Herpes Drugs

What is Valacyclovir?

Valacyclovir is an antiviral drug used for the treatment of viral infections caused by herpes virus. Herpes is a none-curable viral infection presently with any medication. Valacyclovir efficiently controls a variety of symptoms related to herpes infection but cannot cure. Valacyclovir is available on prescription. It is highly recommended by physicians due to its excellent efficacy and safety profile. Valacyclovir is manufactured in USA market after approval from USFDA by Ranbaxy Laboratories which is a giant in generic formulations.

Ingredients of Valacyclovir formulation: Valacyclovir hydrochloride is a prodrug and a main ingredient in its formulation. Its formulation contains various fillers like carnauba wax, colloidal silicon dioxide, crospovidone, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, and TiO₂. All these ingredients are inactive which are added to make up the volume of the formulation and its preservation.

Available formulations: Valacyclovir is available in tablet formulation in two different strengths 500mg and 1g. Valacyclovir oral suspension is prepared extemporaneously by using the tablet formulation in different dosage strengths like 25 mg/mL or 50 mg/mL for pediatric population.

How does Valacyclovir work?

Valacyclovir hydrochloride is a prodrug which means it is actually inactive and is converted into an active form in the body by various enzymes. Valacyclovir HCl is converted more specifically by esterases via hepatic first-pass metabolism into acyclovir and amino acid valine. This acyclovir is then converted into acyclovir monophosphate by a viral enzyme thymidine kinase (TK). The acyclovir monophosphate is further converted into acyclovir bi-phosphate and then into acyclovir triphosphate by various cellular enzymes. This acyclovir triphosphate form acts on viral DNA replication process in three different steps. Firstly, it competitively inhibits viral DNA polymerase; secondly, it terminates the growing viral DNA polymerase chain by incorporating itself in this chain, and thirdly and finally it inactivates viral DNA polymerase. So, it helps in inhibition of further nucleotides addition to this viral strand and thus viral growth is blocked. Valacyclovir shows better antiviral activity in herpes infections than varicella because of its more effective phosphorylation via viral thymidine kinase.

Side effects and safety profile of Valacyclovir: Valacyclovir have shown various side effects but these are usually non-serious and easily tolerable. This list includes constipation, diarrhea, headache, and stomach upset. There are some moderate side effects like bloody urine, confusion, itching, fever, yellowish skin, and rash. If you feel such side effects, you must immediately consult your physician to minimize their impacts.

Indication/Usage of Valacyclovir: Valacyclovir is used in various viral infections. The list of indications include various herpes infections like HSV1 which causes cold sores, HZV responsible for shingles, VZV often responsible for chicken pox and shingles both, HSV2 which causes genital herpes (prophylactic and treatment both), and in cytomegalovirus prevention. Valacyclovir actually helps in recurrent, suppressive, and reduction of transmission of herects.pes infection. It is also used in renal disease patients with precautions to avoid acute renal failure. You must take it with precautions and as prescribed by physician to get best results with minimum side effects.

What is Acyclovir?

Acyclovir is antiviral class drug used in various herpes virus infections like oral herpes, genital herpes, chicken pox, shingles etc. Chemically, Acyclovir is known as acycloguanosine.  It is proven to be safe and very effective drug and highly researched by research professionals especially for herpes infections. FDA has approved Acyclovir in 1982 for its antiviral properties. It is recommended by physicians to take Acyclovir as prescribed to get best possible results. Acyclovir pregnancy registry is established in 1984 by GlaxoSmithKline.

Ingredients of Acyclovir formulation: Acyclovir is a main ingredient (prodrug) in its various formulations. It also contains various excipients (inactive ingredients) depends upon its type of formulation.

Available formulations: Acyclovir is available in various formulations as below:

• Tablets: (strengths: 200mg, 400mg, 800mg, and 1gm), for oral administration.
• Capsules: (strengths: 200mg, 400mg, 800mg, and 1gm), for oral administration.
• Cream (5%), for topical administration.
• Intravenous injection (25 mg/mL),
• Ophthalmic ointment (3%).

How does Acyclovir work?

