Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
AMCILL vs AMOXICILLIN PEDIATRIC
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Ampicillin is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis and death.
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.
Infections of the respiratory tract,Infections of the genitourinary tract,Meningitis,Septicemia,Endocarditis,Gastrointestinal infections,Prophylaxis of bacterial endocarditis
Treatment of infections caused by susceptible strains of microorganisms in conditions such as otitis media, sinusitis, pharyngitis, tonsillitis, pneumonia, bronchitis, urinary tract infections, skin and skin structure infections, and gonorrhea,Prophylaxis of infective endocarditis in patients undergoing dental or upper respiratory tract procedures (off-label but per ADA/AHA guidelines),Eradication of Helicobacter pylori (as part of combination therapy)
250-500 mg orally every 8 hours or 500 mg every 12 hours; for severe infections, up to 1 g every 6 hours intravenously.
250-500 mg orally every 8 hours or 500-875 mg orally every 12 hours for adults.
1-1.5 hours in normal renal function; prolonged to 7-10 hours in anuria.
Terminal elimination half-life: 1-1.5 hours in children with normal renal function; prolonged to 7-21 hours in anuria.
Partially metabolized by hydrolysis; primarily excreted unchanged in urine via renal tubular secretion and glomerular filtration.
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.
Renal: 60-80% unchanged; biliary: less than 10%; fecal: small amount.
Renal: 60-80% unchanged via glomerular filtration and tubular secretion; biliary: minor (<10%); fecal: <5%.
20% bound, primarily to albumin.
17-20% bound to serum proteins, primarily albumin.
0.3 L/kg; indicates distribution into extracellular fluid.
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.
Oral: 50-70% (variable, reduced by food); IM: nearly 100%.
Oral: 75-90% (absorption is rapid but incomplete; food does not significantly affect absorption).
For Cr Cl 30-50 m L/min: administer every 12 hours; for Cr Cl 10-29 m L/min: administer every 18-24 hours; for Cr Cl <10 m L/min: administer every 24 hours.
Cr Cl 10-30 m L/min: administer every 12 hours. Cr Cl <10 m L/min: administer every 24 hours. Hemodialysis: administer dose after dialysis.
No specific adjustments recommended for Child-Pugh A or B; use caution in severe hepatic impairment (Child-Pugh C) with monitoring.
No specific dose adjustment required for Child-Pugh A or B. Child-Pugh C: consider dose reduction based on clinical response.
Children >1 month: 25-50 mg/kg/day orally divided every 8 hours; for severe infections, up to 100 mg/kg/day IV divided every 6 hours. Maximum dose: 2 g/day.
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).
No specific dose adjustment required; monitor renal function and adjust based on creatinine clearance.
No specific dose adjustment based solely on age; assess renal function and adjust accordingly due to age-related decline in GFR.
No FDA black box warning.
No FDA black box warning.
Hypersensitivity reactions including anaphylaxis,Clostridioides difficile-associated diarrhea,Superinfection,Risk of seizures with high doses or renal impairment,Use caution in patients with mononucleosis (high risk of rash)
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.
Hypersensitivity to ampicillin, penicillins, or any component of the formulation,Infections caused by beta-lactamase-producing organisms
Hypersensitivity to amoxicillin or any penicillin derivative; history of anaphylactic reaction to beta-lactams.
Food does not significantly affect absorption; may be taken with or without meals. Avoid alcohol: may increase risk of disulfiram-like reaction (rare).
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.
FDA Pregnancy Category B. No evidence of teratogenicity in animal studies. First trimester: Not associated with major birth defects. Second and third trimesters: Use only if clearly needed; potential for altered gut flora and diarrhea in neonate.
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.
Ampicillin is excreted in breast milk in low concentrations (M/P ratio approximately 0.2). Compatible with breastfeeding; monitor infant for diarrhea or rash.
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.
Increased renal clearance during pregnancy may require higher doses to maintain therapeutic levels. Standard dosing is usually adequate for most indications; consider monitoring serum levels in severe infections.
Physiologic changes in pregnancy (increased renal blood flow, glomerular filtration rate, and volume of distribution) may lower serum concentrations. Standard dosing is generally adequate, but severe infections may require dose adjustment. No specific dose reduction recommended; monitor clinical response.
AMCILL (ampicillin) is a broad-spectrum penicillinase-sensitive penicillin. Use caution in patients with renal impairment; dose adjustment required for Cr Cl <30 m L/min. Monitor for hypersensitivity reactions, especially in patients with cephalosporin allergy. IV administration may cause phlebitis; rotate infusion sites. Not effective against penicillinase-producing organisms including Staphylococcus aureus.
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 (Cr Cl <30 m L/min) without dose adjustment. Monitor for rash, diarrhea, and hypersensitivity reactions.
Take exactly as prescribed; complete full course even if you feel better.,Notify your doctor if you develop rash, hives, or difficulty breathing.,May cause diarrhea; contact your doctor if severe or bloody.,Take with a full glass of water; avoid acidic beverages like orange juice.,Inform your doctor if you are pregnant, breastfeeding, or taking oral contraceptives (ampicillin may reduce efficacy).
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.
No interactions on record
"Amoxicillin may reduce the metabolism of Indinavir via inhibition of CYP3A4, leading to increased plasma concentrations of Indinavir. This can elevate the risk of Indinavir-related toxicities such as nephrolithiasis, hepatotoxicity, and gastrointestinal intolerance. Patients may experience exacerbated adverse effects without a corresponding increase in antiviral efficacy."
"Amoxicillin may inhibit the CYP3A4-mediated metabolism of nicardipine, a calcium channel blocker, leading to increased plasma concentrations of nicardipine. This can potentiate vasodilation and negative chronotropic effects, resulting in an increased risk of hypotension, bradycardia, and peripheral edema. Patients, especially those with pre-existing cardiovascular conditions, should be monitored for enhanced antihypertensive effects and adverse reactions when these drugs are coadministered."
"Amoxicillin may inhibit the metabolism of bortezomib through competitive inhibition of cytochrome P450 enzymes, particularly CYP3A4 and CYP2C19, potentially leading to increased bortezomib exposure. This interaction could result in enhanced toxicity of bortezomib, including peripheral neuropathy, myelosuppression, and gastrointestinal adverse effects. Clinicians should monitor for signs of bortezomib toxicity when amoxicillin is coadministered, especially in patients with pre-existing hepatic impairment or other risk factors."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about AMCILL vs AMOXICILLIN PEDIATRIC, answered by our medical review team.
AMCILL is a Penicillin Antibiotic that works by Ampicillin is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis and death.. AMOXICILLIN PEDIATRIC is a Penicillin Antibiotic that works by 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.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between AMCILL and AMOXICILLIN PEDIATRIC depend on the specific clinical indication. These are both Penicillin Antibiotic agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of AMCILL is: 250-500 mg orally every 8 hours or 500 mg every 12 hours; for severe infections, up to 1 g every 6 hours intravenously.. The standard adult dose of AMOXICILLIN PEDIATRIC is: 250-500 mg orally every 8 hours or 500-875 mg orally every 12 hours for adults.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between AMCILL and AMOXICILLIN PEDIATRIC in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. AMCILL is classified as Category C. FDA Pregnancy Category B. No evidence of teratogenicity in animal studies. First trimester: Not associated with major birth defects. Second and third trimesters: Use only if clearl. AMOXICILLIN PEDIATRIC is classified as Category A/B. 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 def. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.