Zidovudine Mechanism of Action | Uses and Side Effects

Chemically zidovudine mechanism of action is a thymidine analogue. Another name is azidothymidine, abbreviated name is AZT. It is mainly used for the treatment of HIV/aids and also uses prophylaxis treatment. Aids is a disease caused by the HIV virus. Doctors are given to pregnant women to prevent Aids in newborn babies.

Zidovudine is used for the treatment of HIV with a combination of other 2 antiretroviral medicines for more effective action so it is called a triple-drug regimen. It increases the patient’s life span but it does not cure the HIV completely. This medicine’s immune status simultaneously increases the CD4+ cell count progressively. Due to immune status increase less chance to infected with other disease. 

Side Effects of Zidovudine

The most common side effects of zidovudine mechanism of action include headache, fever, nausea, vomiting, trouble sleeping, loss of appetite, liver problems, muscle damage, and high blood lactate level. Sometimes skin diseases may occur like rash, peeling of the skin, hives, itching, swallowing difficulty, and swelling of the eye, face, tongue, lips, and throat. Some symptoms of severe leukaemia or neutropenia like unusual bleeding or bruising, fever, chills and other infections, and pale skin.

Zidovudine Mechanism of Action

Zidovudine mechanism of action shows that it’s a prototype medicine. it converts in the host cell to zidovudine triphosphate by the process of phosphorylation. Zidovudine triphosphate inhibits the virus reverse transcriptase. HIV virus has single-stranded viral RNA which is converted into double-stranded proviral DNA with the help of reverse transcriptase enzyme. This proviral DNA enters into to chromosomal DNA of the host cell with the help of another enzyme integrase. Due to this action viral DNA is replicated continuously. virus structural proteins are produced in the form of a polyprotein. finally assembly all other particles and mature after some polyprotein with the help of enzyme protease.

Zidovudine mechanism of action prevents the formation of new viral DNA by inhibiting the enzyme reverse transcriptase but it has no effect on the viral DNA which is already developed or integrated into the host chromosome. It is most effective only for retrovirus. Zidovudine also enters into viral DNA and terminates the chain elongation. after taking for log time of around 1-2 years it produces resistance power. if you take this medicine without the combination of others then it increases the resistance power in 1-2 years.

Zidovudine Mechanism of Action


It has three metabolism pathways let’s discuss this.

1. This medicine is prodrug so it is phosphorylated in lymphocytes to show antiviral action. in this pathway very small amount of medicine is metabolized.

2. Another pathway in the zidovudine mechanism of action is glucuronidation and metabolite is excreted by the kidney. Glucuronidation is caused by the enzyme present in the human liver.

3. Last metabolism by reduction of azido moiety which is 3’– amino -3’-deoxythymidine otherwise called AMT. 3’– amino -3’-deoxythymidine formation is probably mediated by both cytochrome P450 enzyme and NADPH- cytochrome P450 reductase. If the patient takes zidovudine plasma concentration of AMT is 10-15 %.

Oral absorption of AZT is rapid. bioavailability is approximately 65%. It is mainly excreted through the body by hepatic glucuronidation. 15-20% of unchanged AZT is excreted through urine. Plasma protein binding capacity is 30%. It easily crosses the placenta of women. And it is mostly found in the milk of the mother.

Dose of Zidovudine

By the zidovudine mechanism of action, the dose of zidovudine is available in two types of dosage form oral admiration and I.V administration. Among these oral administration shows a better effect but I.V. injection shows a good effect in the post-exposure prophylaxis treatment.

During delivery 2mg /Kg loading dose of zidovudine is required. The adult dose is 300 mg after taking food. The maximum dose for children is 200 mg every 6-8 hours.

Some brand names are RETROVIR, ZIDOVIR 100 MG capsule, 300 mg tablets, 50 mg/5ml syrup and VIRO-Z, ZIDOMAX, ZYDOWIN 100 MG capsule, 300 mg tablets.

Take plenty of water if you take this medicine for the excretion of your body.

Adverse Effect

The zidovudine mechanism of action produces toxicity due to inhibiting of mitochondrial DNA polymerase. It has more affinity towards the zidovudine triphosphate. Anaemia and neutropenia are the most important adverse effects shown in AZT medicine. Some other adverse effects, like nausea, anorexia, abdominal pain, headache, insomnia and myalgia are shown at the start of the dose latterly it goes.

Paracetamol increases the toxicity of AZT because it competes with glucuronidation. Azole antifungal also inhibits AZT metabolism. Stavudine is also competing with AZT for the activation of pathway.

Some most important conditions for taking this medicine

Post-exposure prophylaxis:

In the medical staff, there are more chances of affecting HIV by the zidovudine mechanism of action. because they are always working in this type of environment. Accidentally exposed to HIV infection by needle stick or other sharp injury or contact with blood. If anyone is exposed to the affected patient then immediately they can take zidovudine to avoid the replication of the virus cell. It gives a better effect.

Perinatal HIV prophylaxis:

HIV may be transmitted from the mother to the child either through the placenta or breastfeeding. more chance to infect the child to her mother in the birth process. So doctors inject AZT into women before surgery.

Zidovudine Mechanism of Action

HIV Treatment Zidovudine:

The brilliance of the zidovudine mechanism of action lies in its ability to thwart the virus’s progress by inhibiting the reverse transcriptase enzyme, a key player in HIV’s replication machinery. By doing so, AZT effectively puts the brakes on the virus’s capacity to generate copies of itself, leading to a reduced viral load in the bloodstream and a slowing of HIV’s relentless march.

HIV treatment zidovudine is typically not a standalone hero but a crucial part of a dynamic ensemble cast, teaming up with other antiretroviral medications to create the formidable regimen known as highly active antiretroviral therapy.

This potent combination has not only extended the lifespans of those living with HIV but also significantly improved their overall quality of life.

Storage Condition of Zidovudine

Zidovudine mechanism of action refers to storing at room temperature, which is below 25°C. Keep this medicine lock and key for children for safety purposes. If the medicine box or container pack is unsealed then don’t take this medicine. The container pack contains desiccant which helps prevent moisture don’t through desiccant before finishing medicine. Before taking this medicine check the expiry of the medicine. The expiry date is mentioned in the box of medicine.


AZT was first discovered in 1964 and approved by the United States in 1986. HIV’s first treatment by zidovudine mechanism of action was done in 1986. Azidothymidine was first synthesized at the Michigan Cancer Foundation in 1964. But aim of the synthesis was to treat cancer treatment but it showed negative results further studies of this drug identified this medicine has an antiretroviral effect.

The 1983 Pasture Institute in Paris identified the virus then Samuel Broder, Hiroaki Mitsuya and Robert Yarchoan started developing the therapy of aids/ HIV virus.

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