Drug Information


    

       











Pharmacokinetics


Zidovudine is rapidly absorbed from
the gastrointestinal tract and undergoes first-pass hepatic metabolism
with a bioavailability of about 60 to 70%. Peak plasma concentrations
occur after about 1 hour. Absorption is delayed by administration with
food, but bioavailability is probably unaffected. It crosses the
blood-brain barrier producing CSF to plasma ratios of about 0.5. It
crosses the placenta and is distributed into breast milk. Plasma protein
binding is reported to be 34 to 38%. The plasma half-life is about 1
hour.


Zidovudine is metabolised intracellularly to the antiviral triphosphate.
It is also metabolised in the liver mainly to the inactive glucuronide
and is excreted in the urine as unchanged drug and metabolite. As there
is some tubular secretion, probenecid can delay excretion.


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Indication
& Dosage



Oral



ASYMPTOMATIC AND SYMPTOMATIC HIV DISEASE, AIDS-RELATED COMPLEX:
100mg 4
hourly or 200 mg 8 hourly. Dose may be increased to 1000mg/day in
patients with neurological disease. Children over 3 months: 180mg/m2 4
times a day not exceeding 200mg q.i.d 


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Action



Zidovudine is a thymidine
analogue. It is phosphorylated in the body to zidovudine triphosphate
which is the active form and which inhibits HIV replication. Zidovudine
inhibits the key enzyme reverse transcripatase. Human DNA polymerase is
inhibited only at a concentration 100times morre than that required to
inhibit viral reverse transcriptase.


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Interactions


Dapsone, Pentamidine, Amphotericin B, Flucytosine, Vincristine,
Vinblastine, Adriamycin, Interferon: Comitant use with drugs that are
nephrotoxic, cytotoxic or myelosuppressive may increase toxicity risk.

Trimethoprim: The serum levels of Zidovudine and its metabolite may be
increase.

Probenecid: Toxicity of either drug may be potentiated.

Acetaminophen: Increased incidence of granulocytopenia.

Acyclovie: Concomitant use may result in nerotoxicity.

Phenytoin: Altered phenytoin levels. Zidovudine clearance decreased by
phenytoin


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Adverse
Effects & Precaution

Anorexia, nausea, abdominal
pain, headache, anaemia, myalgia, insomnia, neutropenia. Rarely
convulsions and encephalopathy.


 

Precaution: Zidovudine should be used with
care in patients with anaemia or bone-marrow suppression. Dosage
adjustments may be necessary and it has been recommended that it should
not be used if the neutrophil count or haemoglobin value is abnormally
low. Care is also required in the elderly and in patients with reduced
kidney or liver function who may require reductions in dose. Patients
with risk factors for liver disease should be monitored during
treatment. Zidovudine treatment should be stopped if there is a rapid
increase in aminotransferase concentrations, progressive hepatomegaly,
or metabolic or lactic acidosis of unknown aetiology. It should not be
given to neonates with hyperbilirubinaemia requiring treatment other
than phototherapy or with markedly increased aminotransferase
concentrations.

Because of the haematological toxicity of zidovudine it is recommended
that, in patients with advanced symptomatic HIV disease taking oral
zidovudine, blood tests should be carried out at least every 2 weeks for
the first 3 months of treatment and at least monthly thereafter; blood
tests should be performed at least every week in those receiving
intravenous zidovudine. In patients with early HIV infection blood tests
may be performed less frequently (e.g. every 1 to 3 months).

Pregnancy: Not recommende.

Breast Feeding: Not known whether excreted in breast milk or whether it
reduces the potential for transmission of HIV in breast milk.

Man: May be used.


