Dear Dr Katherine,

Baby is now 2 months old and taking AZT at 2mg per kg every 6 hours, 3TC at 4 mg per kg every 12 hours. Switching to the pediatric dosing according to surface area for AZT is nearly 4 times more AZT than based on the mg per kg dosing. This is a huge difference in dosing. Would it not be better to graually increase the dosing over a couple weeks or so? The guidelines are not clear at all concerning this and at what age should the switch over begin at? The guidelines say the usual dose is 160 mg per M sq, but can range from 90 to 180 mg per M sq. every 8 hours. If baby is going to be taking AZT, 3TC and NFV together would you recommend the lower 90 mg dose for AZT?

Thank you for your help. AO

By 1-2 months of age, we usually use pediatric rather than the newborn doses of ZDV. I would advise using the higer dose ZDV in order to get better levels and CNS coverage and most commonly use ZDV 240 mg/m2 given every 12 hours.