Persons who are using drugs that suppress the immune system (., corticosteroids) are more susceptible to infections than healthy individuals. Chickenpox and measles , for example, can have a more serious or even fatal course in susceptible children or adults using corticosteroids. In children or adults who have not had these diseases or been properly immunized, particular care should be taken to avoid exposure. How the dose, route, and duration of corticosteroid administration affect the risk of developing a disseminated infection is not known. The contribution of the underlying disease and/or prior corticosteroid treatment to the risk is also not known. If a patient is exposed to chickenpox, prophylaxis with varicella zoster immune globulin (VZIG) may be indicated. If a patient is exposed to measles, prophylaxis with pooled intramuscular immunoglobulin ( IG ) may be indicated (see the respective package inserts for complete VZIG and IG prescribing information). If chickenpox or measles develops, treatment with antiviral agents may be considered.
The growth of children and adolescents receiving orally inhaled corticosteroids, including QVAR, should be monitored routinely (., via stadiometry). If a child or adolescent on any corticosteroid appears to have growth suppression, the possibility that he/she is particularly sensitive to this effect should be considered. The potential growth effects of prolonged treatment should be weighed against clinical benefits obtained and the risks associated with alternative therapies. To minimize the systemic effects of orally inhaled corticosteroids, including QVAR, each patient should be titrated to his/her lowest effective dose [see Dosage and Administration ( )] .
Denatured TBG does not bind iodothyronines but can be detected with antibodies that recognize the primary structure of the molecule (23). In euthyroid adults with normal TBG concentration, about one-third of the molecules carry thyroid hormone, mainly T4. When fully saturated, it carries about 20 µg of T4/dl of serum. The biologic half-life is about 5 days, and the volume of distribution is similar to that of albumin (34,35) (Table 1). TBG is cleared by the liver. Loss of sialic acid accelerates its removal through interaction with the asialo-glycoprotein receptors reducing the half live by 500-fold (21). However, it is unknown whether desialylation is a required in the normal pathway of TBG metabolism.