Acyclovir is a broad spectrum antiviral class drug. It is highly effective against herpes simplex virus 1 (HSV1) responsible for cold herpes and herpes simplex virus 2 (HSV2) responsible for genital herpes, varicella-zoster virus (VZV), and epstein-barr virus (EPV). These herpes viruses essentially need nucleoside analogues for their natural growth and multiplication. Acyclovir is structurally similar to such nucleoside. These viruses themselves exchange Acyclovir into its active form Acyclovir monophosphate by the viral enzyme thymidine kinase (TK). This Acyclovir monophosphate is much more active (~3000 times) than cellular thymidine kinase in phosphorylation process. Acyclovir monophosphate is then further transformed into bi-phosphate and then triphosphate by numerous cellular enzymes via phosphorylation. This Acyclovir triphosphate form is a real candidate and plays biggest role in DNA replication inhibition process. This acts in three different steps as firstly, it competitively inhibits viral DNA polymerase; secondly it terminates the growing viral DNA polymerase chain by incorporating itself in this chain, and finally inactivates viral DNA polymerase. So, there will no further nucleotides addition into this viral strand and thus viral growth is stopped by Acyclovir.

Side effects and safety profile of Acyclovir: There are some common and non-serious side effects are associated with Acyclovir like diarrhea, headache, nausea, and vomiting. There are some occasional and moderately severe side effects such as confusion, constipation, dizziness, gastric pain, rash, and sore throat are also reported with Acyclovir. There are some serious but rare side effects are also associated with Acyclovir usage such as anaphylactic reactions, hepatitis, leukopenia, seizures, and Stevens-Johnson syndrome. Acyclovir may also cause hallucinations when it is used in higher than prescribed dosage. Overall, it is very safe drug with very tolerable side effects profile.

Indication/Usage of Acyclovir:

Acyclovir is indicated for the treatment of various infections caused by herpes viruses. The indication list of herpes virus includes HSV1 (usually responsible for oral herpes), HSV2 (usually responsible for genital herpes), VZV (usually responsible for chicken pox and shingles), EBV (usually responsible for mononucleosis infection, Burkitt’s lymphoma, nasopharyngeal cancer, oral hairy leukoplakia, and transformation of B cells), and cytomegalovirus (CMV-usually responsible for mononucleosis and hepatitis). Acyclovir is also used in infections caused by herpes simplex encephalitis, herpes simplex blepharitis, and herpes simplex keratitis. Acyclovir is also used for prophylaxis of genital herpes. Acyclovir is usually indicated for immuno-compromised patients. So, with broad spectrum antiviral properties and pretty good safety profile, Acyclovir could be a drug of your choice which is available in various formulations as per your requirements.

What is Famvir?

Famvir is classified as antiviral drug used especially in herpes virus infections. It contains famciclovir as its main ingredient. Famvir is manufactured and marketed by Novartis Ltd., a Switzerland based huge pharmaceutical company. Famvir does not guarantee to cure herpes infections but it can minimize herpes impact to a significant level than other antiviral agents. It is also available in generic form manufactured by TEVA pharmaceuticals and Mylan pharmaceuticals in different dosage strengths.

Ingredients of Famvir formulation: Famvir contains famciclovir as a main pharmaceutical ingredient in its formulation. Famvir formulation contains various excipients like hydroxypropyl cellulose, hydroxypropyl methylcellulose (HPMC), lactose, Mg stearate, polyethylene glycols (PEG), Na starch glycolate, and titanium dioxide (TiO₂). These ingredients have different properties like binder, preservative, fillers etc. and are used in formulation to make up the volume. These are inactive and proven to be safe for human body.

Available formulations: Famvir is available in film coated tablet formulation for oral administration in three different strengths 125 mg, 250 mg, and 500 mg. These different strengths are used in different type of therapies with different level of infections. Famvir should be stored at 25^oC, or within a range of 15-30°C.

How does Famvir work?

