Moderate (40 to 70%)
See Additional Information


General Information

  • Treatment of MSSA infections
  • Gastrointestinal effects (e.g. diarrhea).
  • Periodic renal, hepatic function, CBC.
  • GI intolerance
  • Allergy (immediate or delayed)
  • Drug fever
  • Cytopenias
  • LFT elevation
  • Interstitial nephritis
  • CNS: seizures (increased risk with higher doses and/or with renal insufficiency)
  • Methotrexate - concomitant use may increase methotrexate serum concentrations and increase the risk of toxicity (e.g. neutropenia).
  • Mycophenolate - may decrease serum concentrations of the active metabolite(s) of Mycophenolate.
  • Tetracyclines may diminish cloxacillin activity.
  • Warfarin - possible increased anticoagulant effect.

Dietary Considerations:

  • Food decreases the extent of absorption of ORAL cloxacillin. Administer ORAL cloxacillin on an empty stomach (1 hour before or 2 hours after meals) to enhance its absorption.

Note: oxacillin/cloxacillin and cefazolin/cephalexin equivalent spectrum of activity for gram positive organisms.


  • PO: $0.48/Dose; $9.60/5 Days
  • IV: $4.35/Dose; $87.00/5 Days

Antimicrobial class: Antistaphylococcal Penicillin

Pregnancy category: B

Average serum half life: 0.5 - 1 hour

Urine penetration: Therapeutic

Lung penetration: Therapeutic

Biliary penetration: Moderate

CSF penetration: Good