Overview and uses

Zidovudine is a medicine used for HIV treatment. It is the first medicine developed in 1987 for HIV treatment. It is available only as a prescription medicine. Zidovudine is prescribed by a doctor in combination with other medicines for HIV treatment. This is done to increase the therapeutic efficacy of the medicines used in the treatment of HIV. Also, combination therapy reduces the risk of virus getting resistant to any one particular medicine.

Zidovudine does not cure HIV, but it slows down the progression of HIV within the body. HIV destroys CD4+ T Lymphocytes – a type of white blood cells (WBC) that gives immunity to the body. In other words, these cells protect the body against the infections or illness caused by various organisms like bacteria, viruses and other germs. Thus, one may conclude that HIV infection, if left untreated, may make the body susceptible to this infections/illness.

Brand names of Zidovudine

Retrovir, Zidovir, Viro-Z, Zidomax, Zydown.

Brand names of Zidovudine with other medicines

  • Trizivir contains Abacavir with Lamivudine and Zidovudine.
  • Triavir contains Zidovudine 300 mg with lamivudine 150 mg and nevirapine 200 mg.
  • Duovir contains zidovudine with lamivudine.

Pharmacological classification

Nucleoside reverse transcriptase inhibitor anti-retroviral drug

Indication (used for)

  • For the treatment of HIV-1.
  • For the prevention of mother to fetus transmission of HIV-1.
  • Zidovudine, along with at least 2 other anti-HIV medicines, is the first choice for post-exposure prophylaxis of HIV.
  • It also reduces neurological manifestations of AIDS and new Kaposi’s lesions do not occur. It also reduces the mortality amongst AIDS patients.
  • Slows down the progression of HIV infection including escalation of ARC complex to full-blown AIDS for a limited period of time.

Dosage form

Available as tablets and capsules for adults and as oral liquid for children. It is also available as intravenous injection in 10mg/ml strength.

Mechanism of action

Zidovudine – a thymidine analogue gets intracellularly converted into active form Zidovudine 5’- triphosphate, which terminates the elongation of proviral DNA. It gets incorporated into nascent DNA by reverse transcriptase but it lacks 3’-OH (hydroxyl) group.


Undergoes rapid first-pass metabolism by glucuronidation.


Adult dose for HIV infection

  • Oral dose: 300 mg every 12 hours or 200 mg every 8 hours.
  • Intra-venous: 1 mg/kg infused over 1 hour, to be repeated every 4 hours. The dose should not exceed 5 to 6 mg/kg of the body weight of the patient. Therapy should be continued until the patient tolerates or until the patient is switched over to another medicine.

Adult dose for prevention of maternal-fetal HIV – 1 transmission

  • Maternal dose:
    • 100 mg orally 5 times a day until the start of labor.
    • During labor and delivery, Zidovudine should be administered intravenously at 2 mg/kg of the total body weight over 1 hour followed by a continuous intravenous infusion of 1 mg/kg/hour of the total body until clamping of the umbilical cord.
  • Neonatal dose:
    • 2 mg/kg orally every 6 hours within 12 hours after birth and should be continued up to 6 weeks of age.
    • If oral dose cannot be administered, Zidovudine should be administered intravenously at 1.5 mg/kg every six hours, infused over 30 minutes.

Dose in patients with renal impairment

  • End stage renal impairment: for patients on hemodialysis or peritoneal dialysis:
    • 100 mg every 6 to 8 hours.

Pediatric dose

Pediatric dose (based on body surface area)

  • 240 mg/m2 twice a day or 160 mg/m2 three times a day, but not more than 480 mg/m2/day in divided doses.

Pediatric dose (based on body weight)

AgeBody weight in kgTotal daily doseDivided dose
6 weeks or more to less than 18 years4 kg or more to less than 9 kg 9 kg or more to less than 30 kg 30 kg or more24 mg/kg/day 18 mg/kg/day 600 mg/day12 mg/kg twice a day or 8 mg/kg thrice a day 9 mg/kg twice a day or 6 mg/kg thrice a day 300 mg twice a day or 200 mg thrice a day

Unwanted or side effects

  • Fatigue (tiredness), Malaise (feeling of discomfort or unease), Myalgia (pain in muscles), Nausea (feeling of vomit), Anorexia (loss of appetite), Headache and Insomnia (sleeplessness) are common complaints associated with Zidovudine treatment. However, these symptoms usually resolve within first few weeks of the treatment.
    • Ask your pharmacist for a suitable medicine and consult your doctor.
  • Bone marrow suppression (decrease in production of cells), mainly anemia (deficiency of hemoglobin or red blood cells) and granulocytopenia (decrease in the number of granulocytes – a type of WBC) are common in patients with low CD4 (a type of WBC) counts and advanced HIV stage of the disease.
    • Above mentioned symptoms can be confirmed by suitable blood tests. However, if you are observing shortness of breath, rapid heartbeat, pale skin, pale skin, dizziness and leg cramps, consult your doctor as soon as possible. These symptoms are associated with the above-mentioned condition.
  • Erythrocytic macrocytosis (a type of anemia) is common in almost 90% of the patients.
    • The above-mentioned condition can be confirmed by suitable blood tests. However, if you are observing shortness of breath, rapid heartbeat, pale skin, pale skin, dizziness and leg cramps, consult your doctor as soon as possible. These symptoms are associated with the above-mentioned condition.
  • Long time use of Zidovudine may lead to nail hyperpigmentation.
    • Do mention to your doctor about the changes in the nail linings when you consult your doctor.
  • Skeletal muscle myopathy
    • Symptoms for the above-mentioned condition are stiffness, aching, cramps, slowed reflexes and pain. Consult your doctor as soon as possible.
  • Serious hepatic toxicity with or without steatosis and lactic acidosis is common in female patients, obese patients and longtime use of Zidovudine.
    • Abdominal or stomach discomfort, diarrhea, fast and shallow breathing, sleepiness, tiredness or weakness, nausea and vomiting, pain in the upper right portion of the abdomen, rash, weight loss, yellowing of the skin and whites of the eye are some of the symptoms of the above-mentioned condition. Consult your doctor as soon as possible. Treatment with Zidovudine should be terminated if laboratory or clinical findings support the above-mentioned condition.
  • The most common side effect in neonates in the prevention of maternal-fetal transmission of HIV-1 is anemia and neutropenia as reported by clinical trials.

