Pharm

Zidovudine

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Zidovudine, Retrovir, ZDV, AZT

  • Mechanism
  1. Nucleoside Reverse Transcriptase Inhibitor
  2. Thymidine analogue
  3. Interferes with viral reverse transcriptase
  4. Interferes with elongation of the viral DNA chain
  • Pharmacokinetics
  1. Well absorbed from the gastrointestinal tract
  2. Glucuronidase added in the liver
  3. Excreted by the Kidney
  4. Crosses the blood-brain barrier and the placenta
  • Efficacy
  1. Delays the progression to AIDS and late HIV
  2. Increases CD4 Counts
  3. Suppresses viral replication in mild HIV (CD4 200-500)
  • Dosing
  1. Zidovudine 200 mg PO tid ($279/month) OR
  2. Zidovudine 300 mg PO bid
  • Adverse effects
  • General
  1. See nRTI for adverse effects attributed to the class
  2. Short term
    1. Headache
    2. Myalgia
    3. Malaise
    4. Fatigue
    5. Insomnia
    6. Nausea or Vomiting
    7. Bloating
    8. Dyspepsia
  3. Long term
    1. Nail and Oral Mucosa Hyperpigmentation
    2. Myopathy
  • Adverse Effects
  • Major toxicities
  1. Effects
    1. Anemia (Macrocytosis) (7% late, 1.8% early)
    2. Leukopenia (Neutropenia) (37% late, 4% early)
    3. Hepatitis
  2. Management of toxicity
    1. Interrupt treatment
      1. Results in reversal of Anemia and Neutropenia
    2. Specific Therapy
      1. Anemia: Give Erythropoietin
      2. Neutropenia: Give growth factors
    3. Persistent Anemia or Neutropenia
      1. Change therapy
  • Monitoring
  1. Advanced disease: Complete Blood Count each month
  2. Early disease: Complete Blood Count every 2-3 months
  • Resistance
  1. Develops 6 months into therapy