenient but it is also more expensive. Valacyclovir is the only one of these three medications that has been proven to reduce the rate of transmission to an uninfected partner, if taken daily. Valacyclovir may help to reduce the incidence of Viral Shedding by approximately 40%.
Famcyclovir is generally the most convenient of the three medications because it needs to be taken least often, but typically has the highest price tag.
Safety
All of the medications are generally safe in most circumstances but may occasionally have adverse side-effects. To help reduce any side-effects the medication should be taken along with food and will likely reduce with each successive dose.
Many people do not experience any side-effects, and they are most common when taking the medication daily as a suppressive. These side-effects are normally not severe and could include nausea, diarrhea, headache, stomach aches, flu symptoms or sore throat.
More severe side-effects such as alopecia (hair loss) and seizures have been reported but are rare. You can see a full list of these below. People with kidney disease are normally put on a reduced dose which is monitored closely by a physician. All three medications will normally only be prescribed during pregnancy if the potential risk to the foetus outweighs the benefit of taking the medication, as the safety of these medications during pregnancy has not been established.
Herpes Medication Comparison Chart
Below is a comparison chart designed to help you assess the cost and requirements of prescription herpes drugs.
Warning
The chart contains only a general dosage guideline as outlined in the drug manufacturer’s prescribing information. PLEASE NOTE that this guide is merely to demonstrate the possible differences in convenience of taking each treatment and IS NOT to be used as a recommended dosage under any circumstance.
These medications are only available by prescription. You must consult a doctor for information about using these drugs for your particular situation.
Prices are a rough estimate and will vary greatly depending on the particular retail market and source. If you are covered by medical insurance, some of these prices may be subsidized dramatically.
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Herpes Medication: |
Valtrex® |
Zovirax® |
Famvir® |
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$203.28 per 30 tablets (500mg) Typically treats up to 5 outbreaks. The above figure is based on typical Episodic use, i.e., the pills are taken only when you have an outbreak. $362.55 per 30 tablets (1g)
The above figure is based on typical Suppressive use – i.e., the pills are taken every day to prevent an outbreak. |
$90.98 per 90 tablets (200mg) Typically treats 3 outbreaks. The above figure is based on typical Episodic use, i.e., the pills are taken only when you have an outbreak. $203.03 per 90 tablets (400mg)
The above figure is based on typical Suppressive use – i.e., the pills are taken every day to prevent an outbreak. |
$351.46 per 30 tablets (500mg) Typically treats up to 7 outbreaks. The above figure is based on typical Episodic use, i.e., the pills are taken only when you have an outbreak. $175.01 per 30 tablets (250mg)
The above figure is based on typical Suppressive use – i.e., the pills are taken every day to prevent an outbreak.
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Take VALTREX® by mouth strictly and only as directed by your health care professional. Manufacturer’s recommended dose for recurrent Genital Herpes infections:
Start as soon as symptoms begin, may not be effective if started more than 24 hours after the onset of symptoms.
Please consult your doctor for your specific dosage. |
Take ZOVIRAX® by mouth strictly and only as directed by your health care professional. Manufacturer’s recommended dose for recurrent Genital Herpes infections:
Start as soon as symptoms begin, may not be effective if started more than 24 hours after the onset of symptoms.
Please consult your doctor for your specific dosage. |
Take FAMVIR® by mouth strictly and only as directed by your health care professional. Manufacturer’s recommended dose for recurrent Genital Herpes infections: Episodic: 1000mg twice daily for 1 day. Start as soon as symptoms begin, may not be effective if started more than 6 hours after the onset of symptoms.
Please consult your doctor for your specific dosage. |
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General side effects that may, but not always, occur: Nausea, vomiting, diarrhea, constipation, or abdominal pain; headache; dizziness; or tremors.
General: Facial edema (facial swelling), hypertension (high blood pressure), tachycardia (fast heart rate). Allergic: Acute hypersensitivity reactions including anaphylaxis (a life-threatening type of allergic reaction), angioedema (swelling similar to hives), dyspnea (shortness of breath), pruritus (itching), rash, and urticaria (hives). Nervous: Aggressive behavior; agitation; ataxia (loss of coordination); coma; confusion; decreased consciousness; dysarthria (disturbance of speech); encephalopathy (degenerative brain disease); mania; and psychosis (irrational thoughts and fears), including auditory and visual hallucinations; seizures, tremors. Eye: Visual abnormalities. Gastrointestinal: Diarrhea. Hepatobiliary Tract and Pancreas: Liver enzyme abnormalities, hepatitis. Renal: Elevated creatinine, renal failure (kidney failure). Hematologic: Thrombocytopenia (low platelet count), aplastic anemia (a lower than normal number of red blood cells), leukocytoclastic vasculitis (a condition that causes inflammation of the small vessels), TTP/HUS (a disease characterised by anemia, kidney failure and a low platelet count). Skin: Erythema multiforme (a skin disease that causes lesions and redness), rashes including photosensitivity (sensitivity to light), alopecia (loss of hair).
