Zidovudine Use for HIV treatment, Mechanism of action
Zidovudine chemically thymidine analog. Another name is azidothymidine, the abbreviated name is AZT. It is mainly used for the treatment of HIV/AIDS and also use prophylaxis treatment . AIDS is disease caused by HIV virus. Doctor gave to pregnant women for preventing AIDS to new born baby.
Zidovudine is use for the treatment of HIV with a combination of other 2 antiretroviral medicine for more effective action so it is called triple-drug regimen. It increases the patients life span but it is not cure the HIV completely. this medicine is immune status simultaneously increase the CD4+ cell count progressively. Due to immune status increase less chance to infected other disease.
Side effect of Zidovudine
A most common side effect include headache, fever, nausea, vomiting, trouble sleeping, loss of appetite may occur, liver problems, muscle damage, high blood lactate level.
Sometimes skin disease is are may occur like a rash , peeling of the skin, hives, itching, swallowing the difficulty , swelling of the eye , face, tongue, lips, and throat.
Some symptoms of severe leukemia or neutropenia like unusual bleeding or bruising, fever, chills and other infection, pale of skin.
Mechanism of action
Zidovudine is a prototype medicine. it converts in the host cell to zidovudine triphosphate by the process phosphorylation. Zidovudine triphosphate inhibits the virus reverse transcriptase. HIV virus having single-stranded viral RNA which is converted into double-stranded proviral DNA by the help of reverse transcriptase enzyme. This proviral DNA is entered in to chromosomal DNA of the host cell by the help of another enzyme integrase. Due to this action viral DNA are replicate continuously. virus structural protein is produced in the form of a polyprotein. finally assembly all other particles and mature after some polyprotein by the help of enzyme protease.
Zidovudine has prevented the formation of new viral DNA by inhibiting the enzyme reverse transcriptase but it have no effect on the viral DNA which is already developed or integrate into to the host chromosome. It most effective only retrovirus. Zidovudine is also entered into viral DNA and terminate the chain elongation . after taking for log time around 1-2 year it produces resistance power. if you take this medicine without a combination of other then it increases the resistance power in 1-2 year.
It is have three metabolism pathway lets discuss this
This medicine is prodrug so it is phosphorylation in lymphocytes to show the antiviral action . in this pathway very less amount of medicine is metabolized.
Another pathway this medicine metabolism is glucuronidation and metabolite is excreated by the kidney. Glucoronidation is occour by the enzyme present in the human liver.
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 take zidovudine plama concentration of AMT is 10-15 % .
Oral absorption of AZT is rapid . bioavailability is aproxmately 65%. It mainly excreat through the body by hepatic glucuronidation. 15-20% of unchanged AZT is excreated through urine. Plasma protein binding capacity is 30%. It easily cross the placenta of women. And it is mostly found in the milk of mother.
Dose of Zidovudine
AZT is available in the two type dosage form oral admiration and I.V administration . among this oral administration is show better effect . but I.V injection is show good effect in the post exposer prophylaxis treatment.
During delivery 2mg /Kg loading dose is required .
Adult dose is 300 mg after taking food . maximum dose for children is 200 mg every 6-8 hour.
Some brand name 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 excreation of your body.
It produce toxicity due to inhibit of mitochondrial DNA polymerase ¥. It has more affinity towards the zidovudine triphosphate . anaemia and neutropenia are most important adverse effect show in the AZT medicine. Some other adverse effect are show like nausea , anorexia, abdominal pain ,headache, insomnia and myalgia are shown in the staring of dose latterly it goes.
Paracetamol are increase the toxicity of AZT because it competing glucuronidation. Azole antifungal also inhibit AZT metabolism. Stavudine is also compiting with AZT for the activation of pathway.
Some most importace condition to take this medicine
In the medical staff are more chances of affecting HIV . because they are always work in this type of envirment . accidentally exposed to HIV infection by needle stick or other sharp injury or contact with blood . if any one is expose to HIV affected patient then immediately they can take zidovudine to avoid the replication of virus cell.it gives the better effect.
Perinatal HIV prophylaxis
HIV may be transmitted form the mother to child either through placenta or breastfeeding . more chance to infect the child to her mother in birth procress. So doctor are inject AZT to women before surgery .
Storage condition of Zidovudine
This medicine is store in the room temperature, which is below 25°C. Keep this medicine lock and key for children for the safety purpose. If the medicine box or container pack is unseal then don’t take this medicine . container pack is containing desiccant which is help prevent the moisture don’t through desiccant before finish medicine . Before taking this medicine check the expiry of the medicine . expiry date in mention in the box of medicine.
AZT first discovers in 1964 and approved by the United States in 1986. 1986 HIV first treatment by the AZT. Azidothymidine was first discovered at the Michigan cancer foundation in 1964. But the aim of synthesis was the treatment of cancer treatment but it shows negative results further studied about this drug identified this medicine is show antiretroviral effect.
In the 1983 pasture institute in paris identified the HIV virus then Samuel Broder, Hiroaki Tetsuya and Robert archon are started developing the therapy of aids/ HIV virus.
In the India ZIDOVIR 300 mg tablet price is 136 rupees which is manufacture by the Cipla Ltd. And also ZIDOVUDINE 300 mg tablet manufacturing cipla price 187 rupees for 10 Tablet .Cipla manufacture ZIDOVIR 50 mg solution 100 ml in the price 73 rupees.
Emcure pharmaceutical Pvt Ltd manufacture ZIDINE 300 mg tablet price 933 rupees for 60 tablets.
In USA Zidovudine 300 mg tablet 18.16 $ for 60 tablet .one tablet price is around 0.30-0.68 $ according to the brand or manufacturing company.