Note: An ER tablet dose of 500 mg twice daily is clinically equivalent to an IR capsule dose of 250 mg 3 times daily; an ER tablet dose of 500 mg twice daily is NOT clinically equivalent to 500 mg 3 times daily of other cefaclor formulations.
Usual dosage range: Oral:
Immediate release: 250 to 500 mg every 8 hours.
Extended release: 500 mg every 12 hours.
Acute bacterial exacerbations of chronic bronchitis: Oral: Extended release: 500 mg every 12 hours for 7 days.
Pneumonia, community-acquired, outpatient empiric therapy (patients with comorbidities): Oral: Immediate release: 500 mg every 8 hours as part of an appropriate combination regimen (ATS/IDSA [Metlay 2019]; manufacturer's labeling). Duration is for a minimum of 5 days; patients should be clinically stable with normal vital signs before discontinuing therapy (ATS/IDSA [Metlay 2019]).
Streptococcal pharyngitis, group A (alternative agent for mild, nonanaphylactic penicillin allergy):
Note: Cephalosporin selection depends on the type of hypersensitivity reaction to penicillin. To avoid the development of resistance, narrower spectrum cephalosporins (eg, cephalexin or cefadroxil) are preferred when possible (IDSA [Shulman 2012]; Pichichero 2022).
Oral: Immediate release: 250 mg every 8 hours for 10 days (IDSA [Shulman 2012]; manufacturer's labeling).
Urinary tract infection (alternative agent):
Note: Use only when first-line agents cannot be used; limited evidence suggests inferior efficacy of oral beta-lactams (IDSA/ESCMID [Gupta 2011]).
Cystitis, acute uncomplicated or acute simple cystitis (infection limited to the bladder without signs/symptoms of upper tract, prostate, or systemic infection), treatment: Oral: Immediate release: 250 mg every 8 hours for 5 to 7 days (IDSA/ESCMID [Gupta 2011]; Iravani 1992; Leigh 2000).
Cystitis, prophylaxis for recurrent infection (off-label use):
Note: May be considered in nonpregnant women with bothersome, frequently recurrent cystitis despite nonantimicrobial preventive measures. The optimal duration has not been established; duration ranges from 3 to 12 months, with periodic reassessment (AUA/CUA/SUFA [Anger 2019]; Gupta 2021).
Continuous prophylaxis: Oral: Immediate release: 250 mg once daily (Brumfitt 1995).
Urinary tract infection, complicated (including pyelonephritis): Oral: Immediate release: 500 mg 3 times daily for 10 to 14 days (Hyslop 1992; IDSA/ESCMID [Gupta 2011]). Note: Oral beta-lactam therapy should generally follow appropriate parenteral therapy (Hooton 2021b; IDSA/ESCMID [Gupta 2011]).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Manufacturer’s labeling:
Oral:
Mild to severe impairment: No dosage adjustment necessary; use with caution in patients with anuria (half-life is prolonged).
Hemodialysis: There are no dosage adjustments provided in the manufacturer's labeling; hemodialysis shortens half-life by 25% to 30%.
Alternative recommendations (off-label dosing) (Aronoff 2007):
Oral, immediate-release:
Mild to severe impairment: No dosage adjustment necessary.
End-stage renal disease (ESRD) on intermittent hemodialysis (IHD) (administer after hemodialysis on dialysis days): Supplement with 250 to 500 mg after dialysis.
Peritoneal dialysis: Administer 250 to 500 mg every 8 hours.
There are no dosage adjustments provided in the manufacturer’s labeling.
(For additional information see "Cefaclor: Pediatric drug information")
General dosing, susceptible infection: Mild to moderate infection: Infants, Children, and Adolescents: Oral, immediate release: 20 to 40 mg/kg/day divided every 8 to 12 hours. Maximum daily dose: 1,500 mg/day (Red Book [AAP 2015]).
Bronchitis: Adolescents ≥16 years: Extended release tablet: Note: An extended release tablet dose of 500 mg twice daily is clinically equivalent to an immediate release capsule dose of 250 mg 3 times daily; an extended release tablet dose of 500 mg twice daily is NOT clinically equivalent to 500 mg 3 times daily of other cefaclor formulations.
Acute bacterial exacerbations of chronic bronchitis: Oral: Extended release: 500 mg every 12 hours for 7 days.
Secondary bacterial infection of acute bronchitis: Oral: Extended release: 500 mg every 12 hours for 7 days.
Lower respiratory tract infections: Infants, Children, and Adolescents: Oral immediate release: 20 to 40 mg/kg/day divided every 8 hours; maximum daily dose: 1,000 mg/day. If beta-hemolytic streptococcus/S. pyogenes suspected, treat for at least 10 days.
