Nucleoside and Nucleotide Analogs

Question 1

Azidothymidine (AZT) and Didanosine (ddI)

Answer 1

Nucleoside analogs that lack a free 3’ hydroxyl (-OH) group. These drugs have high affinity for reverse transcriptase enzyme and inhibit their activity. They are therefore used in the treatment of retro-viral infections such as HIV.

Question 2

Acyclovir

Answer 2

A potent inhibitor of viral DNA polymerase and causes termination of DNA replication. It is used in the treatment of Herpes virus.

Question 3

Tenofovir

Answer 3

Nucleotide analog that possess an open chain structure in place of the pentose sugar ring structure. Tenofovir is a potent reverse transcriptase inhibitor that is used to treat HIV infection.

Question 4

Cytosine arabinoside and adenosine arabinoside

Answer 4

Inhibit the activity of DNA polymerase and inducing DNA damage by incorporation into DNA during replication.
-Used as anti-cancer drugs by selectively destroying the rapidly dividing cancer cells

Question 5

Cytidine Analogs
5-aza-2’-deoxycytidine and 5-azacytidine

Answer 5

Cytidine Analogs that disrupt the epigenetic process of DNA methylation. Direct inhibitors of DNA methyl-transferase enzymes

Question 6

5-Flourouracil

Answer 6

Anti-cancer agent. In cells it is converted to FdUMP which inhibits thymidylate kinase, and also inhibiting synthesis of thymine nucleotides required for DNA synthesis

Question 7

Azathioprine

Answer 7

Metabolized to 6-mercaptopurine which suppresses rejection during organ transplantation

Question 8

Allopurinol

Answer 8

Treatment for gout. It inhibits xanthine oxidase thus lowering the conversion of purine bases to uric acid end products. The purines are excreted as xanthine and hypoxanthine which are more soluble than uric acid.

Question 9

Adenosine (Adenocard)

Answer 9

IV is used to treat supraventricular tachycardia, slows heart rate.