Product Information
Registration Status: ActiveSIN15322P
DESCOVY FILM COATED TABLET 200MG/25MG is approved to be sold in Singapore with effective from 2017-08-21. It is marketed by GILEAD SCIENCES SINGAPORE PTE LTD, with the registration number of SIN15322P.
This product contains Emtricitabine 200mg, and Tenofovir Alafenamide 10mg in the form of TABLET, FILM-COATED. It is approved for ORAL use.
This product is manufactured by Patheon Inc. in CANADA,Gilead Sciences Ireland UC (Primary and secondary packager) in IRELAND, andRottendorf Pharma GmbH (Ostenfelder) in GERMANY.
It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.
Product Reference
Important Note: For generic product, the SPC/PIL provided may not be brand specific.
{{/items}} {{^items}}Description
Emtricitabine is a nucleoside reverse transcriptase inhibitor (NRTI) for the treatment of HIV infection in adults. Emtricitabine is an analogue of cytidine. The drug works by inhibiting reverse transcriptase, the enzyme that copies HIV RNA into new viral DNA.
Indication
Indicated, in combination with other antiretroviral agents, for the treatment of HIV-1 infection in adults and for postexposure prophylaxis of HIV infection in health care workers and others exposed occupationally or nonoccupationally via percutaneous injury or mucous membrane or nonintact skin contact with blood, tissues, or other body fluids associated with risk for transmission of the virus.
Mechanism of Action
Emtricitabine works by inhibiting reverse transcriptase, the enzyme that copies HIV RNA into new viral DNA. Emtricitabine is a synthetic nucleoside analogue of cytidine. It is phosphorylated by cellular enzymes to form emtricitabine 5'-triphosphate, which is responsible for the inhibition of HIV-1 reverse transcriptase. It competes with the natural substrate deoxycytidine 5'-triphosphate and incorporates into nascent viral DNA, resulting in early chain termination. Therefore emtricitabine inhibits the activity of HIV-1 reverse transcriptase (RT) both by competing with the natural substrate deoxycytidine 5'-triphosphate and by its incorporation into viral DNA. By inhibiting HIV-1 reverse transcriptase, emtricitabine can help to lower the amount of HIV, or "viral load", in a patient's body and can indirectly increase the number of immune system cells (called T cells or CD4+ T-cells). Both of these changes are associated with healthier immune systems and decreased likelihood of serious illness.
Pharmacokinetics
- Absorption
- Rapidly absorbed (mean absolute bioavailability of 93% for capsules, and 75% for solution). Food does not effect absorption.
- Distribution
- Metabolism
- Minimally transformed (13%), most appears unchanged in urine (86%). The biotransformation of emtricitabine includes oxidation of the thiol moiety to form the 3′-sulfoxide diastereomers (~ 9% of dose) and conjugation with glucuronic acid to form 2′-O-glucuronide (~ 4% of dose). In vitro studies indicate emtricitabine is not an inhibitor or cytochrome P450 enzymes.
- Elimination
Clearance
* 302 +/- 94 mL/min [Renal Function Creatinine Clearance>80 ml/min] * 168 +/- 10 mL/min [Renal Function Creatinine Clearance 50-80 ml/min] * 138 +/- 28 mL/min [Renal Function Creatinine Clearance 30-49 ml/min] * 99 +/- 6 mL/min [Renal Function Creatinine Clearance
Toxicity
Symptoms of overdose include serious liver problems (hepatotoxicity, with liver enlargement and fat in the liver called steatosis) or a lactic acidosis (buildup of an acid in the blood).
