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5 Cards in this Set
- Front
- Back
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Nonnucleoside Reverse Transcriptase Inhibitors (NNRTIs) |
Nonnucleoside Reverse Transcriptase Inhibitors (NNRTIs) NNRTIs bind to a site on reverse transcriptase different from the binding site of NRTIs. Nonnucleoside drugs do not require phosphorylation to be active and do not compete with nucleoside triphosphates. There is no cross-resistance with NRTIs. Resistance from mutations in the pol gene occurs very rapidly if these agents are used as monotherapy. |
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Delavirdine |
Delavirdine—Drug interactions are a major problem with delavirdine, which is metabolized by both CYP3A4 and CYP2D6. Its blood levels are decreased by antacids, ddI, phenytoin, rifampin, and nelfinavir. Conversely, the blood levels of delavirdine are increased by azole antifungals and macrolide antibiotics. Delaviridine increases plasma levels of several benzodiazepines, nifedipine, protease inhibitors, quinidine, and warfarin. Delavirdine causes skin rash in up to 20% of patients, and the drug should be avoided in pregnancy because it is teratogenic in animals. |
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Efavirenz |
Efavirenz—Efavirenz can be given once daily because of its long half-life. Fatty foods may enhance its oral bioavailability. Efavirenz is metabolized by hepatic cytochromes P450 and is frequently involved in drug interactions. Toxicity of efavirenz includes CNS dysfunction, skin rash, and elevations of plasma cholesterol. The drug should be avoided in pregnancy, particularly in the first trimester because fetal abnormalities have been reported in animals at doses similar to those used in humans. |
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Etravirine |
Etravirine—Etravirine, the newest NNRTI approved for treatment-experienced HIV patients, may be effective against HIV strains resistant to other drugs in the group. The drug causes rash, nausea, and diarrhea. Elevations in serum cholesterol, triglycerides, and transaminase levels may occur. Etravirine is a substrate as well as an inducer of CYP3A4 and also inhibits CYP2C9 and CYP2C19 and may be involved in significant drugdrug interactions. |
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Nevirapine |
Nevirapine—Nevirapine has good oral bioavailability, penetrates most tissues including the CNS, has a half-life of more than 24 h and is metabolized by the hepatic CYP3A4 isoform. The drug is used in combination regimens and is effective in preventing HIV vertical transmission when given as single doses to mothers at the onset of labor and to the neonate. Hypersensitivity reactions with nevirapine include a rash, which occurs in 15–20% of patients, especially female. Stevens-Johnson syndrome and a life-threatening toxic epidermal necrolysis have also been reported. Nevirapine blood levels are increased by cimetidine and macrolide antibiotics and decreased by enzyme inducers such as rifampin. |