Otitis media: Infants, Children, and Adolescents: Oral immediate release: 40 mg/kg/day divided every 8 to 12 hours (oral suspension) or every 8 hours (capsule); maximum daily dose: 1,000 mg/day. If beta-hemolytic streptococcus/S. pyogenes suspected, treat for at least 10 days. Note: Cefaclor is not a recommended treatment option in the AAP guidelines (Lieberthal 2013).
Pharyngitis/tonsillitis: Infants, Children, and Adolescents: Oral immediate release: 20 mg/kg/day divided every 8 to 12 hours (oral suspension) or every 8 hours (capsule); maximum daily dose: 1,000 mg/day. If beta-hemolytic streptococcus/S. pyogenes confirmed, treat for at least 10 days. Note: Cefaclor is not a recommended treatment option in the IDSA guidelines and is not considered preferred by the AHA due to its broad spectrum (AHA [Gerber 2009], IDSA [Shulman 2012]).
Skin and skin structure infections, uncomplicated: Infants, Children, and Adolescents: Oral: Immediate release: 20 to 40 mg/kg/day divided every 8 hours; maximum daily dose: 1,000 mg/day. If due to beta-hemolytic streptococcus/S. pyogenes, treat for at least 10 days.
Urinary tract infections: Infants, Children, and Adolescents: Oral: Immediate release: 20 to 40 mg/kg/day divided every 8 hours; maximum daily dose: 1,000 mg/day.
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Manufacturer's labeling:
Oral, immediate release: Infants, Children, and Adolescents: There are no dosage adjustments provided in the manufacturer's labeling; however, half-life is increased in anuric patients; use with caution.
Oral, extended release: There are no dosage adjustments provided in the manufacturer's labeling.
Alternative recommendations (Aronoff 2007): Dosing based on usual dose of 20 to 40 mg/kg/day in divided doses every 8 to 12 hours
Infants, Children, and Adolescents: Oral, immediate release:
GFR ≥10 mL/minute/1.73 m2: No dosage adjustment necessary.
GFR <10 mL/minute/1.73 m2: Administer 50% of the recommended dose.
End-stage renal disease (ERD) on intermittent hemodialysis (IHD) (supplemental dose posthemodialysis needed): Administer 50% of the recommended dose.
Peritoneal dialysis: Administer 50% of the recommended dose.
Hemodialysis: Hemodialysis shortens half-life by 25% to 35%
Moderately dialyzable (20% to 50%) (Aronoff 2007)
There are no dosage adjustments provided in the manufacturer's labeling.
Refer to adult dosing.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
Capsule, Oral:
Generic: 250 mg, 500 mg
Suspension Reconstituted, Oral:
Generic: 125 mg/5 mL (150 mL); 250 mg/5 mL (150 mL [DSC]); 375 mg/5 mL (100 mL)
Tablet Extended Release 12 Hour, Oral:
Generic: 500 mg
Yes
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
Capsule, Oral:
Generic: 250 mg, 500 mg
Suspension Reconstituted, Oral:
Generic: 125 mg/5 mL ([DSC]); 250 mg/5 mL ([DSC]); 375 mg/5 mL ([DSC])
Oral:
Capsules and oral suspension: Administer without regard to meals; shake oral suspension well before using
ER tablets: Do not chew, crush, or split; administer with or within 1 hour of food.
Bariatric surgery: Some institutions may have specific protocols that conflict with these recommendations; refer to institutional protocols as appropriate. Switch to IR formulation. Capsule may be opened and contents sprinkled onto soft food of choice. Patient should be instructed to swallow the mixture without biting down or chewing.
Oral: Administer around-the-clock to promote less variation in peak and trough serum levels.
Capsules and oral suspension: Administer without regard to meals; shake oral suspension well before using.
Extended release tablets: Do not chew, crush, or split; administer with or within 1 hour of food.
Acute bacterial exacerbations of chronic bronchitis (extended-release tablets only): Treatment of acute bacterial exacerbations of chronic bronchitis due to Haemophilus influenzae (excluding beta-lactamase-negative, ampicillin-resistant strains only), Moraxella catarrhalis, or Streptococcus pneumoniae.
Lower respiratory tract infections (capsules and oral suspension only): Treatment of lower respiratory tract infections, including pneumonia, caused by S. pneumoniae, H. influenzae, and Streptococcus pyogenes.
Otitis media (capsules and oral suspension only): Treatment of otitis media caused by S. pneumoniae, H. influenzae, staphylococci, and S. pyogenes.
Skin and skin structure infections, uncomplicated: Treatment of uncomplicated skin and skin structure infections due to Staphylococcus aureus (methicillin-susceptible) or S. pyogenes (capsules and oral suspension only).
Streptococcal pharyngitis, group A: Treatment of pharyngitis and tonsillitis due to S. pyogenes.
