From the Guidelines
For the treatment of osteomyelitis with a methicillin-susceptible Staphylococcus aureus (MSSA) culture, oral antibiotics may be considered as an alternative to intravenous therapy in certain cases.
Recommended Oral Antibiotics
- Cephalexin: 500mg every 6 hours
- Dicloxacillin: 500mg every 6 hours
- Clindamycin: 300-450mg every 6 hours, particularly in patients with a history of allergy to penicillins or cephalosporins 1 These regimens are recommended with a treatment duration of 4-6 weeks.
Important Considerations
- Dosages need to be adjusted based on patients’ renal and hepatic function 1
- Antimicrobials should be chosen based on in vitro susceptibility as well as patient allergies, intolerances, and potential drug interactions or contraindications to a specific antimicrobial 1 It is essential to note that the choice of antibiotic should be guided by the results of culture and susceptibility testing, as well as the patient's clinical condition and medical history.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION The penicillinase-resistant penicillins are available for oral administration and for intramuscular and intravenous injection. Bacteriologic studies to determine the causative organisms and their sensitivity to the penicillinase-resistant penicillins should always be performed. In severe staphylococcal infections, therapy with penicillinase-resistant penicillins should be continued for at least 14 days.
The effective oral antibiotics for osteomyelitis with a culture positive for MSSA (Methicillin-Sensitive Staphylococcus aureus) are:
- Dicloxacillin 2 Other options may be considered based on susceptibility patterns and clinical judgment, but dicloxacillin is a directly mentioned option for MSSA infections. Note that clindamycin 3 may also be effective, but its use should be reserved for penicillin-allergic patients or other patients for whom a penicillin is inappropriate.
From the Research
Effective Oral Antibiotics for Osteomyelitis with MSSA
- Cephalexin is an effective oral antibiotic for treating osteomyelitis with MSSA, with an 87% treatment success rate without recurrence during a median follow-up of 119 days 4.
- Levofloxacin may not be as effective as parenteral antibiotics like nafcillin for treating MSSA osteomyelitis, with a lower percentage of infected tibias demonstrating significant improvement 5.
- Oral β-lactams, such as cephalexin, may be a safe option for switching from parenteral antibiotics in certain adult patients with MSSA vertebral osteomyelitis, with no significant difference in success rates compared to parenteral β-lactams only 6.
- Ceftriaxone and oxacillin have similar treatment success rates for MSSA osteoarticular infections, with ceftriaxone being less expensive for outpatient therapy and having fewer treatment-related adverse events 7.
- Cefadroxil has similar in vitro activity to cephalexin against MSSA isolates from pediatric musculoskeletal infections, suggesting it could be an alternative oral antibiotic for treating MSSA infections 8.
Key Considerations
- The choice of oral antibiotic for osteomyelitis with MSSA should be based on the specific patient population, infection site, and antibiotic susceptibility patterns.
- Combination therapy with parenteral and oral antibiotics may be necessary for optimal treatment outcomes.
- Further research is needed to determine the optimal dose and frequency of oral antibiotics like cefadroxil and cephalexin for treating serious MSSA infections.