Medication Summary
Infants in whom the clinical picture suggests afebrile pneumonia syndrome (APS) may benefit from a 10- to 14-day course of erythromycin. Newer macrolides and azalides are also effective and may be tolerated better (particularly azithromycin).
Antiviral therapy is used in the treatment of cytomegalovirus (CMV), but only when unusually severe disease or immunocompromise is present. Severe CMV pneumonitis may require CMV hyperimmunoglobulin and antiviral therapy.
Although ribavirin is available for the treatment of respiratory syncytial virus (RSV), disease sufficiently severe enough to merit treatment would not be APS and is beyond the scope of this discussion.
Antibiotics
Class Summary
In patients with APS, antibiotics are used for treatment of presumptive C trachomatis and U urealyticum infection. Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting. Whenever feasible, antibiotic selection should be guided by sensitivity testing of organisms isolated on blood cultures (although this occurs rarely in APS).
Erythromycin (E.E.S., E-Mycin, Eryc)
Erythromycin is a macrolide antibiotic, and cost, safety, and experience make erythromycin the drug of choice for APS. Erythromycin inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest.
Azithromycin (Zithromax)
Azithromycin is a macrolide antibiotic and may become the drug of choice for APS because of its safety profile, ease of use, and improved GI tract tolerability relative to erythromycin. The dose for infants younger than 6 months has not been established.
Clarithromycin (Biaxin)
Clarithromycin is a macrolide antibiotic that inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. It may be used as a substitute for erythromycin if compliance is a likely problem, as it is given qid rather than bid.
Antivirals
Class Summary
These agents are used to treat CMV infection. Ganciclovir is the drug of choice for documented CMV pneumonitis. Use foscarnet if a ganciclovir-resistant virus is identified or if adverse effects prevent ongoing use. Oral valganciclovir is under investigation for use in the treatment of congenital or neonatal CMV and recently has been approved for the prophylaxis of CMV disease in renal and/or heart transplant patients older than 3 months. [19]
Ganciclovir (Cytovene)
Ganciclovir is a synthetic guanine derivative that is the drug of choice for CMV infections, although experience with use in children is limited. An acyclic nucleoside analog of 2'-deoxyguanosine, ganciclovir inhibits replication of herpes viruses both in vitro and in vivo.
Levels of ganciclovir-triphosphate are as much as 100-fold higher in CMV-infected cells than in uninfected cells, possibly due to preferential phosphorylation of ganciclovir in virus-infected cells.
Foscarnet (Foscavir)
Foscarnet is an organic analog of inorganic pyrophosphate that inhibits replication of known herpesviruses, including CMV, HSV-1, and HSV-2. It inhibits viral replication at the pyrophosphate-binding site on virus-specific DNA polymerases. Poor clinical response or persistent viral excretion during therapy may be due to viral resistance.
Patients who can tolerate foscarnet well may benefit from initiation of maintenance treatment at 120 mg/kg/d early in treatment. Individualize dosing based on renal function status.
