Floxacillin
Floxacillin is a penicillinase-resistant penicillin antibiotic used to treat bacterial infections caused by susceptible gram-positive organisms, particularly penicillin-resistant Staphylococcus aureus. It is commonly prescribed for skin and soft tissue infections, bone and joint infections, and respiratory tract infections where penicillin-resistant staph is suspected.
Floxacillin is a penicillin-type antibiotic used to treat infections caused by penicillin-resistant Staphylococcus bacteria.
Key facts at a glance
- ATC
- J01CF05
- RxNorm
- 4448
- Generic
- Floxacillin
- Class
- atc-j01
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- capsule, suspension, solution
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
8 groupspregnancy
generalno specific adjustment
use only if clearly needed and benefits outweigh potential risks
regular prenatal monitoring
Use with caution and monitor for adverse effects.
lactation
breastfeedingno adjustment needed
compatible with breastfeeding; monitor infant for gastrointestinal disturbances
observe infant for diarrhea, thrush or rash
geriatric
elderlyadjust dose based on renal function
use with caution due to age-related decline in renal function; monitor renal function
regular renal function monitoring
Use with caution and monitor for adverse effects.
pediatric_age
childrendose based on body weight
safe for use in children; typical dose 25-50mg/kg/day in divided doses
standard pediatric monitoring
renal_impairment
mild to moderateno adjustment needed for mild-moderate impairment
monitor renal function; dose reduction may be needed in severe impairment
regular creatinine clearance monitoring
Use with caution and monitor for adverse effects.
renal_impairment
severereduce dose or extend dosing interval
use reduced dose in severe renal impairment; consider therapeutic drug monitoring
close renal function and drug level monitoring
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateno specific adjustment for mild-moderate
use with caution; monitor liver function tests
regular liver function monitoring
Use with caution and monitor for adverse effects.
hepatic_impairment
severeuse lower dose or extended interval
use with caution in severe hepatic impairment; consider dose reduction
frequent liver function tests and clinical monitoring
Use with caution and monitor for adverse effects.
Statistics and clinical data
Drug class
Beta-lactam antibiotics, penicillins with extended spectrum
Mechanism of action
Primary pharmacodynamic action
Common uses
Therapeutic indications
Treatment of infections caused by penicillinase-producing Staphylococcus aureus and other susceptible gram-positive bacteria, including skin and soft tissue infections, wound infections, osteomyelitis, and respiratory tract infections such as pneumonia and bronchitis.
Floxacillin works by inhibiting bacterial cell wall synthesis. It binds to penicillin-binding proteins (PBPs) and blocks the transpeptidation step of peptidoglycan synthesis, weakening the bacterial cell wall and leading to cell death.
Patients with penicillin allergy may react to floxacillin. Common side effects include gastrointestinal symptoms such as nausea, diarrhea, and vomiting. It may reduce the effectiveness of oral contraceptives. Complete the full course as prescribed to prevent antibiotic resistance.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 20, 2026. · Read our editorial policy