Snapshot A 31-year-old woman is in the labor and delivery unit undergoing about to undergo a cesarean section at 38-weeks gestation. She is HIV-positive and was found to have an HIV RNA viral load of 1200 copies/mL. She has been nonadherent to her medications. She is started on intravenous zidovudine 3 hours prior to the surgery in order to decrease the risk of HIV transmission to the newborn. Introduction Mechanism of action nucleoside reverse transcriptase inhibitors (NRTIs) NRTIs are phosphorylated inside the infected cell, inhibiting the viral reverse transcriptase and impairing viral replication terminates chain elongation the NRTIs lacks a 3′ OH group note that these are highly active against HIV-1 and HIV-2 tenofovir is a nucleotide reverse transcriptase inhibitor, the others are nucleosides non-nucleoside reverse transcriptase inhibitors (NNRTIs) a similar mechanism of action as NRTIs; however, it binds to the viral reverse transcriptase at a different site note these are highly active against HIV-1 but not HIV-2 NNRTIs do not require phosphorylation Mechanism of resistance resistance mutations (there are multiple) Clinical use a component of antiretroviral therapy for treating HIV Adverse reactions NRTIs mitochondrial toxicity can result in peripheral neuropathy, pancreatitis, lipoatrophy, and/or hepatic steatosis lactic acidosis bone marrow suppressing NNRTIs there are no specific class-related adverse events neurologic and psychiatric side effects (efavirenz and rilpivirine) NRTIs (Reverse Transcriptase Inhibitors) Abacavir (ABC) Contraindicated in patients with HLA-B*5701 associated with increased risk of hypersensitivity Didanosine (ddl) Associated with pancreatitis Emtricitabine (FTC) - Lamivudine (3TC) - Stavudine (d4T) - Tenofovir (TDF) - Zidovudine (ZDV) Associated with anemia Can be used for post-exposure prophylaxis intrapartum prophylaxis NNRTIs (Reverse Transcriptase Inhibitors) Delavirdine Contraindicated in pregnancy Efavirenz Associated with vivid dreams and central nervous system symptoms Contraindicated in pregnancy Nevirapine -