Famciclovir, a main ingredient, actually is a prodrug of antiviral agent penciclovir. Once famciclovir is converted into penciclovir in human body, it is than further converted into penciclovir monophosphate by the viral enzyme thymidine kinase in virus infected cells. This penciclovir monophosphate is finally converted into penciclovir triphosphate by various cellular enzymes. The penciclovir triphosphate is actually structurally similar to nucleosides used in DNA replications by these viruses for their growth. Now, penciclovir triphosphate starts inhibiting DNA polymerase by competitively exchanging with deoxyguanosine triphosphate.  This results into use of the penciclovir triphosphate in viral DNA polymerase, which results in inactivated viral DNA polymerase, and inhibited growth of viruses. The more beneficial effects of famciclovir are because of its longer duration of action against viruses.

Side effects and safety profile of Famvir: There are some common side effects associated with Famvir. This list includes gastric side effects like nausea, vomiting, diarrhea, and gas problems. The other common side effects are headache, fatigue, and rashes. Some serious and rare side effects caused by Famvir include thrombocytopenia, neutropenia, and skin reactions.

Indication/Usage of Famvir:

Famvir is used in various viral infections and more specifically herpes virus related infections as below:

• Recurrent genital and oral herpes infections in HIV patients
• Suppression of recurrent genital herpes,
• Cold sores (Recurrent herpes labialis)
• Shingles (Herpes zoster)

Famvir should not be used by immuno-compromised patients like diabetics, renal replacement therapy patients and other than those who are on treatment for recurrent oral or genital herpes HIV-infected patients. Additional benefits of famciclovir include relief from pain, burning, itching, tingling, and sores associated with herpes infections.

What is Valtrex?

Valtrex is an antiviral class drug used for the treatment of viral infections caused by herpes simplex virus (HSV), herpes labialis virus (HLV), and herpes zoster virus (HZV). Herpes is actually a none-curable virus at this time with any medication and so with Valtrex; however Valtrex diminishes various symptoms of herpes infection very efficiently. Valtrex is manufactured and marketed by GlaxoSmithKline. It is also available in generic formulation in USA market which is manufactured by Ranbaxy Laboratories.

Ingredients of Valtrex formulation: Valtrex contains Valacyclovir HCl as main ingredient in its formulation. It also contains excipients like carnauba wax, colloidal SiO₂, crospovidone, povidone, hypromellose, Mg stearate, microcrystalline cellulose (MCC), polyethylene glycol (PEG), polysorbate 80, and TiO₂.

Available formulations: Valtrex is available in orally administrable formulation as caplets. Caplets are formulation similar to capsules but actually are tablets. Valtrex is available in 500mg and 1gm dosage strengths.

Valacyclovir oral suspension can also be prepared extemporaneously by using caplets formulation. This is prepared in different dosage strengths like 25 mg/mL or 50 mg/mL. This suspension is used in pediatrics where pills administration is not possible.

How does Valtrex work?

Valtrex contains Valacyclovir HCl as main ingredient. Valacyclovir HCl is actually a prodrug which means it is an inactive from and is converted into an active form in the body by enzymes. Valacyclovir HCl is converted by esterases via hepatic first-pass metabolism into active form acyclovir and amino acid valine as well. This acyclovir is then converted into acyclovir monophosphate by a viral enzyme thymidine kinase. The acyclovir monophosphate is further converted into acyclovir triphosphate by some cellular enzymes. This acyclovir triphosphate form actually acts on viral DNA replication process in three different steps. First of all it competitively inhibits viral DNA polymerase procedure; then it stops the growing viral DNA polymerase chain by fitting itself in the developing chain, and finally it inactivates viral DNA polymerase. This entire procedure stops further addition of nucleotides to this viral strand. Thus it stops further growth of viruses. The acyclovir shows better antiviral activity against herpes as compared to varicella because of its more effective phosphorylation via viral thymidine kinase.

Side effects and safety profile of Valtrex: There are some very common side effects reported about Valtrex. These are abdominal pain, headache, and nausea. These side effects occur quite frequently, however, these are non-serious and easily treatable. There are some serious side effects are also reported as thrombotic thrombocytopenic purpura, acute renal failure, and CNS related side effects like agitation, confusion, hallucinations, and seizures. If you experience any of above serious kind of side effects, you should immediately consult your physician.

