Mastitis Empiric Therapy

Updated: Mar 12, 2019
Author: Andrew C Miller, MD, FACEP, FAIM, Dip ABIM; Chief Editor: Thomas E Herchline, MD 

Empiric Therapy Regimens

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, 5, 6, 7, 8]

Outpatient treatment

Routine cases:

If penicillin intolerance (not allergy):

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, secreted in breast milk; do not use in pregnancy or if breastfeeding ) or
  • Ciprofloxacin 500 mg PO BID for 10-14 days (pregnancy Category C, secreted in breast milk, use caution if pregnant or breastfeeding)

Inpatient treatment

Routine cases:

  • Nafcillin 2 g IV q4h for 10-14 days; infuse over 30-60 minutes or
  • Oxacillin 2 g IV q4h for 10-14 days; infuse over 30 minutes

If beta-lactam allergy or MRSA suspicion:

  • Clindamycin 600 mg IV q8h; infuse over 10-60 minutes, maximum 30 mg/min for 10-14 days or
  • Vancomycin 15 mg/kg IV q12h, targeting trough levels between 10-15 mcg/mL or 15-20 mcg/mL if documented MRSA; infusion not to exceed >1 g/hour

For rare/resistant strains (eg, VRE, MRSA) or refractory cases:

  • Linezolid 600 mg PO/IV q12h for 10-14 days; infuse over 30-120 minutes (pregnancy category C; secreted in breast milk, caution if used while breastfeeding) or
  • Tigecycline 100-mg IV infusion, then 50-mg IV infusion q12h for 5-14 days; infuse over 30-60 minutes​ (pregnancy Category D and suspected to be secreted in breast milk; do not use in pregnancy or if breastfeeding ) or
  • Daptomycin 4 mg/kg IV infusion q24h for 7-14 days; infuse over 30 minutes (pregnancy category B; secreted in breast milk in low concentrations, although it has poor oral bioavailability; 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 for 5-14 days; infuse over 5-60 minutes (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 over 30 minutes (pregnancy category C, unknown if secreted in breast milk; further antibiotics may not be required ) or  ​
  • Oritavancin 1-dose regimen of 1200 mg IV infusion over 3 hours (pregnancy category C; unknown if distributed in human breast milk; further antibiotics may not be required ) or​
  • Delafloxacin 450 mg PO q12h for 10-14 days or 300 mg IV q12h for 10-14 days; infuse over 60 minutes (no pregnancy classification, unknown if secreted in breast milk, use caution if pregnant or breastfeeding) [9, 10]
  • Nisin (still experimental) [8]

Fungal mastitis

Fungal mastitis should be suspected when pain is out of proportion to clinical findings. Pain is often described as “shooting from nipple through the breast to the chest wall.” Concurrent yeast infections are also common, such as oral thrush or diaper dermatitis. Evidence regarding treatment is conflicting.[7]

Mild infections are treated as follows:

  • Nystatin topical applied to affected area q8-12hr for 2 weeks (pregnancy category B, no lactation information) or
  • Miconazole topical applied to affected area BID for 2 weeks (pregnancy category C, no lactation information) or
  • Ketoconazole topical applied to affected area once daily for 2 weeks (pregnancy category C, no lactation information)

Moderate-to-severe infections are treated as follows:

  • Fluconazole 400 mg IV/PO (initial dose), followed by 200 mg daily, for a minimum of 10 days. Single large doses are ineffective. The infant is not adequately treated with the amount of fluconazole that is passed via breast milk and therefore should be treated independently with 6-12 mg/kg initial dose, followed by 3-6 mg/kg/day for a minimum of 10 days.

Recurrent mastitis

See the list below:

  • Rule out abscess with ultrasonography.
  • Consider choosing an antibiotic to cover MRSA. [1]
  • If an abscess develops, consider irrigation and debridement along with IV antibiotics.

Nonpuerperal mastitis

See the list below:

  • Consider malignancy.
  • A ruptured cyst may be associated with inflammation.
  • Mastitis may be self-limited, with antibiotics being of limited benefit.
  • If antibiotic treatment is needed, prescribe similarly to lactating patients.
  • Central/subareolar infections usually result from ductal infection by anaerobic bacteria.
  • Consider amoxicillin/clavulanate 875 mg PO BID or clarithromycin 500 mg PO BID plus  metronidazole 500 mg PO TID. [5]