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INTRODUCTION

The objective of this chapter is to provide the general practitioner with an overview of the antibacterial medications currently available for clinical use in the pediatric population. The general mechanisms of antibiotic medications will be reviewed. An overview of antibiotic principles and basic pharmacokinetics and pharmacodynamics will be outlined with practical applications. Readers should refer to the disease-state chapters or a drug-dosing reference for up-to-date dosing information.

PRINCIPLES OF ANTIBACTERIAL THERAPY

It is important to have an understanding of likely organisms and their local susceptibility for the treatment of common infections. Additionally, when choosing between agents, one should consider the vaccine and immune status of the patient as well as medication properties such as absorption and penetration to the site of infection. This chapter reviews important concepts needed for choice of antibiotics in children. When considering an optimal antibacterial regimen, one must consider the multiple interactions between the patient, disease state, pathogen, and antibiotic. These factors are especially important when guideline- or evidence-based treatment regimens are contraindicated, due to patient factors or bacterial resistance. These considerations are highlighted in Box 8-1.

BOX 8-1.  Principles of Antibiotic Therapy

  • Infectious disease states and bacterial pathogens

    • Common bacterial etiologies vary by the infectious disease and site of infection, which are reviewed in the disease-specific chapters of this text.

  • Infectious disease states and patient characteristics

    • Patients may have baseline risk factors for developing infectious disease states, due to immune factors or abnormal anatomy.

  • Infectious disease states and antibiotic properties

    • Depending on the site of infection, the ability to cause bactericidal activity at concentrations tolerable by the patient may be important. This is especially true in meningitis, where the blood–brain barrier poses a challenge to medication penetration, and there is a consensus that bactericidal antibiotics must be used.249,250

    • The ability of an antibiotic to penetrate the site of infection is paramount. For instance, clindamycin is unable to cross the blood–brain barrier, barring its efficacy in meningitis.154

  • Antibiotic properties and bacterial pathogens

    • Pharmacodynamic targets of antimicrobials, and therefore dosing, may vary among species. For example, the fluoroquinolone exposure needed to treat pneumonia caused by Streptococcus pneumoniae is about fourfold lower than that needed to treat pneumonia caused by Pseudomonas aeruginosa.9,10

  • Patient characteristics and bacterial pathogens

    • Patients may have risk factors for differing etiologies, including immunocompromised state, vaccination status, and likely exposure to antibiotic-resistant organisms.

  • Patient characteristics and antibiotic properties

    • The ability to clear antibiotics may be increased relative to weight in young children, or decreased in patients with organ dysfunction. This may require additional consideration of route of elimination (renal vs hepatic) or dosing when choosing a regimen.

    • Tolerance of antibiotics may vary, due to allergic response, disease state (β-lactams may lower the seizure threshold), or drug–drug interactions, which are contraindicated (i.e., carbapenems’ ability to rapidly decrease serum concentrations of valproic acid derivatives to subtherapeutic levels).251,252

    • Enteral ...

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