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General side effects that may, but not always, occur: Nausea, vomiting, diarrhea, decreased appetite, or abdominal pain; a headache or light headedness; or joint pain.
General: Anaphylaxis (a life-threatening type of allergic reaction), angioedema (swelling similar to hives), fever, headache, pain, peripheral edema (abnormal buildup of fluid in the ankles, feet, and legs). Nervous: Aggressive behavior, agitation, ataxia (loss of coordination), coma, confusion, decreased consciousness, delirium (severe confusion), dizziness, dysarthria (disturbance of speech), encephalopathy (degenerative brain disease), hallucinations, paresthesia (burning, prickling, tingling, or creeping on the skin), psychosis (irrational thoughts and fears), seizure, somnolence (drowsiness; sleepiness), tremors. These symptoms may be marked, particularly in older adults or in patients with renal (kidney) impairment. Digestive: Diarrhea, gastrointestinal distress (upset stomach and intestines), nausea. Hematologic and Lymphatic: Anemia (a lower than normal number of red blood cells), leukocytoclastic vasculitis (a condition that causes inflammation of the small vessels), leukopenia (abnormally low white blood cell count), lymphadenopathy (swelling of the lymph nodes), thrombo-cytopenia (when the number of platelets is abnormally low, sometimes associated with abnormal bleeding). Hepatobiliary Tract and Pancreas: Elevated liver function tests, hepatitis, hyperbilirubinemia (elevated levels of bilirubin within the blood), jaundice (yellowing of the skin and eyes). Musculoskeletal: Myalgia (muscle pain) Skin: Alopecia (loss of hair), erythema multiforme (a skin disease that causes lesions and redness), photosensitive rash (sensitivity to light), pruritus (itching), rash, Stevens-Johnson syndrome (a severe allergic reaction that can result in skin blistering, fever, and eye damage. It is potentially fatal, and can also cause blindness and disfigurement), toxic epidermal necrolysis (a life-threatening skin disorder characterized by blistering and peeling of the top layer of skin), urticaria (hives). Special Senses: Visual abnormalities. Urogenital: Renal failure (kidney failure), elevated blood urea nitrogen, elevated creatine, hematuria (blood in the urine).
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General side effects that may, but not always, occur: Headache, nausea, vomiting, diarrhea, fatigue, pruritus (itching).
Nervous System: Headache, Paresthesia (burning, prickling, tingling, or creeping on the skin), Migraine Gastro-intestinal: Nausea, Diarrhea, Vomiting, Flatulence, Abdominal Pain Body as a Whole: Fatigue Skin and Appendages: Pruritus (itching), Rash Reproductive Female: Dysmenorrhea (painful menstruation) Adverse events that have been reported during post-approval of FAMVIR®: urticaria (hives), hallucinations and confusion — including delirium (severe confusion), disorientation, confusional state, occurring predominantly in the elderly.
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If taken with certain other drugs, the effects of either could be increased, decreased, or altered. Tell your doctor of any over-the-counter or prescription medication you may take including cimetidine or probenecid.
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If taken with certain other drugs, the effects of either could be increased, decreased, or altered. Tell your doctor of any over-the-counter or prescription medication you may take in conjunction with ZOVIRAX®.
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If taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining with probenecid (Benemid), a drug used to treat gout (a type of arthritis).
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VALTREX® is This drug is not proven to work if taken more than 24 hours after the onset (beginning) of symptoms.
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ZOVIRAX® only works while you are taking the drug and will not work when you stop taking it. This drug is not proven to work if taken more than 24 hours after the onset (beginning) of symptoms.
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FAMVIR® only works while you are taking the drug and will not work when you stop taking it. This drug is not proven to work if taken more than 6 hours after the onset (beginning) of symptoms.
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Tell your doctor if you have any kidney disease, blood disorders or if you have any allergies. VALTREX® should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus. VALTREX® should be administered to a nursing mother with caution and only when indicated. Patients should be advised to maintain adequate hydration. Do not stop VALTREX® or change your dosage without talking to your healthcare provider.
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Tell your doctor if you have any kidney disease, blood disorders or if you have any allergies. ZOVIRAX® should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus. ZOVIRAX® should be administered to a nursing mother with caution and only when indicated. Patients should be advised to maintain adequate hydration. Do not stop ZOVIRAX® or change your dosage without talking to your healthcare provider. Also tell your prescriber or health care professional if you are a frequent user of drinks with caffeine or alcohol, if you smoke, or if you use illegal drugs. These may affect the way ZOVIRAX® works.
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Tell your doctor if you have any kidney disease, blood disorders or if you have any allergies. FAMVIR® (famciclovir) is contraindicated in patients with known hypersensitivity to the product, its components, and Denavir® (penciclovir cream). FAMVIR® should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. FAMVIR® should be administered to a nursing mother with caution and only when indicated. Patients should be advised to maintain adequate hydration. Do not stop FAMVIR® or change your dosage without talking to your healthcare provider.
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*Retail prices provided are based on findings by the Department of Health and Human Services regarding retail pharmacy prices of brand-name drugs for cash-paying customers. Actual prices may vary.
