Raltegravir (Isentress), an integrase strand transfer inhibitor approved for the treatment of HIV in adults in 2007, has now been approved for use in children and adolescents two to 18 years of age. Raltegravir is taken orally twice a day and is available in two forms: one that's swallowed and one that's chewed. The two formulations contain different doses; they're not bioequivalent and cannot be used interchangeably.

The chewable form (available in 25-mg and 100-mg strengths) is only for children two to 11 years of age. The appropriate dosage is based on the age and weight of the child. The formulation for children 12 years old and older and adults is 400 mg per tablet.

Raltegravir is used in combination with other antiretroviral drugs, never as monotherapy. In children, as in adults, notable adverse effects are insomnia, headache, elevated creatine kinase levels, and immune reconstitution syndrome. Raltegravir carries the risk of severe and life-threatening skin reactions, such as Stevens-Johnson syndrome, although such reactions are rare. To see the complete prescribing information for raltegravir, go to http://1.usa.gov/y8gIF3.