What is the best oral antibiotic regimen for a 73-year-old patient with Peripheral Vascular Disease (PVD) and Coronary Artery Disease (CAD) presenting with cellulitis of the lower leg, showing minimal improvement with Bactrim (Trimethoprim/Sulfamethoxazole), and a history of recurrent infections?

From the Guidelines

For a 73-year-old patient with peripheral vascular disease (PVD), coronary artery disease (CAD), and recurrent cellulitis showing minimal improvement with Bactrim, the best outpatient oral regimen would be a combination of amoxicillin-clavulanate (Augmentin) 875/125 mg twice daily for 5 days, as recommended by the most recent guidelines 1. If the patient has a penicillin allergy, consider clindamycin 300-450 mg four times daily. Given the patient's vascular compromise and history of recurrent infections, it is essential to address the underlying conditions that may have predisposed to the infection, such as tinea pedis, venous eczema, or trauma. The patient should elevate the affected limb, apply warm compresses, and monitor for signs of worsening infection (increasing redness, warmth, pain, fever, or streaking). Close follow-up within 48-72 hours is essential to assess response. This regimen targets both Staphylococcus (including MRSA) and Streptococcus species, which are common in cellulitis, particularly in patients with vascular compromise. The broader coverage addresses the likely polymicrobial nature of the infection in a patient with PVD. Key considerations in managing this patient include:

• Elevation of the affected area to promote gravity drainage of edema and inflammatory substances
• Treatment of underlying conditions that may have predisposed to the infection
• Monitoring for signs of worsening infection and adjusting the treatment plan as necessary
• Consideration of prophylactic antibiotics or other measures to reduce recurrences of cellulitis, as recommended by guidelines 1 and supported by studies 2.

From the FDA Drug Label

Complicated Skin and Skin Structure Infections Adult patients with clinically documented complicated skin and skin structure infections were enrolled in a randomized, multi-center, double-blind, double-dummy trial comparing study medications administered IV followed by medications given orally for a total of 10 to 21 days of treatment. The cure rates in clinically evaluable patients were 90% in linezolid-treated patients and 85% in oxacillin-treated patients A separate study provided additional experience with the use of ZYVOX in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. The cure rates in microbiologically evaluable patients with MRSA skin and skin structure infection were 26/33 (79%) for linezolid-treated patients and 24/33 (73%) for vancomycin-treated patients Diabetic Foot Infections Adult diabetic patients with clinically documented complicated skin and skin structure infections ("diabetic foot infections") were enrolled in a randomized (2:1 ratio), multi-center, open-label trial comparing study medications administered IV or orally for a total of 14 to 28 days of treatment The cure rates in the ITT population, the cure rates were 68. 5% (165/241) in linezolid-treated patients and 64% (77/120) in comparator-treated patients

The best oral antibiotic regimen for a 73-year-old patient with Peripheral Vascular Disease (PVD) and Coronary Artery Disease (CAD) presenting with cellulitis of the lower leg, showing minimal improvement with Bactrim (Trimethoprim/Sulfamethoxazole), and a history of recurrent infections is Linezolid 600 mg orally every 12 hours.

• Key points:
  • Linezolid has been shown to be effective in treating complicated skin and skin structure infections, including those caused by MRSA.
  • The cure rates for linezolid-treated patients were 90% in one study and 79% in another study for MRSA skin and skin structure infections.
  • Linezolid may be a suitable alternative for patients who have shown minimal improvement with other antibiotics, such as Bactrim. 3

From the Research

Oral Antibiotic Regimens for Cellulitis

Given the patient's condition, with Peripheral Vascular Disease (PVD) and Coronary Artery Disease (CAD) presenting with cellulitis of the lower leg and showing minimal improvement with Bactrim (Trimethoprim/Sulfamethoxazole), the choice of an oral antibiotic regimen is crucial.

• The patient's history of recurrent infections and the presence of predisposing risk factors such as PVD and CAD necessitate a rigorous approach to managing the infection and its risk factors 4.
• For the treatment of uncomplicated skin and soft-tissue infections, including those caused by community-acquired meticillin-resistant Staphylococcus aureus (MRSA), minocycline is often preferred over trimethoprim-sulfamethoxazole or doxycycline due to its effectiveness in eradicating the infection 5.
• Cefdinir and cephalexin have been compared for the treatment of mild to moderate uncomplicated skin and skin structure infections, showing similar efficacy but with cefdinir being more highly rated for convenience and having a different adverse event profile 6.
• The choice of antibiotic should consider the potential for resistance, especially in patients with a history of recurrent infections, and the specific pathogens likely involved in the infection 7, 8.

Considerations for Antibiotic Selection

When selecting an oral antibiotic regimen for this patient, considerations should include:

• The effectiveness of the antibiotic against common pathogens causing cellulitis, including MRSA.
• The patient's history of recurrent infections and potential resistance patterns.
• The presence of comorbidities such as PVD and CAD, which may affect the choice of antibiotic due to potential drug interactions or side effects.
• The need for a rigorous approach to managing risk factors and preventing recurrence, as highlighted in the management of recurrent cellulitis 4.