Cefadroxil Use for Musculoskeletal Infections in an Academic Pediatric Hospital

Cefadroxil and cephalexin pharmacokinetics and pharmacodynamics in children with musculoskeletal infections

Cephalexin, a first-generation cephalosporin, is the first-line oral therapy for children with musculoskeletal infections due to methicillin-susceptible Staphylococcus aureus (MSSA). Cefadroxil, a similar first-generation cephalosporin, is an attractive alternative to cephalexin given its longer half-life. In this study, we describe the comparative pharmacokinetics (PK) and pharmacodynamics (PD) of cephalexin and cefadroxil in children with musculoskeletal infections. Children aged 6 months to 18 years with a musculoskeletal infection were enrolled in a prospective, open-label, crossover PK study and given single oral doses of cefadroxil (50-75 mg/kg up to 2,000 mg) and cephalexin (50 mg/kg up to 1,375 mg). Population PK models were developed and used for dosing simulations. Our primary PD target was the achievement of free antibiotic concentrations above the minimum inhibitory concentration (fT >MIC) for 40% of the day for MICs ≤ 4 mg/L. PK of cephalexin (n = 15) and cefadroxil (n = 14) were best described using a one-compartment, first-order absorption model, with a lag time component for cefadroxil. PK parameters were notable for cefadroxil's longer half-life (1.61 h) than cephalexin's (1.10 h). For pediatric weight bands, our primary PD target was achieved by cephalexin 25 mg/kg/dose, maximum 750 mg/dose, administered three times daily and cefadroxil 40 mg/kg/dose, maximum 1,500 mg/dose, administered twice daily. More aggressive dosing was required to achieve higher PD targets. Among children with musculoskeletal infections, oral cephalexin and cefadroxil achieved PD targets for efficacy against MSSA. Given less frequent dosing, twice-daily cefadroxil should be further considered as an alternative to cephalexin for oral step-down therapy for serious infections due to MSSA.

First-Generation Cephalosporins for Treatment of Acute Hematogenous Osteomyelitis in Children: A Study of Efficacy and Adverse Effects

Background

Acute hematogenous osteomyelitis (AHO) is a relatively infrequent but significant infection in pediatric patients. As Staphylococcus aureus is the most common cause of AHO, intravenous and oral first-generation cephalosporins are common therapies. Cephalexin is a commonly prescribed oral therapy for pediatric AHO, although it requires frequent dosing that may affect adherence. Cefadroxil is a comparable oral first-generation cephalosporin with a more desirable dosing schedule.

Methods

We reviewed pediatric patients admitted to Mayo Clinic between March 2002 and September 2020 for management of AHO who received treatment with a first-generation cephalosporin. We reviewed timing of oral therapy transition, therapy-associated adverse effects, and recurrence of disease after completion of therapy.

Results

There were 59 patients included in the study. There was similar occurrence of adverse effects in patients receiving cefadroxil and cephalexin, although use of cefadroxil coincided with more gastrointestinal adverse effects and leukopenia and use of cephalexin with more rash and neutropenia. One secondary treatment failure occurred in our study, in a patient receiving cephalexin for treatment of septic arthritis.

Conclusions

Cefadroxil may be a reasonable alternative oral therapy for methicillin-susceptible S aureus or culture-negative AHO in pediatric patients, particularly when a less frequent dosing schedule is desired. Future study with a larger sample size is warranted.