Oral Suppressive Therapy for Prosthetic Joint Infections
For suppressive therapy of prosthetic joint infections, use cephalexin 500 mg three to four times daily or dicloxacillin 500 mg three to four times daily for oxacillin-susceptible staphylococci; cotrimoxazole 1 double-strength tablet twice daily for oxacillin-resistant staphylococci; and cotrimoxazole 1 double-strength tablet twice daily for Enterobacteriaceae, with ciprofloxacin 250-500 mg twice daily reserved for Pseudomonas aeruginosa. 1
Staphylococcal Infections
Oxacillin-Susceptible Staphylococci
- Preferred: Cephalexin 500 mg orally three to four times daily 1
- Alternatives:
- Dicloxacillin 500 mg orally three to four times daily
- Cefadroxil 500 mg orally twice daily
- Amoxicillin-clavulanate 500 mg orally three times daily
- Clindamycin 300 mg orally four times daily 1
Oxacillin-Resistant Staphylococci (MRSA/MRSE)
- Preferred: Cotrimoxazole 1 double-strength tablet orally twice daily 1
- Alternative: Minocycline or doxycycline 100 mg orally twice daily 1
The tetracyclines (doxycycline/minocycline) demonstrate acceptable tolerability with adverse events in 18% of patients and treatment discontinuation in only 8%, with a failure rate of 28.2% over approximately 3 years of follow-up 2. This makes them reasonable second-line options when cotrimoxazole cannot be used.
Gram-Negative Organisms
Enterobacteriaceae
- Preferred: Cotrimoxazole 1 double-strength tablet orally twice daily 1
- Alternative: β-lactam oral therapy based on in vitro susceptibilities 1
Pseudomonas aeruginosa
- Only option: Ciprofloxacin 250-500 mg orally twice daily 1
Fluoroquinolones show superior efficacy for gram-negative prosthetic joint infections, with a 94% 2-year survival rate when used after debridement and implant retention 3. For Enterobacteriaceae specifically, fluoroquinolone use was associated with significantly lower failure rates (7.1% versus 37.5%) 4.
Critical Considerations
What NOT to Use
Rifampin alone or rifampin combination therapy is NOT recommended for chronic suppression 1. This is a critical pitfall—while rifampin is essential during the initial 3-month treatment phase for staphylococcal infections, it should not be continued as suppressive therapy due to rapid resistance development.
Dosing Adjustments
All antimicrobial dosages must be adjusted based on renal and hepatic function 1. Selection should account for in vitro susceptibility, patient allergies, intolerances, and potential drug interactions.
Monitoring Requirements
- Clinical and laboratory monitoring for both efficacy and toxicity is essential 1
- For fluoroquinolones: Monitor for QTc prolongation and tendinopathy 1
- For all antimicrobials: Monitor for Clostridium difficile colitis 1
- Consider monitoring liver function tests periodically 5
Duration of Suppressive Therapy
Suppressive therapy is typically indefinite when used 1. The decision to use suppressive therapy should be reserved for patients who are unsuitable for or refuse further surgical intervention (exchange revision, excision arthroplasty, or amputation) 1. This approach must balance the potential for progressive implant loosening and bone stock loss against the hazards of prolonged antibiotic therapy 1.
When to Consider Suppressive Therapy
The 2020 guideline suggests that suppressive therapy is most appropriate when:
- Contraindications to surgery exist
- Poor surgical outcome is anticipated
- Patient or surgeon preference against further surgery
- Stable prosthesis with biofilm-active antimicrobials available 5
The majority of infectious disease specialists use suppressive therapy for periprosthetic joint infections managed with debridement and implant retention, though significant practice variation exists 6.