CEFIZOX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CEFIZOX (CEFIZOX).
Cefizox (ceftizoxime) is a third-generation cephalosporin that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), thereby inhibiting transpeptidation and autolysin inhibition.
| Metabolism | Ceftizoxime is not significantly metabolized; it is primarily excreted unchanged in the urine via glomerular filtration and tubular secretion. |
| Excretion | Primarily renal (90-95% unchanged via glomerular filtration and tubular secretion); biliary (<1%); fecal (minimal) |
| Half-life | 1.7-1.9 hours in adults; prolonged to 15-25 hours in severe renal impairment (CrCl <10 mL/min) |
| Protein binding | 85-95%, primarily to albumin |
| Volume of Distribution | 0.2-0.4 L/kg; low Vd indicates limited extravascular distribution, primarily in extracellular fluid |
| Bioavailability | IM: 100% (complete absorption) |
| Onset of Action | IV: immediate; IM: 30-60 minutes to therapeutic serum concentrations |
| Duration of Action | 6-8 hours in normal renal function; extended to 12-24 hours in renal impairment due to delayed clearance |
| Action Class | Cephalosporins: 3 generation |
| Brand Substitutes | Unizox 250mg Injection, Eldcef 250mg Injection, Prozoxime 250mg Injection |
1-2 g IV/IM every 8-12 hours; maximum 12 g/day for severe infections.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl 50-79 mL/min: 1-2 g every 8-12 hours; CrCl 30-49 mL/min: 1-2 g every 12 hours; CrCl 10-29 mL/min: 1-2 g every 24 hours; CrCl <10 mL/min: 1-2 g every 48 hours. |
| Liver impairment | No dose adjustment required for mild to moderate hepatic impairment; no data for severe impairment. |
| Pediatric use | Infants and children: 50-100 mg/kg/day IV/IM divided every 6-8 hours; severe infections: up to 150 mg/kg/day. |
| Geriatric use | No specific adjustment except based on renal function; monitor renal status. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CEFIZOX (CEFIZOX).
| Breastfeeding | Excreted in breast milk in low concentrations; M/P ratio 0.1-0.4. Considered compatible with breastfeeding due to low oral bioavailability in infants. Monitor infant for diarrhea and rash. |
| Teratogenic Risk | No evidence of teratogenicity in animal studies; human data limited. FDA Pregnancy Category B. Crosses placenta but no known fetal harm in first trimester. Risk of diarrhea and candidiasis in neonates if used near term. |
| Fetal Monitoring |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to ceftizoxime or other cephalosporins","History of anaphylactic reaction to penicillins or other beta-lactams (cross-sensitivity)"]
| Precautions | ["Hypersensitivity reactions (including anaphylaxis)","Clostridium difficile-associated diarrhea (CDAD)","Superinfection","Drug-induced hemolytic anemia","Renal impairment (dose adjustment required)","Seizure risk with high doses","Potential for vitamin K deficiency"] |
| Food/Dietary | No significant food interactions have been reported. Cefizox is administered parenterally, so oral intake does not affect absorption. However, alcohol consumption should be avoided during treatment and for 72 hours after the last dose, as cephalosporins may cause a disulfiram-like reaction, including nausea, vomiting, flushing, and headache. |
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| For prolonged therapy: monitor maternal CBC, renal function, and hepatic enzymes. In neonates: observe for superinfection (oral thrush, diaper rash) and diarrhea. |
| Fertility Effects | No known adverse effects on fertility in animal studies. No human data available. |
| Clinical Pearls | Cefizox (ceftizoxime) is a third-generation cephalosporin with broad-spectrum activity against gram-negative and gram-positive organisms, including Bacteroides fragilis. It is particularly useful in intra-abdominal, gynecologic, and respiratory infections due to its stability against beta-lactamases. It has poor oral bioavailability and must be administered parenterally. Dosage adjustment is required in renal impairment (CrCl <50 mL/min). Cross-allergenicity with penicillins exists in about 10% of patients. Monitor for superinfection with prolonged use. |
| Patient Advice | Take this medication exactly as prescribed by your healthcare provider. It is given as an injection into a muscle or vein, typically by a healthcare professional. · Inform your doctor if you have a history of allergic reactions to penicillins, cephalosporins, or other beta-lactam antibiotics. · Report any signs of allergic reaction, such as rash, itching, swelling, or difficulty breathing, immediately. · If you have kidney disease, your doctor may need to adjust your dose; provide a full medical history. · Notify your doctor if you experience severe diarrhea, as this may indicate Clostridioides difficile infection. · Cefizox may cause false-positive results in urine glucose tests; use glucose oxidase-based tests instead. |