Purine analogue

Purine analogues are antimetabolites which mimic the structure of metabolic purines.

Azathioprine is the main immunosuppressive cytotoxic substance. It is widely used in transplantations to control rejection reactions. It is nonenzymatically cleaved to 6-mercaptopurine that acts as a purine analogue and an inhibitor of DNA synthesis. By preventing the clonal expansion of lymphocytes in the induction phase of the immune response, it affects both the cell and the humoral immunity. It also successfully suppresses autoimmunity.
Mercaptopurine
Thioguanine is used to treat acute leukemias and remissions in acute granulocytic leukemias
Fludarabine inhibits function of multiple DNA polymerases, DNA primase, DNA ligase I and is S phase-specific (since these enzymes are highly active during DNA replication).
Pentostatin and cladribine are adenosine analogs which are primarily used to treat hairy cell leukemia.

DNA-synthesis
inhibitor

TK activated

Purine analogue	guanine (Aciclovir^#/Valacyclovir, Ganciclovir/Valganciclovir, Penciclovir/Famciclovir) adenine (Vidarabine)

Pyrimidine analogue	uridine (Idoxuridine, Trifluridine, Edoxudine) thymine (Brivudine) cytosine (Cytarabine)

Not TK activated

Other

assembly: Rifampicin

Nucleotide analogues/NtRTIs: Adefovir • Tenofovir

Multiple/general

Nucleic acid inhibitors	Cidofovir

Interferon	Interferon alfa-2b • Peginterferon alfa-2a

Multiple/unknown	Ribavirin^#/Taribavirin^†

ErbB2/PI3K Pathway	NOV-205^§ • NOV-002^†

virs(prot)/clss

cutn/syst (hppv/hiva, infl/zost/zoon)/epon

drugJ(dnaa, rnaa, rtva, vacc)

Nucleic acid constituents

Ribonucleoside	Adenosine · Guanosine · 5-Methyluridine · Uridine · Cytidine

Deoxyribonucleoside	Deoxyadenosine · Deoxyguanosine · Thymidine · Deoxyuridine · Deoxycytidine

Nucleotide
(Nucleoside monophosphate)

Nucleoside diphosphate

biochemical families: prot · nucl · carb (glpr, alco, glys) · lipd (fata/i, phld, strd, gllp, eico) · amac/i · ncbs/i · ttpy/i