Buy Efavirenz (EFV) Cas 154598-52-4

Buy Efavirenz (EFV) Cas 154598-52-4

Efavirenz (EFV), sold under the brand names Sustiva among others, is an antiretroviral medication used to treat and prevent HIV/AIDS.^[1] It is generally recommended for use with other antiretrovirals.^[1] It may be used for prevention after a needlestick injury or other potential exposure.^[1] It is sold both by itself and in combination as efavirenz/emtricitabine/tenofovir.^[1] It is taken by mouth.^[1]

Common side effects include rash, nausea, headache, feeling tired, and trouble sleeping.^[1] Some of the rashes may be serious such as Stevens–Johnson syndrome.^[1] Other serious side effects include depression, thoughts of suicide, liver problems, and seizures.^[1] It is not safe for use during pregnancy.^[1] It is a non-nucleoside reverse transcriptase inhibitor (NNRTI) and works by blocking the function of reverse transcriptase.^[1]

Efavirenz was approved for medical use in the United States in 1998,^[1] and in the European Union in 1999.^[4] It is on the World Health Organization’s List of Essential Medicines.^[6] As of 2016, it is available as a generic medication.^[7][8]

For HIV infection that has not previously been treated, the United States Department of Health and Human Services Panel on Antiretroviral Guidelines recommends the use of efavirenz in combination with tenofovir/emtricitabine (Truvada) as one of the preferred NNRTI-based regimens in adults and adolescents^[9] and children.^[10]

Efavirenz is also used in combination with other antiretroviral agents as part of an expanded post-exposure prophylaxis regimen to reduce the risk of HIV infection in people exposed to a significant risk (e.g. needlestick injuries, certain types of unprotected sex, etc.).^[11][12]

Efavirenz is safe to use during the first trimester of pregnancy.^[13] Efavirenz passes into breast milk and breast-fed infants may be exposed to efavirenz.^[14]

People who have taken this medication before and experienced an allergic reaction should avoid taking further efavirenz dosages. Hypersensitivity reactions include Stevens–Johnson syndrome, toxic skin eruptions, and erythema multiforme.^[3]

Neuropsychiatric effects are the most common adverse effects, and include disturbed sleep (including nightmares, insomnia, disrupted sleep, and daytime fatigue), dizziness, headaches, vertigo, blurred vision, anxiety, and cognitive impairment (including fatigue, confusion, and memory and concentration problems), and depression, including suicidal thinking.^[15][16] Some people experience euphoria.^[15]

Rash and nausea may occur.^[3]

Use of efavirenz can produce a false positive result in some urine tests for marijuana.^[17][18]

Efavirenz may lengthen the QT interval so should not be used in people with or at risk of torsades de pointes.^[19]

Efavirenz may cause convulsions in adult and pediatric populations who have a history of seizures.^[3]

Efavirenz is broken down in the liver by enzymes that belong to the cytochrome P450 system, which include both CYP2B6 and CYP3A4.^[3] Efavirenz is a substrate of these enzymes and can decrease the metabolism of other drugs that require the same enzymes.^[3] However, efavirenz also induces these enzymes, which means the enzyme activity is enhanced and the metabolism of other drugs broken down by CYP2B6 and CYP3A4 can be increased.^[3] People who are taking both efavirenz and other drugs metabolized by the same enzymes might need the dose of their drugs to be increased or decreased.

One group of drugs that efavirenz affects is protease inhibitors, which are used for HIV/AIDS. Efavirenz will lower the blood levels of most protease inhibitors, including amprenavir, atazanavir, and indinavir.^[3] At lowered levels, protease inhibitors may not be effective in people taking both drugs, which means the virus that causes HIV/AIDS won’t be stopped from replicating and may become resistant to the protease inhibitor.

Efavirenz also affects antifungal drugs, which are used for fungal infections such as urinary tract infections. Similar to the effect seen with protease inhibitors, efavirenz lowers the blood levels of antifungal drugs like voriconazole, itraconazole, ketoconazole, and posaconazole.^[3] As a result of lowered levels, antifungal drugs may not be effective in people taking both drugs, which means that the fungi that cause the infection may become resistant to the antifungal.

Efavirenz has also been reported to interact with tubulin and inhibit its polymerization.^[20]

Efavirenz falls in the NNRTI class of antiretrovirals. Both nucleoside and non-nucleoside RTIs inhibit the same target, the reverse transcriptase enzyme, an essential viral enzyme which transcribes viral RNA into DNA. Unlike nucleoside RTIs, which bind at the enzyme’s active site, NNRTIs act allosterically by binding to a distinct site away from the active site known as the NNRTI pocket.

Efavirenz is not effective against HIV-2, as the pocket of the HIV-2 reverse transcriptase has a different structure, which confers intrinsic resistance to the NNRTI class.^[21]

As most NNRTIs bind within the same pocket, viral strains which are resistant to efavirenz are usually also resistant to the other NNRTIs, nevirapine and delavirdine. The most common mutation observed after efavirenz treatment is K103N, which is also observed with other NNRTIs.^[3] Nucleoside reverse-transcriptase inhibitors (NRTIs) and efavirenz have different binding targets, so cross-resistance is unlikely; the same is true with regard to efavirenz and protease inhibitors.^[1