POLYMOX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for POLYMOX (POLYMOX).
Amoxicillin is a bactericidal antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs) and inhibiting transpeptidase activity, leading to cell lysis.
| Metabolism | Amoxicillin is primarily metabolized by hydrolysis of the beta-lactam ring to inactive metabolites. It is partially metabolized by hepatic enzymes, but the exact pathways are not well defined. |
| Excretion | Renal (70-80% unchanged via tubular secretion and glomerular filtration); biliary/fecal (small amount, <5%) |
| Half-life | Terminal elimination half-life = 1-1.5 hours in adults; prolonged in renal impairment (up to 12-20 hours in anuria) |
| Protein binding | ~20% bound to serum albumin |
| Volume of Distribution | 0.3-0.4 L/kg; indicates distribution primarily into extracellular fluid |
| Bioavailability | Oral: 50-70% (decreased by food); IM: ~100% |
| Onset of Action | Oral: 30-60 minutes; IV/IM: immediate (within minutes) |
| Duration of Action | 6-8 hours (oral); 4-6 hours (IV/IM); short half-life necessitates frequent dosing |
| Molecular Weight | 419.45 |
| Brand Substitutes | Moxiken CL 250 mg/250 mg Capsule, Lariclox 250mg/250mg Capsule, Stamox 250 mg/250 mg Capsule, Kokkos 250mg/250mg Capsule, Nemoclox 250 mg/250 mg Capsule |
250-500 mg orally every 8 hours or 500-875 mg orally every 12 hours; maximum 4 g/day.
| Dosage form | FOR SUSPENSION |
| Renal impairment | CrCl >30 mL/min: no adjustment; CrCl 10-30 mL/min: 250-500 mg every 12 hours; CrCl <10 mL/min: 250-500 mg every 24 hours. |
| Liver impairment | No dose adjustment required for mild to moderate hepatic impairment; Child-Pugh C: consider dose reduction or increased dosing interval (specific recommendations not established). |
| Pediatric use | Neonates and infants <3 months: 30 mg/kg/day divided every 12 hours; Children ≥3 months and <40 kg: 25-50 mg/kg/day divided every 8 hours or 45-90 mg/kg/day divided every 12 hours; maximum 2-3 g/day. |
| Geriatric use | No specific dose adjustment; monitor renal function and adjust according to creatinine clearance; increased risk of adverse effects due to age-related renal decline. |
| 1st trimester | Category B: No evidence of risk in humans. Animal studies show no fetal harm. |
| 2nd trimester | Category B: Safe to use based on human data. |
| 3rd trimester | Category B: Safe to use, but consider theoretical risk of kernicterus in neonates if high doses near term. |
Clinical note
Comprehensive clinical and safety monograph for POLYMOX (POLYMOX).
| Placental transfer | Crosses placenta in small amounts; considered safe. |
| Breastfeeding | Compatible with breastfeeding. Excreted in breast milk in low amounts. Monitor infant for diarrhea or rash. |
| Lactation Rating | L1 |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Hypersensitivity to penicillinsHistory of anaphylactic reaction to beta-lactam antibiotics
| Precautions | Serious hypersensitivity reactions (anaphylaxis) may occur, Clostridium difficile-associated diarrhea (CDAD) can occur, Development of drug-resistant bacteria, Use with caution in patients with mononucleosis due to high incidence of maculopapular rash, Renal impairment may require dose adjustment |
| Food/Dietary | No significant food interactions. However, taking with food can reduce gastrointestinal upset. Avoid acidic beverages (e.g., fruit juice, soda) close to dosing as they may degrade the drug in the stomach. |
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| Teratogenic Risk | Polymox (amoxicillin) is classified as FDA Pregnancy Category B. No evidence of teratogenicity in animal studies. Limited human data show no increased risk of major birth defects. First trimester: no documented risk; second and third trimesters: considered safe when indicated. However, theoretical risk of altered gut flora in neonate if administered near term. |
| Fetal Monitoring | No specific fetal monitoring required. For prolonged therapy, consider maternal monitoring for signs of superinfection, gastrointestinal adverse effects, or allergic reactions. In neonates, observe for rash, diarrhea, or signs of hypersensitivity. |
| Fertility Effects | No known adverse effects on human fertility. In animal studies, no impairment of fertility or reproductive performance at therapeutic doses. |
| Clinical Pearls |
| Polymox (amoxicillin) is a broad-spectrum penicillin antibiotic. For Group A streptococcal pharyngitis, a 10-day course is required to prevent rheumatic fever. Take with food to reduce GI upset. Adjust dose in renal impairment (CrCl <30 mL/min). Monitor for rash, especially in patients with mononucleosis or concurrent allopurinol use. Do not use in penicillin-allergic patients. |
| Patient Advice | Take exactly as prescribed, even if you feel better. · Complete the full course of therapy. · Take with a full glass of water; may be taken with or without food. · Report any rash, diarrhea, or signs of allergic reaction. · Avoid taking with antacids or laxatives; separate by 2 hours. · Store at room temperature, away from moisture and heat. · Do not share this medication with others. |