This class of compounds is a common treatment for viral
diseases, most notably HIV
is the most well known of the nucleoside analog
s (NAs), but they all have fairly similar overall structure. They follow the basic nucleoside moiety
, but are always 2',3'-dideoxy or didehydroxy
, to prevent them from being incorporated into an elongating DNA
chain. Instead, they occupy the active site of reverse transcriptase
and prevent it from functioning. In general, this class of compounds is toxic
to the bone marrow
, requiring that they only be used when the disease is severe enough. Some examples of nucleoside analogs other than AZT include 2',3'-didehydro-3'-deoxythymidine (d4T) and 2',3'-dideoxyinosine (ddI), both of which seem to cause less marrow toxicity than AZT.
The antivirals which are used for the treatment of herpes
) are also nucleoside analogs (acyclovir
), but are considerably different in structure from the HIV drugs.