Indications

This is indicated for the treatment of:

Chronic hepatitis B virus infection in adults

HIV infected adults in combination with other anti retroviral agents

Therapeutic Class

Drugs for HIV / Anti-retroviral drugs, Hepatic viral infections (Hepatitis B)

Pharmacology

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

Dosage & Administration

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.

Interaction

Co-administration of Tenofovir with anti-retroviral, entecavir, lamivudine, methadone, oral contraceptives, ribavirin and tacrolimus did not result in significant drug interactions. The effects of co-administration of Tenofovir with other drugs that are renally eliminated or are known to affect renal function have not been evaluated.

Contraindications

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

Side Effects

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

Pregnancy & Lactation

Pregnancy: Pregnancy category B. It should be used during pregnancy only if clearly needed.

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.

Precautions & Warnings

Co-administration with other drugs: Tenofovir should not be administered concurrently with Emtricitabine & 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 exacerbation of hepatitis.

Use in Special Populations

Pediatric use: Safety and effectiveness of Tenofovir in pediatric patients below the age of 18 years have not been established.

Geriatrics use: Clinical studies of Tenofovir did not include sufficient numbers of subjects aged 65 years and over to determine whether they respond differently from younger subjects. But care should be taken in dose selection, and it may be useful to monitor renal function.

Renal Impairment: Haemodialysis patients: 300 mg once every 7 days or after a cumulative total of 12 hr of dialysis.

CrCl (10-29 mL/min): 300 mg 72-96 hrly.

CrCl (30-49 mL/min): 300 mg 48 hrly.

Hepatic impairment: No dose adjustment is required in patients with hepatic impairment.

Overdose Effects

There is no experience of Tenofovir overdose reported in patients

Storage Conditions

Store in a cool and dry place, protected from light and moisture. Keep the medicine out of the reach of children.