Mastitis Empiric Therapy 

Empiric therapeutic regimens for mastitis are outlined below, including those for nursing mothers, patients with recurrent mastitis, and persons with nonpuerperal mastitis. ^{[1, 2, 3, 4]}

Nursing mothers

Outpatient treatment

Outpatient options includes the following:

• Dicloxacillin 500 mg PO QID for 10-14 days or
• Cephalexin 500 mg PO QID for 10-14 days or
• Amoxicillin-clavulanate 500 mg PO TID or 875 mg PO BID for 10-14 days

If beta-lactam allergy:

• Clarithromycin 500 mg PO BID for 10-14 days (or see following section)

If suspected community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection:

• Clindamycin 300 mg PO TID for 10-14 days or
• Trimethoprim-sulfamethoxazole 1 DS tablet PO BID for 10-14 days ^[4] (caution if nursing preterm infant or child with known or suspected glucose-6-phosphate dehydrogenase [G6PD] deficiency) or 
• Doxycycline 100 mg PO BID for 10-14 days (pregnancy Category D and secreted in breast milk; do not use in pregnancy or if breastfeeding)  

Inpatient treatment

Options includes the following:

• Nafcillin 2 g IV q4h or
• Oxacillin 2 g IV q4h

If beta-lactam allergy or MRSA suspicion:

• Clindamycin 600 mg IV q8h or
• Vancomycin 15 mg/kg IV q12h

For rare strains or refractory cases:

• Linezolid 600 mg PO/IV q12h for 10-14 days (pregnancy category C; unknown if secreted in breast milk) or
• Tigecycline 100-mg IV infusion, then 50-mg IV infusion q12h for 5-14 days​ (pregnancy Category D and unknown if secreted in breast milk; do not use in pregnancy or if breastfeeding) or
• Daptomycin 4 mg/kg IV infusion q24h for 7-14 days (pregnancy category B; secreted in breast milk but poorly bioavailable orally; use caution if breastfeeding)

Emerging treatment options

These drugs have been approved by the FDA for treatment of soft-tissue infections but have not yet been assessed specifically for efficacy in treating breast infections.

• Ceftaroline 600 mg IV q12h; infuse over 5-60 minutes for 5-14 days (approved to treat MRSA infections; pregnancy Category B, unknown if secreted in breast milk) or
• Dalbavancin: (1) 1-dose regimen of 1500 mg IV or (2) 2-dose regimen of 1000 mg IV followed 1 week later by 500 mg IV; infuse IV over 30 minutes (pregnancy category C, unknown if secreted in breast milk) or
• Oritavancin 1-dose regimen of 1200 mg IV infusion over 3 hours (pregnancy category C; unknown if distributed in human breast milk)

When clinical improvement with ceftaroline is apparent, transition the patient to the oral antibiotics listed above for completion of a 10- to 14-day course. ^{[1, 4]}  Further antibiotics may not be required for patients treated with dalbavancin or oritavancin.

If an abscess develops, consider irrigation and debridement along with IV antibiotics.

Patients with recurrent mastitis

Rule out abscess with ultrasonography.

Consider choosing an antibiotic to cover methicillin-resistant Staphylococcus aureus (MRSA): clindamycin, trimethoprim-sulfamethoxazole, or vancomycin. ^[1]

Patients with nonpuerperal mastitis

Consider the possibility of cancer.

A ruptured cyst may be associated with inflammation.

The mastitis may be self-limited, and antibiotics therefore of questionable benefit.

If antibiotic treatment is needed, provide it as for lactating women.