Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
CEFACLOR vs ANCEF IN DEXTROSE 5% IN PLASTIC CONTAINER
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Bactericidal; inhibits cell wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan cross-linking.
Cefazolin is a first-generation cephalosporin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting transpeptidation and disrupting peptidoglycan cross-linking. This leads to cell lysis and death, primarily in actively dividing bacteria.
Acute otitis media,Acute exacerbations of chronic bronchitis,Pharyngitis/tonsillitis,Uncomplicated skin and skin structure infections,Urinary tract infections,Lower respiratory tract infections including pneumonia
Perioperative prophylaxis,Respiratory tract infections,Urinary tract infections,Skin and soft tissue infections,Biliary tract infections,Bone and joint infections,Septicemia,Endocarditis,Genital infections (e.g., prostatitis, epididymitis),Off-label: Surgical prophylaxis in certain procedures
250-500 mg orally every 8 hours
For uncomplicated infections: 1-2 g IV every 8 hours. For severe infections: up to 2 g IV every 4 hours. Administered as an IV infusion over 30-60 minutes.
Terminal elimination half-life: 0.5-1 hour; prolonged to 2-3 hours in renal impairment
1.8 hours (normal renal function); prolonged to 10-30 hours in severe renal impairment (Cr Cl <10 m L/min)
Hepatic (minor); primarily renally excreted unchanged.
Cefazolin is minimally metabolized; primarily undergoes renal tubular secretion and glomerular filtration. Not significantly metabolized by cytochrome P450 enzymes.
Renal: 60-85% unchanged in urine within 8 hours; biliary/fecal: minor, ~5%
Renal: >80% unchanged via glomerular filtration and tubular secretion; biliary/fecal: <1%
25-50% bound to plasma proteins, primarily albumin
80-86% bound to serum albumin
0.35-0.5 L/kg; distributes into most body tissues and fluids, including middle ear, sinus, and respiratory secretions
0.12-0.16 L/kg; primarily in extracellular fluid
Oral: 95% well absorbed; food does not significantly affect absorption
IM: ~85% (peak levels in 0.5-2 hours); IV: 100%
Cr Cl 10-50 m L/min: 50% of usual dose every 8 hours; Cr Cl <10 m L/min: 50% of usual dose every 12 hours
Cr Cl 35-54 m L/min: 1-2 g every 8 hours. Cr Cl 11-34 m L/min: 1-2 g every 12 hours. Cr Cl <10 m L/min: 1-2 g every 24-48 hours. For patients on hemodialysis, administer 1-2 g after each dialysis session.
No adjustment required for mild to moderate hepatic impairment; safety in severe impairment not established
No dosage adjustment required for hepatic impairment. Cefazolin is primarily renally eliminated.
20-40 mg/kg/day orally divided every 8 hours; maximum 1 g/day
For children >1 month: 25-100 mg/kg/day IV divided every 6-8 hours. For severe infections: up to 100 mg/kg/day IV divided every 6-8 hours. Maximum dose: 6 g/day.
No specific adjustment, but monitor renal function; initiate at lower end of dosing range due to age-related renal decline
Adjust dose based on renal function. Calculate Cr Cl and follow renal adjustment guidelines. No additional geriatric-specific modifications beyond renal consideration.
None.
None
Hypersensitivity reactions, including anaphylaxis,Clostridium difficile-associated diarrhea,Seizures (especially with renal impairment),Prolonged PT in patients on anticoagulants,False-positive urine glucose test
Hypersensitivity reactions: Cross-allergenicity with other beta-lactams; caution in penicillin-allergic patients,Acute generalized exanthematous pustulosis (AGEP),Clostridioides difficile-associated diarrhea (CDAD),Seizures at high doses or in renal impairment,Nephrotoxicity (especially with aminoglycosides or loop diuretics),Hemolytic anemia (rare),Interference with glucose and protein tests,Use in renal impairment: dose adjustment required,Pregnancy category B: use only if clearly needed,Geriatric use: increased risk of adverse effects
Known hypersensitivity to cephalosporins or any component,Previous immediate hypersensitivity reaction to penicillins (cross-sensitivity)
Hypersensitivity to cefazolin or any cephalosporin,Severe immediate hypersensitivity (e.g., anaphylaxis) to penicillins or other beta-lactams
No significant food interactions; cefaclor can be taken with or without food.,Absorption may be slightly delayed with food but total bioavailability is unaffected.,Avoid grapefruit juice? No known interaction.,Alcohol: No specific interaction, but caution as it may increase side effects like gastrointestinal upset.
No specific food interactions. Avoid alcohol during therapy and for 72 hours post-treatment due to risk of disulfiram-like reaction (cefazolin has a methylthiotetrazole side chain). Patients with diabetes should account for dextrose content (5 g/100 m L) in their carbohydrate intake.
First trimester: No increased risk of major congenital malformations based on limited human data; animal studies show no teratogenicity at clinically relevant doses. Second/third trimester: No known fetal risks; Cefaclor crosses the placenta with fetal serum concentrations approximately 10-20% of maternal levels.
Pregnancy Category B. No evidence of risk in humans based on animal studies and human data; however, adequate studies in pregnant women are lacking. No known teratogenic effects in first trimester; use only if clearly needed.
