Children

The recommended dose of abacavir (Ziagen) for infants and children between three months and twelve years of age is 8mg/kg twice a day, up to a maximum dose of 600mg a day.^[1] There is limited data to suggest that a dose of 2mg/kg twice daily may be suitable for infants 30 days or younger.

Abacavir does not need to be dosed with food. Patients who are HLA-B*5701 positive should not use abacavir; testing should be considered prior to therapy initiation.

The 48-week PENTA 5 study demonstrated that 3TC (lamivudine) with ABC (abacavir) offered better virological suppression and growth than did regimens with a NNRTI backbone of either AZT (zidovudine Retrovir)/ 3TC or AZT and abacavir. It should be preferred as a first-line NRTI backbone.^[2]

After five years of follow-up, 31% of children who started treatment with abacavir and 3TC had changed regimens versus 39% of the children initially randomised to AZT/3TC, and 46% of children taking AZT and abacavir. Patients taking abacavir/3TC were significantly less likely to change therapy with an undetectable viral load than were patients in either of the other two treatment arms, indicating the tolerability of the abacavir/3TC regimen. 

Researchers involved in the PENTA 5 study considered the combination of abacavir and 3TC to be a particularly attractive option for children because both drugs can be given as tolerable-tasting liquids twice a day in small volumes, essential features of any medication for children. Investigators noted that a fixed dose combination 3TC/abacavir pill for children is needed.

The PENTA 13 study showed that once-daily abacavir might be a safe and effective option for the treatment of HIV-infected children, with similar drug levels to children taking abacavir twice a day.^[3] However, more data are needed before this can become a recommended treatment option.