Indication/Usage of Valtrex:

Valtrex is indicated for various viral infections in different patients as below:

• Herpes labialis (Causes cold sores),
• Oral and genital herpes simplex (for prophylactic as well as treatment use – initial, recurrent, suppressive, and transmission reduction therapies),
• Treatment in immunocompetent patients (initial or recurrent episode),
• Suppression in immunocompetent or HIV-infected patients,
• HSV transmission reduction from patients with recurrent infections,
• Herpes zoster (shingles),
• Chickenpox,
• Prevention of cytomegalovirus disease after organ transplantation procedure, and
• Prophylactic use in suspected herpes B virus population.

Besides above indications, it can be used in renal disease patients, however, it must be used as prescribed by physician to avoid acute renal failure and other side effects.

What is Zovirax?

Zovirax is an antiviral drug used for the treatment of viral infections like herpes. Zovirax is a synthetic nucleoside analogue which is very effective against herpes viruses. Herpes is none-curable presently with any medication and so with Zovirax; however Zovirax diminishes various symptoms of herpes infection very effectively. Zovirax is a registered brand of GlaxoSmithKline which is one of the giant pharmaceutical organizations. Its active ingredient Acyclovir is approved by FDA in 1982.

Ingredients of Zovirax formulation:

Zovirax contains Acyclovir as a main ingredient (prodrug) in its various formulations. It also contains various inactive ingredients (excipients) depending upon type of formulation.

Available formulations: Zovirax is available in various oral and topical formulations in different strengths as below:

• Capsules: 200 mg,
• Cream 5%,
• Injection (iv): 25 mg/ml,
• Ointment 5%,
• Ophthalmic ointment (3%),
• Powder for injection: 500 and 1000 mg,
• Suspension: 200 mg/5 ml,
• Tablets: 200 mg, 400 mg, 800 mg, and 1 gm.

How does Zovirax work?

Zovirax is a broad spectrum antiviral agent which is effective against herpes simplex 1 and 2 (responsible for cold sores and genital herpes), varicella-zoster, and epstein-barr virus. These viruses actually need nucleoside analogues for their growth and multiplication. Acyclovir, main ingredient of Zovirax, is structurally similar to nucleoside. These viruses themselves convert Acyclovir into its active form Acyclovir monophosphate by viral enzyme thymidine kinase. This monophosphate form is much more active (around 3000 times) than cellular thymidine kinase for phosphorylation. This monophosphate form is further converted into triphosphate by several cellular enzymes via phosphorylation. This Acyclovir triphosphate form actually stops viral DNA replication in three steps. Firstly it competitively inhibits viral DNA polymerase; secondly it terminates the growing viral DNA polymerase chain by incorporating itself in this chain, and thirdly inactivates viral DNA polymerase. So, finally no further nucleotides add to this viral strand and thus viral growth is stopped with the help of Acyclovir.

Side effects and safety profile of Zovirax: Zovirax have shown some common and non-serious side effects like diarrhea, headache, nausea, and vomiting. It may also show hallucinations if used in high dosage. There are some infrequent side effects are also reported as confusion, constipation, dizziness, gastric pain, rash, and sore throat. It may also cause anaphylactic reactions, hepatitis, leukopenia, seizures, and Stevens-Johnson syndrome; however, these are rarely seen side effects. Overall, it is quite safe drug with tolerable side effects profile.

Indication/Usage of Zovirax: Zovirax is indicated for the treatment of infections caused by herpes simplex viruses (HSV), varicella zoster virus (VZV), and epstein-barr virus (EBV). Zovirax can be used in various diseases like genital chicken pox, cold sores (caused by herpes simplex labialis), shingles, herpes simplex encephalitis, herpes simplex blepharitis, and herpes simplex keratitis (ocular herpes). So, Zovirax is helpful in all such herpes infections. Zovirax is also used for prophylaxis as well as treatment of genital herpes simplex. Zovirax is indicated for acute chickenpox and acute mucocutaneous in immuno-compromised patients as well. So, if you have any of above disease, you can use Zovirax as it is pretty safe drug and effective drug and available in various formulation as per your needs.