Cefaclor is excreted into human breast milk in low concentrations (M/P ratio approximately 0.05-0.10). Considered compatible with breastfeeding by the American Academy of Pediatrics; use with caution in nursing infants with potential for diarrhea or allergic sensitization.
Cefazolin is excreted into breast milk in low concentrations (M/P ratio approximately 0.2-0.5). Considered compatible with breastfeeding; monitor for potential gastrointestinal effects in the infant.
No dose adjustment required in pregnancy; pharmacokinetic changes (increased volume of distribution, renal clearance) do not necessitate dose modification due to wide therapeutic index.
Increased glomerular filtration rate during pregnancy may require higher doses or more frequent dosing to achieve therapeutic concentrations; specific dose adjustment not established; monitor clinical response.
Cefaclor is a second-generation cephalosporin with activity against both Gram-positive and Gram-negative organisms, but not Pseudomonas or MRSA.,It is stable against some beta-lactamases, but resistance can occur via extended-spectrum beta-lactamases (ESBLs).,Dose adjustment is required in renal impairment (Cr Cl <40 m L/min).,It is available as an oral suspension and capsules; suspension must be refrigerated and shaken well before use.,Cefaclor may cause a serum sickness-like reaction, especially in children, characterized by rash, arthralgia, and fever.,It has a short half-life (0.6-0.9 hours) and is usually dosed every 8 hours.,Avoid use in patients with immediate hypersensitivity to penicillins due to cross-reactivity risk (about 10%).
For surgical prophylaxis, administer within 60 minutes before incision. Use extended infusion (over 1-2 hours) for critically ill patients to optimize pharmacokinetic/pharmacodynamic target attainment. Monitor renal function given cefazolin excretion; adjust dose for Cr Cl <55 m L/min. Avoid in patients with immediate-type hypersensitivity to penicillins (10% cross-reactivity risk). In obese patients (BMI ≥40 kg/m²), consider doubling the standard dose (2 g IV) for adequate tissue penetration.
Take this medication exactly as prescribed, usually every 8 hours, with or without food.,Complete the full course of therapy even if you feel better to prevent bacterial resistance.,Shake the oral suspension well before each dose and refrigerate it; discard any unused portion after 14 days.,Contact your healthcare provider if you develop severe diarrhea, rash, joint pain, or fever.,Inform your doctor if you have a history of allergic reactions to penicillins or cephalosporins.,Do not take this medication if you are allergic to cefaclor or any other cephalosporin antibiotic.,If a dose is missed, take it as soon as remembered unless it is almost time for the next dose; do not double the dose.
Complete the full course of antibiotics as prescribed, even if you feel better.,Report any signs of allergic reaction (rash, itching, difficulty breathing, swelling of face or throat) to your healthcare provider immediately.,If you are diabetic, note that each 1% dextrose solution provides 3.4 kcal/g; monitor blood glucose levels closely.,The medication is given intravenously; ensure the IV site is clean and free from redness, swelling, or pain.,Avoid alcohol during treatment and for at least 72 hours after the last dose to prevent disulfiram-like reactions (flushing, nausea, vomiting).
"Phenindione, a vitamin K antagonist anticoagulant, potentiates the effect of cefaclor, a second-generation cephalosporin antibiotic. Cefaclor may reduce vitamin K production by suppressing intestinal flora, thereby enhancing the anticoagulant effect of phenindione. This interaction can lead to an increased international normalized ratio (INR) and risk of bleeding, particularly in patients with poor nutritional status or prolonged antibiotic therapy."
"Dicoumarol may increase the anticoagulant activities of Cefaclor."
"Warfarin may increase the anticoagulant activities of Cefaclor."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about CEFACLOR vs ANCEF IN DEXTROSE 5% IN PLASTIC CONTAINER, answered by our medical review team.
CEFACLOR is a Cephalosporin Antibiotic that works by Bactericidal; inhibits cell wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan cross-linking.. ANCEF IN DEXTROSE 5% IN PLASTIC CONTAINER is a Cephalosporin Antibiotic that works by Cefazolin is a first-generation cephalosporin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting transpeptidation and disrupting peptidoglycan cross-linking. This leads to cell lysis and death, primarily in actively dividing bacteria.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between CEFACLOR and ANCEF IN DEXTROSE 5% IN PLASTIC CONTAINER depend on the specific clinical indication. These are both Cephalosporin 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 CEFACLOR is: 250-500 mg orally every 8 hours. The standard adult dose of ANCEF IN DEXTROSE 5% IN PLASTIC CONTAINER is: For uncomplicated infections: 1-2 g IV every 8 hours. For severe infections: up to 2 g IV every 4 hours. Administered as an IV infusion over 30-60 minutes.. 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 CEFACLOR and ANCEF IN DEXTROSE 5% IN PLASTIC CONTAINER 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. CEFACLOR is classified as Category A/B. First trimester: No increased risk of major congenital malformations based on limited human data; animal studies show no teratogenicity at clinically relevant doses. Second/third t. ANCEF IN DEXTROSE 5% IN PLASTIC CONTAINER is classified as Category C. Pregnancy Category B. No evidence of risk in humans based on animal studies and human data; however, adequate studies in pregnant women are lacking. No known teratogenic effects in. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.