Comprehensive Nursing Pharmacology Q 181
Which choice describes the action of nucleoside analogs?
A. Exert anti-HIV activity at the reverse transcriptase level and cause premature termination of viral DNA chain synthesis.
B. Completely stop the replication of HIV virus.
C. Allow for a patient to become non-contagious after taking for at least 3 days.
D. Are all equally effective and free of side effects.
Correct Answer: A. Exert anti-HIV activity at the reverse transcriptase level and cause premature termination of viral DNA chain synthesis
This choice correctly describes the action of nucleoside analogs. The nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) were the first class of antiretroviral drugs to be approved by the FDA. NRTIs are taken as prodrugs and must be taken into the host cell and phosphorylated before they become active. Once inside the host cell, cellular kinases will activate the drug. The drug exerts its effect through its structure.
Option B: NRTIs lack a 3’-hydroxyl group at the 2’-deoxyribosyl moiety and will have either a nucleoside or nucleotide as a base. Due to the missing 3’hydroxyl group, the NRTI prevents the formation of a 3’-5’-phosphodiester bond in growing DNA chains and can thus prevent replication of the virus.
Option C: An interesting feature of these drugs is that their incorporation during RNA-dependent DNA or DNA-dependent DNA synthesis, which inhibits the production of either positive or negative strands of the DNA.
Option D: Currently, research and trials are underway to assess the efficacy in the use of reverse transcriptase inhibitors for pre-exposure prophylaxis. Studies show that there is anywhere from a 67% to 75% reduction in the risk of becoming infected through the use of pre-exposure prophylaxis.