Anti-HIV: NNRTI

Question 1

Nevirapine

Answer 1

• mechanism: highly selective noncompetitive nonnucleoside inhibitor of HIV reverse transcriptase
• kinetics: oral (well absorbed); inducer of cytochrome P450 => increase metabolism of drugs; lipophilic (widely distributed, including mother’s milk)
• clinical: prophylaxis during labor; should not be initiated in women with CD4 T cell count greater than 250 cells/mm^3 and in men greater than 400 cell/mm^3
• toxicity/interactions: rashes (cases of Steven-Johnson)

Question 2

Delavirdine

Answer 2

• mechanism: highly selective noncompetitive nonnucleoside inhibitor of HIV reverse transcriptase
• kinetics: oral (rapidly absorbed); extensively metabolized and excreted; inhibits cytochrome P450 affecting other drug metabolism
• clinical: HIV
• toxicity/interactions: rash (some cases of Stevens-Johnson)

Question 3

Efavirenz

Answer 3

• mechanism: highly selective noncompetitive nonnucleoside inhibitor of HIV reverse transcriptase
• kinetics: oral (with high-fat meal better absorbed); inducer of cytochrome P450
• clinical: HIV
• toxicity/interactions: potential severe hepatotoxicity; involves CNS (vivid dreams)
• misc: avoid in pregnancy; increase metabolism of other drugs (including protease inhibitors, etc)