From the Guidelines
For bone infections, fluoroquinolones are generally preferred over Bactrim (trimethoprim-sulfamethoxazole) due to their superior bone penetration. The choice between Trimethoprim/Sulfamethoxazole (Bactrim) and Fluoroquinolones for bone penetration depends on several factors, including the causative pathogen, patient comorbidities, and potential side effects.
Key Considerations
- Fluoroquinolones, such as ciprofloxacin and levofloxacin, achieve high tissue concentrations in diabetic foot infections (DFIs) [ 1 ], which suggests they may also have good bone penetration.
- The bioavailability of oral antibiotics, including fluoroquinolones and trimethoprim/sulfamethoxazole, is generally excellent [ 1 ], making them suitable for treating bone infections.
- However, fluoroquinolones are associated with an increased risk of adverse effects, such as Clostridium difficile disease and tendon rupture [ 1 ].
Treatment Recommendations
- For bone infections, the typical dosage for ciprofloxacin is 500-750 mg orally twice daily, while levofloxacin is usually given as 500-750 mg once daily.
- Treatment duration for bone infections is typically 6-8 weeks, but can extend to 12 weeks or more in severe cases.
- If methicillin-resistant Staphylococcus aureus (MRSA) is suspected or confirmed, Bactrim might be preferred as it has excellent activity against this pathogen.
Important Considerations
- When using fluoroquinolones, be aware of potential side effects, such as tendon rupture, especially in older patients or those on corticosteroids.
- Avoid use in patients with a history of seizures or those taking medications that can prolong the QT interval.
- In cases where fluoroquinolones are contraindicated or the infection is known to be caused by MRSA, Bactrim can be a suitable alternative, typically dosed at 1-2 double-strength tablets twice daily for adults.
From the Research
Comparison of Trimethoprim/Sulfamethoxazole and Fluoroquinolones for Bone Penetration
- The penetration of antibiotics into bone tissue is crucial for the effective treatment of bone infections.
- Studies have shown that fluoroquinolones have excellent tissue penetration, including bone penetration 2.
- A review of pharmacokinetic studies found that most antibiotics, including fluoroquinolones and trimethoprim/sulfamethoxazole, showed good penetration into bone and joint tissues, reaching concentrations exceeding the minimum inhibitory concentrations (MIC) of common pathogens 3.
- Specifically, moxifloxacin, a fluoroquinolone, has been shown to achieve high bone concentrations and rapid equilibrium between bone and serum, with a median bone-to-serum concentration ratio of 80% for cortical bone and 78% for cancellous bone 4.
- In comparison, trimethoprim/sulfamethoxazole has been found to have good penetration into bone tissue, but the extent of penetration may vary depending on the specific study and methodology used 3, 5.
- Overall, both fluoroquinolones and trimethoprim/sulfamethoxazole appear to have good bone penetration, but the specific characteristics and advantages of each antibiotic should be considered when selecting treatment for bone infections 2, 3, 4, 5.
Key Findings
- Fluoroquinolones have excellent tissue penetration, including bone penetration 2.
- Moxifloxacin achieves high bone concentrations and rapid equilibrium between bone and serum 4.
- Trimethoprim/sulfamethoxazole has good penetration into bone tissue, but the extent of penetration may vary 3, 5.
- Both fluoroquinolones and trimethoprim/sulfamethoxazole appear to have good bone penetration, but specific characteristics and advantages should be considered when selecting treatment for bone infections 2, 3, 4, 5.
Bone Penetration Characteristics
- Fluoroquinolones: excellent tissue penetration, including bone penetration 2.
- Moxifloxacin: high bone concentrations, rapid equilibrium between bone and serum, median bone-to-serum concentration ratio of 80% for cortical bone and 78% for cancellous bone 4.
- Trimethoprim/sulfamethoxazole: good penetration into bone tissue, but extent of penetration may vary 3, 5.