Question

How does AZT prevent viral replication?

Answer 1

Hint: The full form of AZT is azidothymidine, additionally called zidovudine, a medication used to prevent the advancement of (AIDS) in patients contaminated with HIV (human immunodeficiency infection). It is an antiretroviral agent.

Complete answer:
AZT, in full azidothymidine, additionally called zidovudine, is a medication that is utilized in curing and preventing retroviral infections like AIDS. The HIV infection is a RNA infection (or retrovirus) and to enter an infection it needs to utilize a chemical called switch transcriptase.

Mechanism of AZT action:
The AZT primarily works by inhibiting the reverse transcriptase in HIV. The role of reverse transcriptase is it catalyses the reverse transcription of RNA to DNA copies in the virus. This process produces the Double stranded DNA of the virus cell which incorporates into the host or the infected cell. Thus, AZT inhibits the retrovirus effect without affecting the action of DNA polymerase which is used for transcription in the host cell.

Side effects of AZT- It can cause headache, nausea, acid reflux, loss of appetite, discoloration of nails, mood elevations etc. At very high doses, it can cause effects on skeletal and cardiac muscles.

AZT alone cannot inhibit all the HIV replication. It can only slow down the viral replication and disease progression. Long term treatment of AZT can lead to resistance in the virus due to mutation of its reverse transcriptase.

Note: AZT is used both as a prophylaxis (prevention of disease) and also for the treatment of the retroviral infection. It is a very potent drug in preventing the mother to child transmission of HIV during pregnancy.