Urinary tract infection (capsules and oral suspension only): Treatment of urinary tract infections, including pyelonephritis and cystitis, caused by Escherichia coli, Proteus mirabilis, Klebsiella spp, and coagulase-negative staphylococci.
Cefaclor may be confused with cephalexin
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
1% to 10%:
Dermatologic: Pruritus (1%)
Gastrointestinal: Abdominal pain (2%), diarrhea (3% to 4%), nausea (3%)
Genitourinary: Genital pruritus (≤2%), vaginitis (≤2%), vulvovaginal candidiasis (≤2%)
Hematologic & oncologic: Eosinophilia (2%)
Hepatic: Increased serum transaminases (3%; including increased serum alanine aminotransferase, increased serum alkaline phosphatase, increased aspartate aminotransferase)
Hypersensitivity: Hypersensitivity reactions (2%)
Nervous system: Headache (5%)
Neuromuscular & skeletal: Back pain (1%)
<1%:
Cardiovascular: Edema (including peripheral edema) (Romano 2008), heart failure, palpitations
Dermatologic: Diaphoresis, maculopapular rash (Romano 2008), skin rash, urticaria (Romano 2008)
Endocrine & metabolic: Decreased serum albumin, decreased serum calcium, decreased serum sodium, increased gamma-glutamyl transferase, increased serum phosphate, increased serum potassium, increased serum sodium, menstrual disease
Gastrointestinal: Anorexia, constipation, dyspepsia, flatulence, gastritis, vomiting
Genitourinary: Abnormal urine test finding, dysmenorrhea, dysuria, leukorrhea, nocturia
Hematologic & oncologic: Decreased hemoglobin, decreased red blood cells, increased MCV, lymphocytopenia, positive direct Coombs’ test, thrombocytopenia
Hepatic: Increased serum bilirubin
Hypersensitivity: Serum sickness
Nervous system: Anxiety, dizziness, drowsiness, insomnia, malaise, nervousness, pain, tremor
Neuromuscular & skeletal: Arthralgia, increased creatine phosphokinase in blood specimen, myalgia, neck pain
Renal: Increased blood urea nitrogen, increased serum creatinine, interstitial nephritis
Respiratory: Asthma
Postmarketing:
Cardiovascular: Hypotension, syncope, vasodilation
Dermatologic: Acute generalized exanthematous pustulosis (Kwah 2005), erythema of skin (Romano 2008), Stevens-Johnson syndrome, toxic epidermal necrolysis
Gastrointestinal: Clostridioides difficile colitis
Hematologic & oncologic: Agranulocytosis, aplastic anemia, hemolytic anemia, leukopenia, neutropenia
Hepatic: Cholestatic jaundice, hepatitis
Hypersensitivity: Anaphylactic shock (Romano 2008), anaphylaxis (Grouhi 1999), angioedema (Romano 2008), facial edema, nonimmune anaphylaxis
Nervous system: Agitation, confusion, hallucination, hypertonia, hyperactive behavior, paresthesia, vertigo
Hypersensitivity to cefaclor, other cephalosporins, or any component of the formulation.
Documentation of allergenic cross-reactivity for beta-lactams (eg, penicillins and cephalosporins) is limited. However, because of similarities in chemical structure and/or pharmacologic actions, the possibility of cross-sensitivity cannot be ruled out with certainty.
Concerns related to adverse effects:
• Hypersensitivity: Anaphylactic reactions have occurred. If a serious hypersensitivity reaction occurs, discontinue and institute emergency supportive measures, including airway management and treatment (eg, epinephrine, antihistamines, and/or corticosteroids).
• Penicillin allergy: Use with caution in patients with a history of penicillin allergy.
• Superinfection: Prolonged use may result in fungal or bacterial superinfection, including C. difficile-associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months postantibiotic treatment.
Disease-related concerns:
• Gastrointestinal disease: Use with caution in patients with a history of gastrointestinal disease, particularly colitis.
• H. influenzae infections: Beta-lactamase-negative, ampicillin-resistant (BLNAR) strains of H. influenzae should be considered resistant to cefaclor.
• Renal impairment: Use with caution in patients with renal impairment.
Dosage form specific issues:
• Benzyl alcohol and derivatives: Some dosage forms may contain sodium benzoate/benzoic acid; benzoic acid (benzoate) is a metabolite of benzyl alcohol; large amounts of benzyl alcohol (≥99 mg/kg/day) have been associated with a potentially fatal toxicity (“gasping syndrome”) in neonates; the “gasping syndrome” consists of metabolic acidosis, respiratory distress, gasping respirations, CNS dysfunction (including convulsions, intracranial hemorrhage), hypotension, and cardiovascular collapse (AAP ["Inactive" 1997]; CDC, 1982); some data suggests that benzoate displaces bilirubin from protein binding sites (Ahlfors, 2001); avoid or use dosage forms containing benzyl alcohol derivative with caution in neonates. See manufacturer’s labeling.
