Xynovir (Tenofovir Disoproxil Fumarate)

Therapeutic Group: Anti Viral Hepatitis B Medication

Xynovir: Each tablet contains Tenofovir Disoproxil Fumarate INN 300 mg.

Tenofovir Disoproxil Fumarate, an acyclic nucleotide analogue of adenosine monophosphate is a prodrug of Tenofovir. It shows activity against HBV polymerase and HIV reverse transcriptase after phosphorylation to the active diphosphate form. Tenofovir diphosphate inhibits viral polymerases (reverse transcriptase) by direct competing with the natural substrate deoxyribonucleotide and by causing DNA chain termination after its incorporation into viral DNA.

Tenofovir is indicated for the treatment of - Chronic hepatitis B virus infection in adults HIV-infected adults in combination with other antiretroviral agents

The recommended dose of Tenofovir in chronic hepatitis B virus infection in adults 18 years of age and older with adequate renal function is 300 mg once daily with or without food. Dose Adjustment in renal impairment: Tenofovir is eliminated by renal excretion, so the exposure to tenofovir increases in patients with renal dysfunction. Dosing interval should be adjusted in all patients with creatinine clearance Dosing interval adjustment of Tenofovir in patients with renal impairment Creatinine clearance(mL/min) >= 50 = 50 30 to 49 10 to 29 Haemodialysis Patients Recommended dose and dosing interval 300 mg every 24 hours 300 mg every 48 hours 300 mg every 72 to 96 hours Every 7 days or after a total of approximately 12 hours of dialysis Dose Adjustment in hepatic impairment: No dose adjustment is required in patients with hepatic impairment.

The most common side effects are nausea, vomiting, diarrhea and flatulence.

Coadministration with other drugs: Tenofovir should not be administered concurrently with Emtricitabine and Tenofovir combination or Adefovir Dipivoxil. Lactic Acidosis/Severe Hepatomegaly with Steatosis: Though the risk of occurrence of lactic acidosis is low for Tenofovir, treatment should be suspended in any patient who develops lactic acidosis or hepatotoxicity. Exacerbation of Hepatitis after Discontinuation of Treatment: Discontinuation of Tenofovir therapy may be associated with severe acute exacerbations of hepatitis.

Tenofovir is contraindicated in patients with previously demonstrated hypersensitivity to Tenofovir or any component of the product.

In pregnancy: No clinical data are available for pregnant women being treated with Tenofovir. It should be used during pregnancy only if clearly needed. In lactation: It is not known whether it is excreted in human milk. Mothers should be instructed not to breast feed if they are taking Tenofovir. Drug Interaction Coadministration of Tenofovir with antiretroviral, entecavir, lamivudine, methadone, oral contraceptives, ribavirin and tacrolimus did not result in significant drug interactions. The effects of coadministration of Tenofovir with other drugs that are renally eliminated or are known to affect renal function have not been evaluated.

There is no experience of Tenofovir overdosage reported in patients.

Xynovir tablet: Each box contains 1 blister strip of 12 tablets. Others Pediatric Use Safety and effectiveness of Tenofovir in pediatric patients below the age of 18 years have not been established. Geriatric Use: Clinical studies of Tenofovir did not include sufficient numbers of elderly patients aged 65 years and over to determine whether they respond differently from younger subjects. But care should be taken in dose selection.