Children

AZT (zidovudine, Retrovir) is often prescribed to children and infants. It was licensed for use in a syrup formulation in HIV-infected children aged over three months in 1990. The recommended dose for children has been 360 to 480 mg/m² per day, divided into three or four doses, with a maximum of 200mg per dose.^[1] Large volumes of the syrup are not well tolerated by older children.

In 2008, the US FDA approved new dosing guidelines that allow for twice or thrice daily dosing in children 6 weeks to 18 years. Dosage can be calculated by weight or by body surface area. The new label has recommendations for twice daily or three times daily dosing by weight or by body surface area. Capsules and tablets have also been approved for use in children who are able to swallow them.

The new guidelines advise that children 4 kg to <9 kg receive 24mg/kg daily, administered as 12 mg twice daily or 8 mg three times a day. Children from 9 to <30 kg should receive 18 mg daily (divided doses of 9 bid or 6 three times daily), and children 30 kg or more should receive 600 mg daily, dosed at 300 mg twice a day or 200 mg three times a day.

Alternatively, dosing for zidovudine can be based on body surface area (BSA) for each child. The recommended oral dose is 480 mg/m²/day in divided doses (240 mg/m² twice daily or 160 mg/m² three times daily). In some cases the dose calculated by mg/kg will not be the same as that calculated by BSA.

Side-effects of AZT in children are similar to adults, with anaemia being the most common.^[2][3]

Combivir is only approved for use in children over 12 years of age, while Trizivir is not approved for use in those younger than 18 years.