CLOXACILLIN
Indications
- mainly used for the treatment of infections caused by, or suspected of being caused by susceptible, penicillinase - producing staphylococci (eg. cutaneous infections, septicemia, endocarditis and osteomyelitis)
Pharmacology
- cloxacillin is a semisynthetic, penicillinase - resistant penicillin
- penicillinase - resistant penicillins have their greatest in vitro antimicrobial activity against Gram-positive aerobic cocci (S. aureus, S. saprophyticus; groups A, B, C and G streptococci).
- Enterococci, including S. faecalis, are generally resistant
- cloxacillin works like other penicillins: ie. inhibition of bacterial cell wall synthesis
- in healthy, fasting adult volunteers, only 37-60% of an orally administered dose was absorbed; the maximum serum concentration following oral administration in neonates would be expected to occur at about 1 hour
- cloxacillin distributes well into body fluids (synovial fluid, pleural fluid, bile) and tissues (liver, kidneys); however, it penetrates poorly into the CSF
- in adults, approximately 20% of the drug is metabolized in the liver; the remainder of the dose is eliminated as unchanged drug and active metabolites by the kidneys
Side Effects
- hypersensitivity reactions (rash, eosinophilia, hemolytic anemia); these reactions are rare in newborns
- hematological effects (including transient neutropenia, thrombocytopenia)
- gastrointestinal effects (vomiting, diarrhea, gastritis) following oral administration
Dose
- may be given IV or orally
| < 2,000 g | < 7 days
> 7 days | 25 mg/kg q12h
25 mg/kg/q8h |
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| >2,000 g | < 7 days
> 7 days | 25 mg/kg q8h
25 mg/kg q6h |
Supplied
- 50 mg/mL syringe prepared by Pharmacy
- 25 mg/mL oral suspension (after reconstitution); keep refrigerated
- SPECIAL INSTRUCTIONS FOR DILUTION of CLOXACILLIN 500mg (** 500 mg **) vials
- Add 4.8 mL Sterile Water to the 500 mg vial. This provides a concentration of 100 mg/mL.
- Take 5 mL of the 100 mg/mL strength (i.e., 500 mg) and add to 5 mL of diluent. This provides a final concentration of 500 mg/10 mL (= 50 mg/mL) which can then be administered to the baby.
References
- McEvoy G K (ed): AHFS Drug Information, American Society of Hospital Pharmacists, 1991.
- Perlman M and Kirpalani H (eds): Residents Handbook of Neonatology (The Hospital for Sick Children, Toronto, Canada), Mosley Year Book, Toronto, 1992.
- Philip AGS: Neonatology - A Practical Guide, W B Saunders Company, Toronto, 1987.
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