Flucloxacillin
J01C - Beta-lactam antibacterials, penicillins
ATC J01CF05
Small molecule
🧬 Cross-allergy: Penicillins
JFDA label: Floxapen Caps.
Mechanism of Action
Inhibitor of Bacterial penicillin-binding protein — Bacterial penicillin-binding protein inhibitor
| Target | Action | Gene / class |
|---|---|---|
| Bacterial penicillin-binding protein efficacy | INHIBITOR |
Indications
Approved
- Bacterial Infections — bacterial disease
Off-label
- Cellulitis
- Osteomyelitis
- Skin Diseases
- Staphylococcal Infections
Class profile
| gramStatus | Gram+ |
|---|---|
| spectrumBreadth | Narrow |
| atypicalCoverage | No |
| isBactericidal | 1 |
| moaCategory | Cell wall synthesis inhibitor (beta-lactam, penicillinase-stable) |
| pdIndex | Time-dependent |
| postAntibioticEffect | None |
| mrsaCoverage | 0 |
| resistanceMechanisms | PBP2a mutation (mecA gene) |
Pregnancy & Lactation
Pregnancy
Lactation
Probably Compatible
Hale L2
It is acceptable to use during breastfeeding and is frequently used abroad to treat mastitis in nursing mothers.[ 1 - 3 ] Limited information indicates that floxacillin levels in milk are low and are not expected to cause adverse
Monitoring
| Efficacy | Culture and susceptibility testing; clinical resolution (temperature, WBC, CRP, procalcitonin) |
|---|---|
| Toxicity | Renal function (dose adjustment in renal impairment); hepatic function for hepatically cleared agents; signs of C. difficile infection (diarrhoea) |
| Clinical pearl | Culture results guide de-escalation to narrower-spectrum therapy. Review antibiotic appropriateness at 48–72 h (antimicrobial stewardship). |
| Counseling | Complete the full course. Report persistent diarrhoea, rash, or lack of improvement after 48–72 h. |
Chemistry & Properties
| Formula | C19H17ClFN3O5S |
|---|---|
| Molecular weight | 453.88 g/mol |
| IUPAC name | (2S,5R,6R)-6-[[3-(2-chloro-6-fluorophenyl)-5-methyl-1,2-oxazole-4-carbonyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid |
| CAS | 5250-39-5 |
| PubChem CID | 21319 |
| InChIKey | UIOFUWFRIANQPC-JKIFEVAISA-N |
| logP | 2.69 (XLogP 2.6) |
| Polar surface area | 112.74 Ų |
| H-bond acceptors / donors | 6 / 2 |
| Drug-likeness (QED) | 0.68 |
| Lipinski violations | 0 |
SMILES
Cc1onc(-c2c(F)cccc2Cl)c1C(=O)N[C@@H]1C(=O)N2[C@@H]1SC(C)(C)[C@@H]2C(=O)OBiology & Pharmacokinetics
Pharmacokinetics
| BBB penetrant | No |
|---|
Enzyme interactions
| Enzyme | Role | Detail |
|---|---|---|
| CYP1A2 | Substrate | — |
| CYP2C19 | Substrate | — |
Transporters
BCRP (Inhibitor)BCRP (Inhibitor)BSEP (Inhibitor)BSEP (Inhibitor)MRP1 (Inhibitor)MRP2 (Inhibitor)OATP1B1 (Inhibitor)OATP1B3 (Inhibitor)P-gp (Inhibitor)PEPT1 (Inhibitor)BCRP (Substrate)P-gp (Substrate)
Registered Products (4)
| Brand | Form / strength | Pack | Agent | Citizen (JOD) |
|---|---|---|---|---|
| Flumox 250mg Dry Susp | Suspension (as Trihydrate) 125 mg/5 ml, (as Monohydrate) 125 mg/5 ml | 100 ml | AL-Faiasel Drug Store | 2.080 |
| Floxapen Caps. | Capsule 250 mg | 20 cap | Suleiman Tannous & Sons Co. Ltd | 2.140 |
| Flumox | Capsule 250 mg, 250 mg | 16 cap | AL-Faiasel Drug Store | 3.640 |
| Floxapen Suspension | Suspension 125 mg/5 ml | 100 ml | Suleiman Tannous & Sons Co. Ltd | 3.670 |