AZT (zidovudine, Retrovir) may be taken twice or three times a day. Most people generally find twice daily regimens easier to manage.

The daily dose is 500 or 600mg. AZT is usually taken as one 250 mg capsule twice a day, but 100mg capsules are also available for dose variations. A reduced dose of 200mg twice a day may also be safe and effective in patients with low body weight of less than 60kg^[1]. A 300mg capsule has been discontinued in the United Kingdom due to low demand.

AZT is also available as a syrup and as a solution for infusion into a vein. Both of these are at the concentration of 10mg/ml.

AZT may be taken with or without food. However, to achieve maximum AZT levels in the body the drug should be taken on an empty stomach, although this is not essential. It is important to take the drug as prescribed in order to maintain the right level of the drug in the blood. If blood levels of the drug fall too low, this will allow the development of resistance to AZT and may affect future treatment options.

People with low white blood cell counts or haemoglobin levels should not take AZT. Patients with severe kidney problems should take a reduced dose of AZT.