Active Ingredient/Synonyms
(−)-(2R,5S)-5-fluoro-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine | (−)-2'-deoxy-5-fluoro-3'-thiacytidine | (−)-cis-4-amino-5-fluoro-1-(2-hydroxymethyl-1,3-oxathiolan-5-yl)-(1H)-pyrimidin-2-one | (−)-FTC | (−)-β-2',3'-dideoxy-5-fluoro-3'-thiacytidine | (2R-cis)-4-amino-5-fluoro-1-(2-(hydroxymethyl)-1,3-oxathiolan-5-yl)-2(1H)-pyrimidinone | 4-amino-5-fluoro-1-((2R,5S)-2-(hydroxymethyl)-1,3-oxathiolan-5-yl)pyrimidin-2(1H)-one | 4-Amino-5-fluoro-1-((2R,5S)-2-hydroxymethyl-[1,3]oxathiolan-5-yl)-1H-pyrimidin-2-one | 5-fluoro-1-((2R,5S)-2-(hydroxymethyl)-1,3-oxathiolan-5-yl)cytosine | Emtricitabin | Emtricitabina | Emtricitabine | Emtricitabinum | Emtricitabine |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.
Description
Tenofovir alafenamide fumarate (TAF) is a nucleotide reverse transcriptase inhibitor (NRTI) and a novel ester prodrug of the antiretroviral tenofovir. Following oral administration, TAF is converted in vivo to tenofovir, an acyclic nucleoside phosphonate (nucleotide) analog of adenosine 5′-monophosphate. Tenofovir mimics normal DNA building blocks but is lacking a 3'-OH molecule required for phosphodiester bond linkage. By competing with regular nucleotides for incorporation into proviral DNA and prevention of the formation of the 5' to 3' phosphodiester linkage required for DNA elongation, tenofovir causes early chain termination and prevents proviral DNA transcription. Although tenofovir (available as tenofovir disoproxil fumarate) has a good safety profile and efficacy, and is currently a cornerstone of HIV antiviral treatment, its use has been associated with nephrotoxicity and reduced bone mineral density. In comparison, TAF has been shown to have improved antiviral efficacy, enhanced delivery of TFV into peripheral blood mononuclear cells (PBMCs) and lymphatic tissues, a higher barrier to resistance, and an improved safety profile. Improved renal safety is likely attributable to lower circulating plasma concentrations of tenofovir and therefore less exposure and damage to bone and the kidneys, where tenofovir is metabolized. Because HIV antiretroviral therapy is usually life-long, reduced toxicity and improved efficacy results in better patient outcomes and improved adherence in the long term. Tenofovir alafenamide fumarate is currently available in two fixed dose combination products: Odefsey (emtricitabine, rilpivirine, and tenofovir alafenamide), and Descovy (emtricitabine and tenofovir alafenamide). Both products are indicated for the treatment of HIV-1 infection in adults and pediatric patients 12 years of age and older.
Indication
For use in the treatment of HIV infection and chronic hepatitis B.
Mechanism of Action
Tenofovir alafenamide fumarate (TAF) is a nucleotide reverse transcriptase inhibitor (NRTI) and a novel ester prodrug of the antiretroviral tenofovir. Following oral administration, TAF is converted in vivo to tenofovir, an acyclic nucleoside phosphonate (nucleotide) analog of adenosine 5′-monophosphate. Tenofovir mimics normal DNA building blocks but is lacking a 3'-OH molecule required for phosphodiester bond linkage. By competing with regular nucleotides for incorporation into proviral DNA and prevention of the formation of the 5' to 3' phosphodiester linkage required for DNA elongation, tenofovir causes early chain termination and prevents proviral DNA transcription.
Pharmacokinetics
- Absorption
- Tmax is observed at 1 hour post oral administration.
- Distribution
- Metabolism
- In vivo, TAF is hydrolyzed within cells to form tenofovir (major metabolite), which is phosphorylated to the active metabolite, tenofovir diphosphate. In vitro studies have shown that TAF is metabolized to tenofovir by cathepsin A (also known as Lysosomal Protective Protein) in peripheral blood mononuclear cells (PBMCs) and macrophages; and by Carboxylesterase 1 (CES1) in hepatocytes.
- Elimination
Active Ingredient/Synonyms
Tenofovir alafenamide | Tenofovir alafenamide |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.