Efavirenz/emtricitabine/tenofovir

Efavirenz/emtricitabine/tenofovir disoproxil
Combination of
Efavirenz non-nucleoside reverse transcriptase inhibitor
Emtricitabine nucleoside analog reverse transcriptase inhibitor
Tenofovir disoproxil nucleotide analog reverse transcriptase inhibitor
Clinical data
Trade names Atripla, Viraday
Pregnancy
category
  • US: D (Evidence of risk)
Routes of
administration		 Oral
Legal status
Legal status
Identifiers
CAS Number 731772-50-2 YesY
ATC code J05AR06 (WHO)
NIAID ChemDB 026223
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Efavirenz/emtricitabine/tenofovir disoproxil, sold under the trade name Atripla among others, is a fixed-dose combination drug for the treatment of HIV infection. It combines tenofovir disoproxil, emtricitabine, and efavirenz into a fixed-dose pill. Combining the three drugs into a single, once-daily pill reduces pill burden and simplifies dosing schedules, and therefore has the potential to increase adherence to antiretroviral therapy.

Atripla is the first multi-class antiretroviral drug available in the United States and represents the first collaboration between two U.S. pharmaceutical companies to combine their patented anti-HIV drugs into one product.[1] The drug retails in the United States for US$1,850 for a one-month supply. An equivalent two pill regimen is available in developing countries at a price of about US$1.00 per day, as Gilead Sciences has licensed the patents covering emtricitabine/tenofovir to the Medicines Patent Pool[2] and Merck and Co makes efavirenz available in developing countries at a reduced price.[3] It was approved by the U.S. FDA on July 12, 2006. In the UK, the drug cost to the NHS is £626.90 per month[4] as of March 2012.

In adults, it is taken once daily on an empty stomach. Dosing at bedtime is recommended to improve tolerability of nervous system symptoms. Atripla is not recommended for patients under 18 years of age.

In North America and Europe, Atripla is marketed jointly by Gilead Sciences and Bristol-Myers Squibb, but in much of the developing world, marketing and distribution is handled by Merck & Co.[5]

History

Atripla was approved as a once daily tablet to treat HIV in 2006. The main advantage of the new drug Atripla was that it could be taken once daily and reduces the overall stress in an antiretroviral regimen.[6] There is currently no generic version of Atripla available in the United States. An equivalent two pill regimen is available in developing countries at a price of about US$1.00 per day, as Gilead Sciences has licensed the patents covering emtricitabine/tenofovir to the Medicines Patent Pool[7] and Merck and Co makes efavirenz available in developing countries at a reduced price.[8]

Dosage

Recommended dosage for Atripla is 1 tablet at or before bedtime. Side effects can be reduced if Atripla is taken on an empty stomach. For patients with renal or hepatic insufficiency, patient can take 1 tablet by mouth once a day. However, patients whose CrCl levels are less than 50ml/min should not follow this dosage. Instead, patients should be prescribed drug components of the fixed-dose combinations while adjusting TDF and FTC doses according to the patient’s CrCl levels.[9]

Mechanism of action

Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) of HIV-1. Emtricitabine is a nucleoside reverse transcriptase inhibitor (NRTI) of HIV-1.Tenofovir is a nucleotide reverse transcriptase inhibitor of HIV-1, and it can be classified as an NtRTI. These three drugs work in combination to target the HIV reverse transcriptase protein in three ways, which reduces the virus’s capacity to mutate.[10]

In combination studies there were synergistic antiviral effects observed between emtricitabine and efavirenz, efavirenz and tenofovir, and emtricitabine and tenofovir.[10]

Side effects

Common side effects of Atripla are tiredness, dizziness, gastrointestinal distress, and skin discoloration. More severe side effects are hallucinations, sleeplessness and depression.[11]

Interactions

Medications that should not be taken with Atripla are Vascor (bepridil), Versed (midazolam), Orap (pimozide), Halcion (triazolam), or ergot derivatives (for example, Wigraine and Cafergot)." Discuss any other HIV or hepatitis medications you are taking with your doctor to avoid complications. Additionally, St. John's wort is known to reduce the effectiveness of Atripla, resulting in increased viral load and possible resistance to Atripla.[12]

Contraindications

Patients who have shown strong hypersensitivity to efavirenz, a constituent of Atripla, should not take Atripla. Drugs that are contraindicated in the intake of Atripla are: voriconazole, ergot derivative drugs, benzodiazepines midazolam and triazolam, calcium channel blocker bepridil, cisapride, pimozide and St. John’s wort (Hypericum perforatum). Breastfeeding is also contraindicated.[10]

Appearance

Atripla is a pink, film-coated tablet with "123" impressed on one side.

References

External links

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