UTIMOX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for UTIMOX (UTIMOX).
Amoxicillin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting transpeptidation and autolysin activation. Clavulanate is a beta-lactamase inhibitor that irreversibly binds to and inactivates beta-lactamases, preventing hydrolysis of amoxicillin.
| Metabolism | Amoxicillin is partially metabolized to amoxicilloic acid via renal excretion; Clavulanate is extensively metabolized to 2,5-dihydro-4-(2-hydroxyethyl)-5-oxo-1H-pyrrole-3-carboxylic acid and 1-amino-4-hydroxy-butan-2-one. Both are primarily eliminated renally. |
| Excretion | Primarily renal (85-90% as unchanged drug via glomerular filtration and tubular secretion); biliary/fecal excretion accounts for less than 10%. |
| Half-life | Terminal elimination half-life: 1.0-1.5 hours in adults with normal renal function; prolonged to 3-5 hours in moderate renal impairment (CrCl 30-50 mL/min) and up to 8-12 hours in severe impairment (CrCl <30 mL/min). |
| Protein binding | Approximately 20% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | 0.3-0.4 L/kg; moderate distribution into extracellular fluid, with good penetration into most tissues including bone, synovial fluid, and bile. |
| Bioavailability | Oral: 70-80% (food delays absorption but does not affect extent; avoid high-fat meals). |
| Onset of Action | Oral: 30-60 minutes after oral administration; IV: Immediate (within minutes) upon completion of infusion. |
| Duration of Action | Duration approximately 6-8 hours; dosing interval adjusted to 12-24 hours in renal impairment to maintain therapeutic levels. |
For UTIMOX (amoxicillin/clavulanate), typical adult dose is 875 mg/125 mg orally every 12 hours or 500 mg/125 mg orally every 8 hours, depending on infection severity.
| Dosage form | CAPSULE |
| Renal impairment | For GFR 10-30 mL/min: 500 mg/125 mg every 12 hours. GFR <10 mL/min: 500 mg/125 mg every 24 hours. Hemodialysis: 500 mg/125 mg during dialysis and then every 24 hours. |
| Liver impairment | No specific dose adjustment required for Child-Pugh A or B; caution in severe hepatic impairment (Child-Pugh C) with monitoring for adverse effects. |
| Pediatric use | Weight-based dosing: For children 40 kg or more, use adult dosing; for children <40 kg, 25-45 mg/kg/day of amoxicillin component in divided doses every 12 hours, based on infection severity. Common regimen: 20-40 mg/kg/day amoxicillin in 3 divided doses for more serious infections. |
| Geriatric use | Elderly patients: Normal dosing unless renal impairment; monitor renal function and adjust dose accordingly (per renal adjustment). Increased risk of Clostridioides difficile infection and adverse effects due to age-related renal decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for UTIMOX (UTIMOX).
| Breastfeeding | Amoxicillin is excreted into breast milk in low concentrations (M/P ratio approximately 0.01-0.03). Oral absorption by infants is minimal. No adverse effects reported in nursing infants. Compatible with breastfeeding. |
| Teratogenic Risk | UTIMOX (amoxicillin) is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, and adequate studies in pregnant women have not shown teratogenic effects. However, penicillins cross the placenta. First trimester: No increased risk of major malformations. Second/third trimester: No known fetal harm; used for infections like UTI and GBS prophylaxis. |
■ FDA Black Box Warning
No FDA boxed warning.
| Serious Effects |
History of allergic reaction to penicillins, cephalosporins, or beta-lactam antibiotics; use with caution in patients with severe renal impairment (CrCl <30 mL/min) and hepatic impairment.
| Precautions | Serious hypersensitivity reactions (anaphylaxis), severe cutaneous adverse reactions (SCARs), Clostridioides difficile-associated diarrhea, hepatotoxicity, development of drug-resistant bacteria, use in patients with mononucleosis (risk of rash), renal impairment (dose adjustment), and prolonged therapy may cause bacterial or fungal superinfection. |
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| Fetal Monitoring | Monitor maternal renal function (amoxicillin primarily excreted renally) and signs of allergic reaction. No specific fetal monitoring required. In prolonged therapy, consider monitoring infant for diarrhea or candidiasis. |
| Fertility Effects | No known adverse effects on fertility in animal or human studies. Amoxicillin does not impair reproductive function. |