What oral antibiotics can be used for a patient with a skin infection who did not respond to triple antibiotic (topical antibiotic) ointment?

From the Guidelines

For a patient with a skin infection not responding to topical triple antibiotic ointment, oral antibiotics such as clindamycin (300-450 mg three times daily for 7-10 days) or trimethoprim-sulfamethoxazole (1-2 DS tablets twice daily) are appropriate options, as they provide coverage for common skin pathogens like Staphylococcus aureus and Streptococcus species, including MRSA. The choice of antibiotic depends on the severity of the infection, patient allergies, and local resistance patterns 1.

Key Considerations

• The patient's infection severity, allergies, and local resistance patterns should guide the selection of oral antibiotics.
• Clindamycin and trimethoprim-sulfamethoxazole are effective against MRSA, a common cause of skin infections.
• Patients should complete the full course of antibiotics, even if symptoms improve quickly, and stay hydrated to support the healing process.
• It is essential to monitor for worsening symptoms, fever, or spreading redness, which may indicate the need for alternative treatments or further evaluation.

Antibiotic Options

• Clindamycin: 300-450 mg three times daily for 7-10 days
• Trimethoprim-sulfamethoxazole: 1-2 DS tablets twice daily for 7-10 days
• Doxycycline: 100 mg twice daily for 7-10 days, although its use is limited in children under 8 years old 1
• Linezolid: 600 mg twice daily for 7-10 days, although it is more expensive compared to other alternatives 1

Important Notes

• The use of rifampin as a single agent or as adjunctive therapy for the treatment of skin and soft tissue infections is not recommended due to the risk of resistance development 1.
• Patients with severe or extensive disease, systemic illness, or immunosuppression may require hospitalization and broader-spectrum antibiotics, including vancomycin, linezolid, or daptomycin 1.

From the FDA Drug Label

For the following infections, a dosage of 500 mg may be administered every 12 hours: streptococcal pharyngitis, skin and skin structure infections, and uncomplicated cystitis in patients over 15 years of age. The usual adult dose is 250 mg every 6 hours For more severe infections or those caused by less susceptible organisms, larger doses may be needed In severe infections, the dosage may be doubled.

For a patient with a skin infection who did not respond to triple antibiotic ointment, oral antibiotics such as cephalexin (PO) can be used. The dosage for skin and skin structure infections is 500 mg every 12 hours or 250 mg every 6 hours.

• Key considerations:
  • The dosage may need to be adjusted based on the severity of the infection and the patient's response to treatment.
  • In severe infections, the dosage may be doubled.
  • It is essential to follow the recommended dosage and administration instructions to ensure effective treatment and minimize the risk of adverse effects.
  • The treatment should be continued for at least 48 hours after the patient has become afebrile, asymptomatic, and cultures are negative.
  • Bacteriologic studies should be performed to determine the causative organisms and their susceptibility to cephalexin. 2

From the Research

Oral Antibiotics for Skin Infections

If a patient did not respond to triple antibiotic ointment, several oral antibiotics can be considered for the treatment of skin infections.

• Cephalexin is an effective option for streptococcal and staphylococcal skin infections, with cure rates of 90% or higher 3.
• Dicloxacillin is another option, which has been shown to be equally effective as cephalexin in treating staphylococcal skin infections 4.
• Clindamycin and erythromycin are also alternatives for less serious methicillin-susceptible S. aureus (MSSA) infections, such as skin and soft tissue infections 5.
• For community-acquired methicillin-resistant S. aureus (MRSA) infections, lincosamides (clindamycin, lincomycin) or cotrimoxazole may be considered 5.

Considerations for Antibiotic Choice

When choosing an oral antibiotic, factors such as cost, palatability, and adverse reactions should be considered 3.

• Cephalexin has been shown to have a favorable safety profile and is well-tolerated, even in young children 3.
• The choice of antibiotic may also depend on the specific type of infection and the presence of any underlying conditions, such as penicillin hypersensitivity 5.

Comparison of Oral and Topical Antibiotics

Oral antibiotics, such as cephalexin, have been compared to topical antibiotics, such as retapamulin ointment, in the treatment of secondarily infected traumatic lesions of the skin 6.

• Both oral and topical antibiotics have been shown to be effective in treating skin infections, but the choice of treatment may depend on the specific circumstances and patient preferences 6.