Section 1.1

Midwives may independently prescribe, order and administer this drug.

Cloxacillin is a penicillin-type antibiotic and is closely related to methicilin. Interferes with bacteria cell wall formation by weakening the cell wall, causing rupture and killing bacteria.

Indications and Clinical Use:

Mastitis as a complication of lactation. It is also used in other skin and soft tissue infections which are not in the Midwives Regulation – Schedule A and B.

Cloxacillin is particularly effective in Staph Aureus infections, and covers about 79% of those bacteria. The remainder (about 21%) are “methicillin resistant staph aureus” MRSA, which may be susceptible to clindamycin.

It is generally not used to treat streptococcal infections as there are other more specific choices, or UTIs as it has limited gram negative coverage.


Hypersensitivity to Cloxacillin. Any other penicillin allergy.

Warnings and Precautions:

Prolonged use may result in fungal or bacterial superinfection, including C. difficile-associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months post-antibiotic treatment.

Use with caution in patients with renal impairment; modify dosage in severe impairment.
Breastfed infants may develop slightly looser stools than normal.


No (Limited) Human Data – Probably Compatible


Category L2 – Limited Data – Probably Compatible

Adverse Reactions:

Upset stomach, diarrhea, vomiting, vaginal infection and mild skin rash.

The following side effects should be reported to a medical practitioner immediately: severe skin rash, itching, hives, difficulty breathing or swallowing, wheezing, unusual bleeding or bruising, sore throat, painful mouth or throat sores, jaundice and diarrhea.

Dosage and Administration:

Cloxacillin: 500 mg orally every 6 hours for 10-14 days.
Cloxacillin should be taken 1 hour before or 2 hours after meals with water. Serum levels are reduced by 50% with food intake.
Taking an active probiotic concurrently may help minimize changes to GI flora

Onset of Action:

Rapid onset, peak in about 1 hour.


Adults: 0.5-1.5 hours