What is Tenofovir disoproxil Zentiva and what is it used for?
Tenofovir disoproxil Zentiva is an antiviral medicine used to treat patients 12 years of age or older with human immunodeficiency virus type 1 (HIV-1) infection, a virus that causes acquired immune deficiency syndrome (AIDS) . Tenofovir disoproxil Zentiva is used in combination with other medicines for HIV. In adolescents (aged 12 to 18 years) the medicine is only indicated in patients who cannot receive first-line treatment with other nucleotide reverse transcriptase inhibitors (NRTIs). In the case of patients who have previously taken other medicines to treat HIV infection, doctors should prescribe Tenofovir disoproxil Zentiva only after evaluating the patient's previous antiviral treatments or the probability that the virus responds to antiviral therapies.
Tenofovir disoproxil Zentiva is also used to treat chronic (long-term) hepatitis B virus infections in adults and adolescents 12 years of age or over with liver damage but whose liver still works (compensated liver disease). In adults it can also be used in patients with liver damage whose liver does not work properly (decompensated liver disease) and in patients who do not respond to lamivudine treatment (another hepatitis B drug).
Tenofovir disoproxil Zentiva contains the active substance tenofovir disoproxil. It is a "generic medicine". This means that Tenofovir disoproxil Zentiva is similar to a 'reference medicine' already authorized in the European Union (EU) called Viread. For more information on generic medicines, see the questions and answers by clicking here.
How is Tenofovir disoproxil Zentiva used?
Tenofovir disoproxil Zentiva can only be obtained with a prescription and treatment should be started by a doctor who has experience in the treatment of HIV infection or chronic hepatitis B.
Tenofovir disoproxil Zentiva is available as tablets (245 mg) taken once daily orally with food. The dose may need to be decreased or the medicine given less frequently in patients with moderately or severely reduced kidney function. For more information on how to take the medicine, including the dosage for adults and adolescents, see the summary of product characteristics (also part of the EPAR).
How does Tenofovir disoproxil Zentiva work?
The active ingredient in Tenofovir disoproxil Zentiva, tenofovir disoproxil, is a "prodrug" that is converted into tenofovir in the body.
Tenofovir is a nucleotide reverse transcriptase inhibitor (NRTI). In HIV infection, it blocks the action of reverse transcriptase, an enzyme produced by HIV that allows it to infect cells and reproduce. Tenofovir disoproxil Zentiva, taken in combination with other antiviral medicines, reduces the amount of HIV in the blood and keeps it at a low level. Tenofovir disoproxil Zentiva does not cure HIV infection or AIDS, but it may delay the damage to the immune system and the development of infections and diseases associated with AIDS.
Tenofovir also interferes with the action of an enzyme produced by the type B hepatitis virus called "DNA polymerase", which contributes to the formation of viral DNA. Tenofovir disoproxil Zentiva stops the production of DNA by the virus, thus preventing it from multiplying and spreading.
What benefit has Tenofovir disoproxil Zentiva shown during the studies?
Because Tenofovir disoproxil Zentiva is a generic medicine, studies in patients have been limited to tests to determine its bioequivalence to the reference medicine, Viread. Two medicines are bioequivalent when they produce the same levels of active ingredient in the body.
Because Tenofovir disoproxil Zentiva is a generic medicine and is bioequivalent to the reference medicine, its benefits and risks are considered to be the same as those of the reference medicine.
What are the risks associated with Tenofovir disoproxil Zentiva?
Because Tenofovir disoproxil Zentiva is a generic medicine and is bioequivalent to the reference medicine, its benefits and risks are considered to be the same as those of the reference medicine.
Why has Tenofovir disoproxil Zentiva been approved?
The Agency's Committee for Medicinal Products for Human Use (CHMP) concluded that, in accordance with EU requirements, Tenofovir disoproxil Zentiva has been shown to have comparable quality and to be bioequivalent to Viread. Therefore, the CHMP considered that, as in the case of Viread, the benefits outweigh the identified risks and recommended to approve the use of Tenofovir disoproxil Zentiva in the EU.
What measures are being taken to ensure the safe and effective use of Tenofovir disoproxil Zentiva?
The company that markets Tenofovir disoproxil Zentiva will ensure that all physicians who should prescribe or administer the medicine receive illustrative material containing important safety information, especially on the risks and precautions to be taken regarding renal function and bone tissue.
Recommendations and precautions to be followed by healthcare professionals and patients for Tenofovir disoproxil Zentiva to be used safely and effectively have also been included in the summary of product characteristics and the package leaflet.
More information on Tenofovir disoproxil Zentiva
For the full EPAR of Tenofovir disoproxil Zentiva see the Agency's website: ema.europa.eu/Find medicine / Human medicines / European public assessment reports. For more information about treatment with Tenofovir disoproxil Zentiva, read the package leaflet (also part of the EPAR) or contact your doctor or pharmacist.
The full EPAR for the reference medicine can also be found on the Agency's website.
