Tenofovir/emtricitabine

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Tenofovir/emtricitabine
Combination of
Tenofovir disoproxil fumarate Nucleotide analogue reverse transcriptase inhibitor
Emtricitabine Nucleoside reverse transcriptase inhibitor
Clinical data
Pregnancy cat. B (US)
Legal status POM (UK) -only (US)
Routes Oral
Identifiers
ATC code J05AR03
PubChem CID 11954236
NIAID ChemDB 214126
 YesY (what is this?)  (verify)

Tenofovir/emtricitabine, trademark Truvada by Gilead Sciences, is a fixed-dose combination of two antiretroviral drugs used for the treatment of HIV. It consists of 300 milligrams of tenofovir disoproxil fumarate (of which 245 mg tenofovir) and 200 milligrams of emtricitabine.

The drug has been approved for pre-exposure prophylaxis against HIV infection. A Cochrane review found that both tenofovir alone, as well as the tenofovir/emtricitabine combination, decreased the risk of contracting HIV by 51% (RR 0.51; 95% CI 0.30 to 0.86; 8918 participants). [1] The Food and Drug Administration approved it for prophylactic use on July 16, 2012.[2]In studies, tenofovir reduced the incidence of HIV infection, especially in high-risk individuals, (by 42% in MSM in the iPrEX study) but produced conflicting results in other studies (notably the FEM-PrEP study in heterosexual African women).[3]One study estimated through mathematical modeling that daily intake of Truvada could potentially achieve a 99% of risk reduction of contracting HIV in high risk individuals, though this level of protection has never been demonstrated in clinical trials.[4]

In certain studies, the drug has demonstrated rare side effects including: transient nausea, dizziness, loss of appetite and loose stools.[5]

Clinical studies[edit]

Truvada pills

The HEAT study (randomized, double-blind, placebo-matched, multicentre) showed that once-daily emtricitabine/tenofovir plus lopinavir/ritonavir or boosted atazanavir or efavirenz were effective in the initial treatment of patients with HIV-1 infection (with screening plasma HIV-1 RNA levels of ≥1,000,000 copies/mL in ACTG 5202).[6]

In other randomized trials, emtricitabine/tenofovir DF 200 mg/300 mg once daily was an effective backbone for boosted protease inhibitor (PI)-based regimens in the initial treatment of HIV-1 infection.[6][7]

Emtricitabine/tenofovir DF in combination with various boosted PIs was generally well tolerated by adults with HIV-1 infection.[6]

Truvada was developed by Gilead Sciences and approved by the United States Food and Drug Administration in 2004.

A combination pill containing Truvada and efavirenz (Sustiva) is also available and is marketed as Atripla.

Contraindications[edit]

Truvada should not be taken by patients with an unknown or a positive HIV-1 form of the disease for pre-exposure prophylaxis. Patients who are infected with HIV should use Truvada only in combination with other antiretroviral medications.[8]

Drug Interactions[edit]

The tenofovir component of Truvada interacts with the following drugs: didanosine, atazanavir, and lopinavir/ritonavir.

When tenofovir is coadministered with didanosine, the concentration of didanosine increases, and may lead to didanosine toxicity which may result in complications such as pancreatitis and neuropathy. If authorised, the dose of didanosine may be reduced or discontinued completely.

The coadministration of tenofovir and atazanavir results in decreased concentrations of atazanavir and increased concentrations of tenofovir. Atazanavir may be taken with Truvada only with ritonavir and must be monitored for tenofovir toxicity.

The coadministration of tenofovir and lopinavir/ritonavir increases the concentration of tenofovir and must be monitored for tenofovir toxicity.[9]

References[edit]

  1. ^ Okwundu CI, Uthman OA, Okoromah CAN (2012). "Antiretroviral pre-exposure prophylaxis (PrEP) for preventing HIV in high-risk individuals". In Okwundu, Charles I. Cochrane Database Syst Rev 7 (7): CD007189. doi:10.1002/14651858.CD007189.pub3. PMID 22786505. 
  2. ^ "FDA approves first pill to help prevent HIV". Seattle Times. 16 July 2012. 
  3. ^ "PK Modeling of Daily TDF/FTC (Truvada) Provides Close to 100% Protection Against HIV Infection". April 2012. 
  4. ^ "PK Modeling of Daily TDF/FTC (Truvada) Provides Close to 100% Protection Against HIV Infection". April 2012. 
  5. ^ MedicineNet.com. http://www.medicinenet.com/emtricitabine-tenofovir-oral/article.htm
  6. ^ a b c Perry CM (2009). "Emtricitabine/tenofovir disoproxil fumarate: in combination with a protease inhibitor in HIV-1 infection". Drugs 69 (7): 843–57. doi:10.2165/00003495-200969070-00005. PMID 19441871. 
  7. ^ Cohen J (December 2010). "HIV/AIDS clinical trials. A powerful and perplexing new HIV prevention tool". Science 330 (6009): 1298–9. doi:10.1126/science.330.6009.1298. PMID 21127220. 
  8. ^ Truvada 2012, p. 1.
  9. ^ Truvada 2012, p. 2.
  • Truvada [package insert]. Foster City, CA: Gilead Sciences, Inc.; 2012.

External links[edit]