AMOXICILLIN PEDIATRIC
Clinical safety rating: safe
Probenecid decreases renal tubular secretion of amoxicillin May reduce efficacy of oral contraceptives Serious and occasionally fatal hypersensitivity reactions have been reported.
Amoxicillin is a semisynthetic penicillin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). It blocks the transpeptidation step in peptidoglycan cross-linking, leading to cell lysis and death.
| Metabolism | Amoxicillin is primarily metabolized by hydrolysis to penicilloic acid, which is then excreted renally. It does not undergo extensive hepatic metabolism; renal clearance involves tubular secretion and glomerular filtration. |
| Excretion | Renal: 60-80% unchanged via glomerular filtration and tubular secretion; biliary: minor (<10%); fecal: <5%. |
| Half-life | Terminal elimination half-life: 1-1.5 hours in children with normal renal function; prolonged to 7-21 hours in anuria. |
| Protein binding | 17-20% bound to serum proteins, primarily albumin. |
| Volume of Distribution | 0.3-0.5 L/kg; reflects distribution into extracellular fluid and well-perfused tissues; crosses placenta and distributes into pleural, synovial, and peritoneal fluids. |
| Bioavailability | Oral: 75-90% (absorption is rapid but incomplete; food does not significantly affect absorption). |
| Onset of Action | Oral: 1-2 hours (absorption and distribution); IV: immediate (peak effect within 15-30 minutes). |
| Duration of Action | 6-8 hours for susceptible organisms; shorter for highly sensitive pathogens. Clinical effect persists for 4-6 times the half-life (approximately 6-9 hours). |
250-500 mg orally every 8 hours or 500-875 mg orally every 12 hours for adults.
| Dosage form | FOR SUSPENSION |
| Renal impairment | CrCl 10-30 mL/min: administer every 12 hours. CrCl <10 mL/min: administer every 24 hours. Hemodialysis: administer dose after dialysis. |
| Liver impairment | No specific dose adjustment required for Child-Pugh A or B. Child-Pugh C: consider dose reduction based on clinical response. |
| Pediatric use | Neonates <4 weeks: 30 mg/kg/day divided every 12 hours. Infants and children >4 weeks: 20-50 mg/kg/day divided every 8 hours (mild-moderate infection) up to 80-100 mg/kg/day divided every 6-8 hours (severe infection). |
| Geriatric use | No specific dose adjustment based solely on age; assess renal function and adjust accordingly due to age-related decline in GFR. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Probenecid decreases renal tubular secretion of amoxicillin May reduce efficacy of oral contraceptives Serious and occasionally fatal hypersensitivity reactions have been reported.
| FDA category | Human |
| Breastfeeding | Amoxicillin is excreted into breast milk in low concentrations (M/P ratio approximately 0.01-0.02). Considered compatible with breastfeeding; minimal risk of infant effects such as diarrhea or allergic sensitization. Monitor infant for potential gastrointestinal disturbances. |
| Teratogenic Risk |
■ FDA Black Box Warning
No FDA black box warning.
| Common Effects | Diarrhea |
| Serious Effects |
Hypersensitivity to amoxicillin or any penicillin derivative; history of anaphylactic reaction to beta-lactams.
| Precautions | Serious hypersensitivity reactions (anaphylaxis) may occur; discontinue therapy if allergic reaction occurs. Clostridium difficile-associated diarrhea (CDAD) can occur. Adjust dose in renal impairment. Use caution in patients with mononucleosis due to high incidence of morbilliform rash. Prolonged use may result in superinfection. |
| Food/Dietary | Amoxicillin absorption is not significantly affected by food; may be taken with or without meals. However, to minimize gastrointestinal upset, administer with a small amount of food if needed. Avoid acidic beverages (e.g., fruit juices) within 1 hour of dosing as they may degrade the antibiotic. |
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| Amoxicillin is classified as FDA Pregnancy Category B. No evidence of teratogenicity in animal studies. Human data from pregnant women indicate no increased risk of major birth defects across all trimesters. Caution in first trimester due to limited data, but generally considered safe. |
| Fetal Monitoring | Standard prenatal care; no specific monitoring required beyond routine. Monitor for hypersensitivity reactions (rash, anaphylaxis) and gastrointestinal adverse effects. In prolonged therapy, monitor maternal renal and hepatic function. |
| Fertility Effects | No known adverse effects on fertility in animal or human studies. Amoxicillin does not impair reproductive function. |
| Clinical Pearls | Amoxicillin pediatric suspension is dosed based on body weight; typical dose is 20-40 mg/kg/day in divided doses every 8 hours. For high-dose therapy (e.g., resistant pneumococcus), 80-90 mg/kg/day in two divided doses. Shake suspension well before each dose. Use within 14 days after reconstitution; discard unused portion. Not for patients with severe renal impairment (CrCl <30 mL/min) without dose adjustment. Monitor for rash, diarrhea, and hypersensitivity reactions. |
| Patient Advice | Take this medication exactly as prescribed; complete the full course even if your child feels better. · Shake the bottle well before each dose; measure the dose with the provided dosing device. · Refrigerate the suspension after mixing; do not freeze. Discard any unused portion after 14 days. · Do not give this medication if your child is allergic to penicillins or cephalosporins. · Common side effects include diarrhea, nausea, and rash. Contact your doctor if severe diarrhea or signs of allergic reaction occur. · This medication may reduce the effectiveness of oral contraceptives; use additional birth control if applicable. · Inform your doctor if your child has kidney disease, phenylketonuria (some suspensions contain phenylalanine), or is pregnant/breastfeeding. |