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Brand
avalible in market







RETROVIR

 

 

Burroughs
Wellcome

CAPS

100mg

100

5353.42

ZIDOVIR

 

 

Cipla

CAPS

10mg

10

150.00

 

 

 

 


Top

     






         

    
Drug Information
    

       

Pharmacokinetics

Zidovudine is rapidly absorbed from the gastrointestinal tract and undergoes first-pass hepatic metabolism with a bioavailability of about 60 to 70%. Peak plasma concentrations occur after about 1 hour. Absorption is delayed by administration with food, but bioavailability is probably unaffected. It crosses the blood-brain barrier producing CSF to plasma ratios of about 0.5. It crosses the placenta and is distributed into breast milk. Plasma protein binding is reported to be 34 to 38%. The plasma half-life is about 1 hour.
Zidovudine is metabolised intracellularly to the antiviral triphosphate. It is also metabolised in the liver mainly to the inactive glucuronide and is excreted in the urine as unchanged drug and metabolite. As there is some tubular secretion, probenecid can delay excretion.

Top
      

Indication & Dosage

Oral
ASYMPTOMATIC AND SYMPTOMATIC HIV DISEASE, AIDS-RELATED COMPLEX: 100mg 4 hourly or 200 mg 8 hourly. Dose may be increased to 1000mg/day in patients with neurological disease. Children over 3 months: 180mg/m2 4 times a day not exceeding 200mg q.i.d 

Top
      

Action

Zidovudine is a thymidine analogue. It is phosphorylated in the body to zidovudine triphosphate which is the active form and which inhibits HIV replication. Zidovudine inhibits the key enzyme reverse transcripatase. Human DNA polymerase is inhibited only at a concentration 100times morre than that required to inhibit viral reverse transcriptase.

Top
      

Interactions

Dapsone, Pentamidine, Amphotericin B, Flucytosine, Vincristine, Vinblastine, Adriamycin, Interferon: Comitant use with drugs that are nephrotoxic, cytotoxic or myelosuppressive may increase toxicity risk.
Trimethoprim: The serum levels of Zidovudine and its metabolite may be increase.
Probenecid: Toxicity of either drug may be potentiated.
Acetaminophen: Increased incidence of granulocytopenia.
Acyclovie: Concomitant use may result in nerotoxicity.
Phenytoin: Altered phenytoin levels. Zidovudine clearance decreased by phenytoin

Top
      

Adverse Effects & Precaution

Anorexia, nausea, abdominal pain, headache, anaemia, myalgia, insomnia, neutropenia. Rarely convulsions and encephalopathy.
 
Precaution: Zidovudine should be used with care in patients with anaemia or bone-marrow suppression. Dosage adjustments may be necessary and it has been recommended that it should not be used if the neutrophil count or haemoglobin value is abnormally low. Care is also required in the elderly and in patients with reduced kidney or liver function who may require reductions in dose. Patients with risk factors for liver disease should be monitored during treatment. Zidovudine treatment should be stopped if there is a rapid increase in aminotransferase concentrations, progressive hepatomegaly, or metabolic or lactic acidosis of unknown aetiology. It should not be given to neonates with hyperbilirubinaemia requiring treatment other than phototherapy or with markedly increased aminotransferase concentrations.
Because of the haematological toxicity of zidovudine it is recommended that, in patients with advanced symptomatic HIV disease taking oral zidovudine, blood tests should be carried out at least every 2 weeks for the first 3 months of treatment and at least monthly thereafter; blood tests should be performed at least every week in those receiving intravenous zidovudine. In patients with early HIV infection blood tests may be performed less frequently (e.g. every 1 to 3 months).
Pregnancy: Not recommende.
Breast Feeding: Not known whether excreted in breast milk or whether it reduces the potential for transmission of HIV in breast milk.
Man: May be used.

Top
      

Brand avalible in market

RETROVIR

 

 

Burroughs Wellcome

CAPS

100mg

100

5353.42

ZIDOVIR

 

 

Cipla

CAPS

10mg

10

150.00

 

 

 

 

Top
     

By |2022-07-20T16:42:47+00:00July 20, 2022|Uncategorized|Comments Off on Zidovudine

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