FORBAXIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FORBAXIN (FORBAXIN).
FORBAXIN is a prodrug of the active moiety cefditoren, a cephalosporin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis and death.
| Metabolism | Cefditoren pivoxil is hydrolyzed by esterases to cefditoren, which is minimally metabolized. The prodrug is not significantly metabolized by CYP450 enzymes. |
| Excretion | Renal (60-70% unchanged), biliary/fecal (20-30%) |
| Half-life | 8-12 hours; prolonged in renal impairment (up to 24 hours in severe cases) |
| Protein binding | 30-40% bound to albumin |
| Volume of Distribution | 0.6-0.8 L/kg; indicates moderate tissue penetration |
| Bioavailability | Oral: 60-70%; Intravenous: 100% |
| Onset of Action | Intravenous: 15-30 minutes; Oral: 1-2 hours |
| Duration of Action | 12-24 hours; may be extended in hepatic impairment |
| Molecular Weight | 307.3 |
IV: 500 mg every 12 hours, infused over 30 minutes.
| Dosage form | TABLET |
| Renal impairment | CrCl 30-49 mL/min: 250 mg every 12 hours; CrCl 15-29 mL/min: 250 mg every 24 hours; CrCl <15 mL/min: 250 mg every 48 hours; hemodialysis: administer after dialysis. |
| Liver impairment | Child-Pugh A and B: no adjustment required; Child-Pugh C: not recommended, use alternative agent. |
| Pediatric use | Weight ≥40 kg: 500 mg IV every 12 hours; Weight <40 kg: 10 mg/kg IV every 12 hours, max 500 mg per dose. |
| Geriatric use | No specific dose adjustment based on age; adjust for renal function per renal_adjustment criteria. |
| 1st trimester | Avoid during first trimester unless essential; animal studies show embryotoxicity. |
| 2nd trimester | Use only if benefit outweighs risk; limited human data. |
| 3rd trimester | Risk of kernicterus in neonates; avoid near term. |
Clinical note
Comprehensive clinical and safety monograph for FORBAXIN (FORBAXIN).
| Placental transfer | Crosses placenta; reaches therapeutic concentrations in fetal circulation. |
| Breastfeeding | Excreted into breast milk; potential for infant jaundice and kernicterus; use with caution. |
| Lactation Rating | L3 (Moderately Safe) |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Hypersensitivity to FORBAXINSevere hepatic impairmentGlucose-6-phosphate dehydrogenase deficiencyPregnancy near term
| Precautions | Clostridium difficile-associated diarrhea, Hypersensitivity reactions including anaphylaxis, Seizures in patients with renal impairment, Potential for development of drug-resistant bacteria, Pseudomembranous colitis |
| Food/Dietary | Avoid concurrent intake of calcium-rich foods (e.g., dairy products) or supplements as they may reduce absorption. Administer on an empty stomach, at least 2-3 hours before or after meals. |
| Clinical Pearls |
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| Teratogenic Risk | FORBAXIN is contraindicated in pregnancy. Teratogenic effects have been observed in animal studies, including skeletal and visceral malformations. First trimester exposure carries the highest risk for major congenital anomalies. Second and third trimester exposure may cause fetal renal impairment and oligohydramnios. |
| Fetal Monitoring | Monitor maternal renal function and electrolytes. If inadvertent exposure occurs during pregnancy, perform detailed fetal ultrasound to assess for anomalies and monitor amniotic fluid volume. |
| Fertility Effects | FORBAXIN has been shown to impair fertility in animal studies with reduced implantation rates and sperm motility. In humans, reversible decreases in fertility may occur; consider fertility preservation prior to treatment. |
| FORBAXIN (fosfomycin tromethamine) is a broad-spectrum antibiotic primarily used for uncomplicated urinary tract infections (UTIs). It achieves high urinary concentrations and is effective even against multidrug-resistant organisms. Administer on an empty stomach for optimal absorption. Avoid use in patients with severe renal impairment (CrCl <10 mL/min). Monitor for hypersensitivity reactions and Clostridioides difficile-associated diarrhea. |
| Patient Advice | Take this medication exactly as prescribed, usually as a single dose. · Dissolve the powder in water and drink immediately. Do not take in dry form. · Take on an empty stomach, at least 2-3 hours before or after a meal. · Complete the full course even if symptoms improve. · Contact your healthcare provider if symptoms persist beyond 48 hours or if you develop severe diarrhea, rash, or signs of an allergic reaction. · Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding. · Avoid driving or operating machinery if you experience dizziness or drowsiness. |