1039. New territory for antimicrobial stewards: weight based dosing in the obesity era
Session: Poster Abstract Session: Stewardship: Improving Treatments
Friday, October 4, 2013
Room: The Moscone Center: Poster Hall C
Background: Little is known about the impact of pediatric obesity on antimicrobial pharmacokinetics (PK) and pharmacodynamics (PD) despite evidence that this epidemic affects 17% of those 2-19 years of age in the US.  Dosing recommendations are based on PK data developed in healthy adults and adapted to children, based on a mg/kg dosing regimen. The number of children at risk of exceeding the current maximum adult dose (AD) of antibiotics based on pediatric weight based recommendations has not been defined. Objective: Describe the scope of the problem by identifying the number of children at risk for receiving antimicrobials that exceed the maximum AD based on the weight distribution in a large pediatric cohort.

Methods: This is a retrospective study using de-identified patient information to assess prescribing patterns of commonly used antimicrobials in children who visited the Children’s Mercy Hospital emergency department (CMH ED) from 1/1/2012 to 12/31/12. Weight and ages of all children seen in the ED who received one of the following antibiotics (amoxicillin, amoxicillin-clavulanate, cefdinir, ceftriaxone, cephalexin, TMP-SMX, clindamycin and linezolid) were obtained. Age groups were used to assess risk: Group 1 (2-5 years), Group 2 (6-10 years), Group 3 (11-15 years) and Group 4 (>16 years).

Results: Among 78,695 total ED visits, a study antibiotic was prescribed 9820 times (12%). Amoxicillin (42%), cephalexin (13%), clindamycin (12%), and TMP-SMX (9%) were most commonly prescribed. The percentage who would have exceeded maximum AD varied by age group and antibiotic assessed.  Those in Groups 3 and 4 were at greatest risk. Children (group 3, 4) who received cefdinir (71, 100%), clindamycin (40, 75%), TMP-SMX (66, 79%) and cephalexin (86, 100%) would have been most impacted.

Conclusion: :  A substantial portion of children > 10 years of age would exceed the current AD recommendations for commonly used antimicrobials with the 11-15 year olds being high risk.  The pre-pubescent adolescent may not exhibit PK parameters similar to adults resulting in potential suboptimal dosing that could impact therapeutic outcomes and increase adverse event profiles. Further investigation is needed to define such parameters to optimize antimicrobial therapy.

Jennifer Goldman, MD, Pediatric Infectious Diseases, Children's Mercy Hospital and Clinics, Kansas City, MO, Leslie Stach, PharmD, BCPS, Children's Mercy Hospitals and Clinics, Kansas City, MO and Mary Anne Jackson, MD, FIDSA, Children's Mercy Hospital, Kansas City, MO

Disclosures:

J. Goldman, None

L. Stach, None

M. A. Jackson, None

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