What antibiotic is recommended for mastitis in breastfeeding women?

Antibiotic for Mastitis in Breastfeeding

For lactational mastitis requiring antibiotics, use cephalexin 500 mg orally four times daily or dicloxacillin 500 mg orally four times daily as first-line therapy, both of which are safe during breastfeeding and effective against Staphylococcus aureus, the most common causative organism. 1

First-Line Antibiotic Selection

Cephalexin (first-generation cephalosporin) is the preferred first-line agent:

• Dosing: 500 mg orally four times daily 1
• Safe during breastfeeding with minimal transfer to breast milk 1, 2
• Effective against methicillin-susceptible S. aureus, which causes the majority of infectious mastitis cases 1, 3

Dicloxacillin is an equally effective alternative:

• Dosing: 500 mg orally every 6 hours 1, 4
• Extremely low transfer into breast milk with a relative infant dose of only 0.03% 4
• High plasma protein binding results in poor penetration into breast milk 4
• Particularly effective for methicillin-susceptible S. aureus 1

When to Initiate Antibiotics

Conservative management should be attempted first for 1-2 days before starting antibiotics, as most mastitis cases are inflammatory rather than infectious 5:

• Use NSAIDs for pain and inflammation 5
• Apply ice to the affected breast 5
• Continue direct breastfeeding from the affected breast 5
• Minimize pumping (avoid overstimulation) 5

Start antibiotics if:

• No improvement after 24-48 hours of conservative measures 5
• Symptoms worsen 5
• Fever persists or worsens 3, 5

Alternative Antibiotics for Special Circumstances

For penicillin-allergic patients:

• Erythromycin or azithromycin are acceptable alternatives 1, 2
• Important caveat: Very low risk of infantile hypertrophic pyloric stenosis if macrolides are used during the first 13 days of the infant's life 1, 2
• Generally considered safe after this 13-day period 1

For suspected or confirmed MRSA:

• Consider clindamycin if local MRSA prevalence is high, previous MRSA infection exists, or no response to first-line therapy 1
• Use with caution: May increase GI side effects (diarrhea) in the infant 6, 1
• MRSA coverage should be considered if symptoms fail to improve on standard therapy 1

Amoxicillin/clavulanic acid is a broad-spectrum alternative:

• Safe during breastfeeding based on limited human data 1, 7
• Useful when broader coverage is needed 1

Critical Management Principles

Continue breastfeeding throughout treatment:

• Continued breastfeeding is essential for mastitis resolution and does not pose risk to the infant 1, 3
• Regular breast emptying through direct breastfeeding prevents complications 1, 2
• Approximately 10% of mastitis cases progress to breast abscess if not properly treated 1, 3
• Breastfeeding should continue even on the affected breast unless the infant's mouth would contact purulent drainage from an abscess 2

Monitoring and follow-up:

• If symptoms worsen or do not improve within 48-72 hours of starting antibiotics, reevaluate to rule out abscess 1
• Consider obtaining milk cultures to guide antibiotic therapy, especially in recurrent or severe cases 5
• Perform ultrasonography if immunocompromised or symptoms are worsening/recurrent 5

Common Pitfalls to Avoid

Do NOT recommend these outdated practices:

• Excessive pumping to "empty the breast" (worsens inflammation) 5
• Heat application (may worsen condition) 5
• Aggressive breast massage (causes tissue trauma and increases risk) 5
• Stopping breastfeeding due to antibiotic concerns (causes more harm including engorgement, blocked ducts, and loss of breastfeeding benefits) 2

Avoid these antibiotics during breastfeeding:

• Doxycycline and tetracyclines (impact infant development) 1
• Fluoroquinolones as first-line (theoretical cartilage damage concerns in infants) 2