Hypersensitivity reaction can occur at any time during the therapy. But, most commonly it occurs within the first week to the sixth week from the initiation of the therapy. If you observe any other symptom that you suspect it to be associated with your anti-HIV treatment, consult your doctor as soon as possible.


Drug-drug interactions

  • Paracetamol increases Zidovudine toxicity.
  • Clotrimazole, Econazole, Miconazole, Oxiconazole, Ketoconazole, Fluconazole, Itraconazole, Voriconazole inhibits the metabolism of Zidovudine thereby causing an increase in the plasma concentration of Zidovudine.
  • Probenecid, Atovaquone and Valproic acid may increase the plasma concentration of Zidovudine.
  • Stavudine and Zidovudine exhibits mutual antagonism and should not be used concomitantly.
  • Concomitant use of Zidovudine and Doxorubicin should be avoided.
  • Coadministration of Zidovudine and Ribavirine should be avoided as it may cause exacerbation of anemia in HIV-1/HCV co-infected patients.

Any drug that undergoes metabolism by glucuronidation may interact with Zidovudine. Consult your doctor and pharmacist before taking any such medicines with Zidovudine.

Drug-food interactions

  • Food may slow down the absorption of Zidovudine but it does not affect the AUC (AUC reflects the extent and duration of body exposure to a particular medicine).
  • Can be taken regardless of food intake.


  • Cautious use of Zidovudine and strict monitoring is advised in those patients with preexisting anemia or granulocytopenia and in those patients who are taking drugs that are known to cause bone marrow suppression.
  • Zidovudine and Stavudine should not be taken together as they exhibit mutual antagonism.
  • Do not take any medicine containing Zidovudine if you are allergic to Zidovudine.

Other important information on Zidovudine

  • Zidovudine is absorbed rapidly and reaches peak plasma concentrations within 1 hour.
  • It undergoes rapid first-pass metabolism.
  • Systemic bioavailability of Zidovudine is almost 64%.
  • Zidovudine crosses blood-brain barrier relatively well and has a CSF: plasma ratio of 0.6.
  • Zidovudine can be detected in semen, breast milk and fetal tissue.
  • Zidovudine concentrations are higher in male in genital tract than in peripheral circulation.


  • Keep it in cool and dry place, away from direct heat and sunlight.
  • Keep it out of sight and reach of children.

Important information on anti-HIV and anti-AIDS medicines

Benefits of taking your anti-HIV medicines regularly

  • Sustained viral suppression.
  • Reduced risk of resistance.
  • Reduced risk of treatment failure.
  • Improved quality of life and overall health.
  • Reduced risk of HIV transmission.

Getting the most from your treatment

  • Precisely follow every advice given to you by your doctor and pharmacist regarding your medications. Take your dose regularly without missing out a single one.
  • Make all the necessary changes in your lifestyle and eating/food habits as advised by your doctor and pharmacist. This may include quitting smoking, alcohol, other substances of abuse, taking up exercise and some/many others that your doctor finds it best in your interest.
  • Do not make any changes in your dose unless suggested/recommended by your doctor.
  • Keep your regular appointments with your doctor so that the progress can be monitored. This may involve blood tests and other tests that a doctor finds necessary.
  • Consult your doctor if you develop an infection or an allergy after you start the treatment.
  • Consult your doctor if you feel low or even depressed. This is common especially after diagnosis and during the early stages of treatment.
  • Some people who have taken anti-HIV medicines for a long period of time may develop Osteonecrosis – a condition where bone tissue dies due to the reduced blood supply. This causes joint pain, stiffness and difficulty in movement. Consult your doctor if you if you notice any of these symptoms.
  • If you are going to take any operation/surgery or dental treatment, tell the doctor who is going to carry out operation/surgery or dental procedure about all the medicines that you are taking. If possible, carry your containers with you to the doctor even if it is empty.
  • If you buy any medicines, supplements including your vitamin supplements, herbal medicines or even the medicines that do not require a prescription, check with your pharmacist whether they can be taken along with your anti-HIV medicines or not.
  • Treatment of HIV is life-long. Continue taking your anti-HIV medicines even if you feel well. This should be done to keep your immune system healthy.

Forgot to take your medicine?

  • Forgetting a dose/frequent missed out doses may lead to viral resistance or treatment failure.
  • If you forget to take a dose, take it immediately as soon as you remember unless it’s almost the time for your next dose.
  • Do not take two doses at the same time to make up for the missed out dose.
  • If you are forgetting/missing your dose frequently or very often, try using pill boxes that are available as weekly or monthly dose boxes. Alternatively, you can also try posting reminder notes on places like doors of refrigerator, wardrobe, bathroom, side tables of your bed, above or below switchboards etc. You can also set a reminder on your cell phone.
  • If possible, ask your family members and friends to remind you of your dose.

Note: The sole purpose of every information shared on this article is to bring awareness. Do not use this information as a piece of medical advice or prescription advice or as a tool for the treatment, diagnosis or prevention of the disease.