Valovir-500

Valaciclovir hydrochloride.

Each film coated tablet contains Valaciclovir Hydrochloride Monohydrate 583.80 mg equivalent to Valaciclovir 500 mg.

Pharmacology: Pharmacodynamics: Valaciclovir is rapidly converted to Aciclovir which has demonstrated antiviral activity against herpes simplex virus types 1 (HSV-1) and 2 (HSV- 2) and varicella-zoster virus (VZV) both in vitro and in vivo.
The inhibitory activity of Aciclovir is highly selective because of its affinity for the enzymethymidine kinase (TK) encoded by HSV and VZV. This viral enzyme converts Aciclovir into Aciclovir monophosphate, a nucleotide analogue. The monophosphate is further converted into diphosphate by cellular guanylate kinase and into triphosphate by a number of cellular enzymes in vitro, Aciclovir triphosphate stops replication of herpes viral deoxyribonucleic acid (DNA). This is accomplished in the following 3 ways: competitive inhibition of viral DNA polymerase, incorporation and terminate of the growing viral DNA chain, and inactivation of the viral DNA polymerase.
Pharmacokinetics: Valaciclovir is rapidly absorbed from the gastrointestinal tract after oral doses, and is rapidly converted to Aciclovir and valine by first-pass intestinal hepatic metabolism. The bioavailability of Aciclovir after Valaciclovir administration is reported to be 45% and peak plasma concentrations of Aciclovir are achieved after 1.5 hours. Valaciclovir is eliminated mainly as Aciclovir and its metabolite 9-carboxymethoxymethylguanine; less than 1% of a dose of Valaciclovir is excreted unchanged in the urine.

Herpes zoster (Shingles).
Genital herpes: For the treatment or suppression of genital herpes in immunocompetent individuals with and for the suppression of recurrent genital herpes in HIV-infected individuals.
Cold sores (Herpes labialis).

Recommended dose: Herpes zoster: 1 g orally 3 times daily for 7 days. Therapy should be initiated at the earliest sign or symptoms of Herpes zoster and is most effective when started within 48 hours of the onset of zoster rash.
Genital herpes: Initial episodes: 1 g twice daily for 10 days. Therapy was most effective when administered within 48 hours of the onset of TTP signs and symptoms.
Recurrent episodes: 500 mg twice daily for 3 days.
Suppressive therapy: 1 g once daily in patients with healthy immune function. In patients with a history of 9 or fewer recurrences per year, and alternative dosage is 500 mg once daily.
HIV-infected patients in HIV-infected patients with CD4 cell count at least 100 cells/mm³, the recommended dosage of Valaciclovir for chronic Suppressive therapy of Recurrent Genital herpes is 500 mg twice daily.
Reduction of transmission: The recommended dosage of Valaciclovir for Reduction of transmission of genital herpes in patients with a history of 9 or fewer recurrences per year is 500 mg once daily for the source partner.
Cold sores (herpes labialis): 2 g twice daily for 1 day, taken about 12 hours apart.
Mode of administration: Administration by oral. Valaciclovir may be given without regards to meals.

Symptoms: Precipitation of Aciclovir in renal tubules may occur and the solubility (2.5 mg/ml) is exceeded in the intratubular fluid.
Treatment: In the event of acute renal failure and anuria, the patient may benefit from hemodialysis until renal function is restored.

Known Hypersensitivity or intolerance to valaciclovir, aciclovir or any components of the formulation.

Hematologic effects: Thrombotic thrombocytopenic purpura/haemolytic uremic syndrome (sometimes fatal) reported in patients with advanced HIV infection and in allogenic bone marrow or renal transplant recipients receiving high dosage (8 g daily).

Pregnancy: Category B.
Lactation: Aciclovir distributed into human milk following oral administration of Valaciclovir.
Use Valaciclovir with caution.

Adverse reactions are listed as follows: Cardiovascular: Hypertension, tachycardia.
CNS: Depression, dizziness, headache, aggressive behaviour, agitation, ataxia, coma, confusion, decreased consciousness, dysarthria, encephalopathy, mania, psychosis, including auditory and visual hallucinations, seizures, tremors.
Dermatologic: Rash, alopecia, erythema multiforme, rashes, including photosensitivity.
GI: Abdominal pain, nausea, vomiting, diarrhea.
Hematologic: Aplastic anemia, leukocytoclastic vasculitis, thrombocytopenia, TTP/HUS.
Hepatic: Liver enzyme abnormalities.
Hypersensitivity: Acute hypersensitivity reactions, including anaphylaxis, angioedema, dyspnea, pruritus, rash and urticaria.
Ophthalmic: Visual abnormalities.
Renal: Elevated creatinine, renal failure.
Miscellaneous: Facial edema.

Antacids: Concomitant use of Valaciclovir and aluminium- or magnesium-containing antacids does not affect the pharmacokinetics of Aciclovir dosage adjustments are necessary.
Cimetidine: Concomitant use of Valaciclovir and Cimetidine may increase peak plasma concentrations and AUC of Aciclovir. This pharmacokinetics interaction is not considered clinically important in patients with normal renal function; no dosage adjustment are necessary in these patients.
Probenecid: Concomitant use of Valaciclovir and Probenecid may increase peak plasma concentrations and AUC of Aciclovir. This pharmacokinetics interaction is not considered clinically important in patients with normal renal function; no dosage adjustment are necessary in these patients.
Digoxin: Concomitant use of Valaciclovir and Digoxin does not affect the pharmacokinetics of Aciclovir or Digoxin dosage adjustment are necessary.
Thiazide diuretics: Concomitant use of Valaciclovir and Thiazide diuretics does not affect the pharmacokinetics of Aciclovir; no dosage adjustments are necessary.

Store below 30°C.

Antivirals

J05AB11 - valaciclovir ; Belongs to the class of nucleosides and nucleotides excluding reverse transcriptase inhibitors. Used in the systemic treatment of viral infections.

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