Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three non-nucleoside reverse transcriptase inhibitors (NNRTIs) are currently available for treatment of HIV-1 as part of combination antiretroviral therapy. Oral dosing is administered three times daily for delavirdine (DLV), twice daily for nevirapine (NVP), and once daily for efavirenz (EFV). Rash is a common side effect of all three NNRTIs, and early CNS side effects are also frequent with EFV. Hepatotoxicity is relatively uncommon but requires appropriate monitoring. Drug interactions mediated by the cytochrome P450 system are an important consideration when the NNRTIs are administered concomitantly with other drugs, including protease inhibitors (PIs). HIV strains with reduced susceptibility to NNRTIs can occur with a single mutation in the reverse transcriptase (RT) gene. The available NNRTIs exhibit overlapping genotypic resistance patterns, but newer agents may overcome this problem. NNRTIs have been studied in combination with nucleoside RT inhibitors for first-line HIV therapy, where they have shown at least equivalent antiviral efficacy compared with PI-based regimens over 1-2 years of therapy. NVP and EFV have also been studied as a replacement for a PI within a virologically successful regimen, with the aim of preventing or reducing PI toxicities and simplifying the dosing regimen. Such 'switch' strategies are successful for certain patients in maintaining virologic suppression for 6 months or more and result in varying degrees of improvement in PI-associated toxicities. NNRTIs may offer a benefit when included in salvage regimens for patients failing PI-based therapy, particularly in patients who have not previously been treated with NNRTIs. NVP has been shown to have a substantial favourable impact on the rate of vertical HIV-1 transmission with a simple, cost-effective regimen.
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PMID:Clinical uses of non-nucleoside reverse transcriptase inhibitors. 1089 70

Nevirapine (Viramune, Boehringer Ingelheim) is a non-nucleoside reverse transcriptase (RT) inhibitor (NNRTI) effective in the treatment of HIV-1 infected antiretroviral-naive and -experienced patients. Some recent studies have suggested that nevirapine-based regimens may have an efficacy similar to protease inhibitor (PI)-based regimens, at least in naive patients with CD4+ > 200 microl, while it lacks the drawbacks inherent in PI-containing regimens, such as lipodystrophy and metabolic alterations. Switching from a PI-containing regimen to a nevirapine-containing regimen seems to retain the virological response to therapy and it may also limit or reverse the development of some metabolic disorders induced by PIs. Nevirapine is also effective in preventing mother-to-child transmission of HIV-1 disease and in the treatment of HIV-1 infected children. Nevirapine is well-tolerated, rash being the most common severe adverse effect observed. Hepatotoxicity may also appear with nevirapine, mainly in patients with chronic hepatitis C and/or altered liver function tests. This side effect may occasionally be life-threatening but it can be safely managed in most patients.
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PMID:The role of nevirapine in the treatment of HIV-1 disease. 1182 35

Hepatotoxicity is an adverse effect of all available classes of antiretrovirals, including nucleoside reverse transcriptase inhibitors (NRTI). A syndrome of hepatic steatosis and lactic acidosis has been recognized as a rare, potentially fatal complication since the advent of NRTI monotherapy in the early 1990s. Today, NRTI remain the backbone of antiretroviral combination regimens, and, with the success of current treatment strategies, exposure to two or more of these agents may occur over a number of years. Hepatic steatosis and lactic acidosis are accordingly being observed more frequently, along with a more recently recognized syndrome of chronic hyperlactatemia. These as well as other adverse effects of NRTI are mediated by inhibition of human DNA polymerase gamma, resulting in mitochondrial dysfunction in the liver and other tissues. Early recognition and intervention are essential to avert serious outcomes.
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PMID:Hepatotoxicity of nucleoside reverse transcriptase inhibitors. 1280 69

Implementation of combination antiretroviral therapies has transformed the prognosis of HIV infection during the past decade. Because of its low-pill burden, convenient administration once or twice daily without food restrictions and, in the case of nevirapine, favorable metabolic profile and proven safety in pregnant women and newborns, nonnucleoside reverse transcriptase inhibitors have been shown to be often superior to protease inhibitors as third agents in combination with a backbone of two nucleoside reverse transcriptase inhibitors. Therefore, two nucleoside reverse transcriptase inhibitors plus one nonnucleoside reverse transcriptase inhibitor are currently the most popular used first-line therapies. Hepatotoxicity during the first weeks of therapy with nevirapine, particularly when initiated in women with CD4 counts > 250 cells/mm3, has prompted changes in guidelines and led to a modification in the product label. Recent data, however, suggest that virologically suppressed patients under any other antiretroviral drug combination may safely switch to nevirapine as a part of a simplification strategy, regardless of their current CD4 count. This subset of patients does not show an increased risk of hepatotoxicity or rash with elevated CD4 counts, as has been reported in drug-naive HIV persons. This information is important and may expand the number of candidates who could benefit from nevirapine use, since a substantial proportion of HIV patients show metabolic abnormalities (dyslipidemia, insulin resistance, liver steatosis) and are at increased cardiovascular risk. Fortunately, many of these conditions may ameliorate or improve using nevirapine.
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PMID:Risk for immune-mediated liver reactions by nevirapine revisited. 1861 21

Nevirapine (NVP) is a non-nucleoside reverse transcriptase inhibitor frequently used in combination with other antiretroviral agents for highly active antiretroviral therapy (HAART) of patients infected with the human immunodeficiency virus type 1 (HIV-1). However NVP can cause serious, life-threatening complications. Hepatotoxicity is one of the most severe adverse effects, particularly in HIV patients with chronic hepatitis C virus co-infection as these patients can develop liver toxicity after a relatively short course of treatment. However, the mechanism of NVP-associated hepatotoxicity remains unclear. This study sought to investigate the effect of NVP on protein expression in liver cells using a proteomic approach. HepG2 cells were treated or not treated with NVP and proteins were subsequently resolved by two-dimensional gel electrophoresis. A total of 33 differentially regulated proteins were identified, of which nearly 40% (13/33) were mitochondrial proteins. While no obvious differences were observed between NVP treated and untreated cells after staining mitochondria with mitotracker, RT-PCR expression analysis of three mitochondrially encoded genes showed all were significantly up-regulated in NVP treated cells. Mitochondrial dysfunction was observed in response to treatment even with slightly sub-optimal therapeutic treatment concentrations of NVP. This study shows that NVP induces mitochondrial dysregulation in HepG2 cells.
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PMID:Nevirapine induced mitochondrial dysfunction in HepG2 cells. 2883 69