• Extended-release tablet: An extended-release tablet dose of 500 mg twice daily is clinically equivalent to an immediate-release capsule dose of 250 mg 3 times daily; an extended-release tablet dose of 500 mg twice daily is NOT clinically equivalent to 500 mg 3 times daily of other cefaclor formulations.
May cause serum sickness-like reaction (estimated incidence ranges from 0.024% to 0.2% per drug course); majority of reactions have occurred in children <5 years of age with symptoms of fever, rash, erythema multiforme, and arthralgia, often occurring during the second or third exposure.
Substrate of OAT1/3
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the Lexicomp drug interactions program by clicking on the “Launch drug interactions program” link above.
Aminoglycosides: Cephalosporins may enhance the nephrotoxic effect of Aminoglycosides. Cephalosporins may decrease the serum concentration of Aminoglycosides. Risk C: Monitor therapy
Bacillus clausii: Antibiotics may diminish the therapeutic effect of Bacillus clausii. Management: Bacillus clausii should be taken in between antibiotic doses during concomitant therapy. Risk D: Consider therapy modification
BCG (Intravesical): Antibiotics may diminish the therapeutic effect of BCG (Intravesical). Risk X: Avoid combination
BCG Vaccine (Immunization): Antibiotics may diminish the therapeutic effect of BCG Vaccine (Immunization). Risk C: Monitor therapy
Cholera Vaccine: Antibiotics may diminish the therapeutic effect of Cholera Vaccine. Management: Avoid cholera vaccine in patients receiving systemic antibiotics, and within 14 days following the use of oral or parenteral antibiotics. Risk X: Avoid combination
Furosemide: May enhance the nephrotoxic effect of Cephalosporins. Risk C: Monitor therapy
Immune Checkpoint Inhibitors: Antibiotics may diminish the therapeutic effect of Immune Checkpoint Inhibitors. Risk C: Monitor therapy
Lactobacillus and Estriol: Antibiotics may diminish the therapeutic effect of Lactobacillus and Estriol. Risk C: Monitor therapy
Probenecid: May increase the serum concentration of Cephalosporins. Risk C: Monitor therapy
Sodium Picosulfate: Antibiotics may diminish the therapeutic effect of Sodium Picosulfate. Management: Consider using an alternative product for bowel cleansing prior to a colonoscopy in patients who have recently used or are concurrently using an antibiotic. Risk D: Consider therapy modification
Typhoid Vaccine: Antibiotics may diminish the therapeutic effect of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. Management: Avoid use of live attenuated typhoid vaccine (Ty21a) in patients being treated with systemic antibacterial agents. Postpone vaccination until 3 days after cessation of antibiotics and avoid starting antibiotics within 3 days of last vaccine dose. Risk D: Consider therapy modification
Vitamin K Antagonists (eg, warfarin): Cephalosporins may enhance the anticoagulant effect of Vitamin K Antagonists. Risk C: Monitor therapy
The bioavailability of cefaclor extended-release tablets is decreased 23% and the maximum concentration is decreased 67% when taken on an empty stomach. Management: Administer with food.
An increased risk of teratogenic effects has not been observed following maternal use of cefaclor.
Small amounts of cefaclor are excreted in breast milk. The manufacturer recommends that caution be exercised when administering cefaclor to nursing women. Nondose-related effects could include modification of bowel flora.
Extended release tablets should be taken with or within 1 hour of food.
Monitor renal function. Observe for signs of anaphylaxis during first dose.
Inhibits bacterial cell wall synthesis by binding to one or more of the penicillin-binding proteins (PBPs), which in turn inhibits the final transpeptidation step of peptidoglycan synthesis in bacterial cell walls, thus inhibiting cell wall biosynthesis. Bacteria eventually lyse due to ongoing activity of cell wall autolytic enzymes (autolysins and murein hydrolases) while cell wall assembly is arrested.
Absorption: Oral: Well absorbed; acid stable
Distribution: Distributes into tissues and fluids including bone, pleural and synovial fluid
Protein binding: 25% (Aronoff 2007)
Half-life elimination: 0.6 to 0.9 hours; prolonged with renal impairment (2.3 to 2.8 hours in anuria)
Time to peak: Capsules, oral suspension: 30 to 60 minutes; Extended-release tablets: 2.5 hours
Excretion: Urine (60% to 85% as unchanged drug)
Capsules (Cefaclor Oral)
250 mg (per each): $2.59
500 mg (per each): $5.06
Suspension (reconstituted) (Cefaclor Oral)
125 mg/5 mL (per mL): $4.20
375 mg/5 mL (per mL): $6.30
Tablet, 12-hour (Cefaclor ER Oral)
500 mg (per each): $23.32
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.
