Drug class: Second Generation Cephalosporins
VA class: AM116
CAS number: 53994-73-3

Medically reviewed by Drugs.com on Sep 28, 2023. Written by ASHP.

Introduction

Antibacterial; β-lactam antibiotic; second generation cephalosporin.^{167 168 169 a}

Uses for Cefaclor

Acute Otitis Media (AOM)

Treatment of AOM caused by Streptococcus pneumoniae, Haemophilus influenzae, staphylococci, or S. pyogenes (group A β-hemolytic streptococci).^{167 169} (See Haemophilus influenzae Infections under Cautions.)

When anti-infectives indicated, AAP recommends high-dose amoxicillin or amoxicillin and clavulanate as drugs of choice for initial treatment of AOM; certain cephalosporins (cefdinir, cefpodoxime, cefuroxime, ceftriaxone) recommended as alternatives for initial treatment in penicillin-allergic patients without a history of severe and/or recent penicillin-allergic reactions.¹⁶⁵

Pharyngitis and Tonsillitis

Treatment of pharyngitis and tonsillitis caused by S. pyogenes (group A β-hemolytic streptococci).^{124 135 152 153 167 168 169} Generally effective in eradicating S. pyogenes from nasopharynx; efficacy in prevention of subsequent rheumatic fever not established to date.^{167 168 169}

AAP, IDSA, AHA, and others recommend a penicillin regimen (10 days of oral penicillin V or oral amoxicillin or single dose of IM penicillin G benzathine) as treatment of choice for S. pyogenes pharyngitis and tonsillitis;^{100 101 116 117} other anti-infectives (oral cephalosporins, oral macrolides, oral clindamycin) recommended as alternatives in penicillin-allergic patients.^{100 101 116 117}

If an oral cephalosporin used, 10 day regimen of first generation cephalosporin (cefadroxil, cephalexin) preferred instead of other cephalosporins with broader spectrums of activity (e.g., cefaclor, cefdinir, cefixime, cefpodoxime, cefuroxime).^{100 116 117}

Respiratory Tract Infections

Treatment of lower respiratory tract infections, including pneumonia, caused by susceptible H. influenzae, S. pneumoniae, or S. pyogenes (group A β-hemolytic streptococci).^{167 169} (See Haemophilus influenzae Infections under Cautions.)

Treatment of mild to moderate acute bacterial exacerbations of chronic bronchitis caused by susceptible H. influenzae (β-lactamase negative strains only), Moraxella catarrhalis (including β-lactamase producing strains), or S. pneumoniae.¹⁶⁸ (See Haemophilus influenzae Infections under Cautions.)

Treatment of secondary bacterial infections of acute bronchitis caused by susceptible H. influenzae (β-lactamase negative strains only) or M. catarrhalis (including β-lactamase producing strains).¹⁶⁸ (See Haemophilus influenzae Infections under Cautions.)

Skin and Skin Structure Infections

Uncomplicated skin and skin structure infections caused by susceptible Staphylococcus aureus (methicillin-susceptible [oxacillin-susceptible] strains only)^{136 167 168 169} or S. pyogenes.^{136 167}

Urinary Tract Infections (UTIs)

Treatment of UTIs (including pyelonephritis and cystitis) caused by susceptible Escherichia coli, Proteus mirabilis, Klebsiella, or coagulase-negative staphylococci.¹⁶⁷

Cefaclor Dosage and Administration

Administration

Oral Administration

Administer orally.^{167 168 169}

Conventional capsules or oral suspension: Administer without regard to meals.^{167 169}

Extended-release tablets: Administer with meals or within 1 hour of eating.¹⁶⁸ (See Food under Pharmacokinetics.) Do not cut, crush, or chew.¹⁶⁸

Reconstitution

Reconstitute oral suspension at time of dispensing by adding amount of water specified on the container in 2 portions; shake well after each addition.¹⁶⁹

Reconstituted suspension contains 125, 187, 250, or 375 mg of cefaclor/5 mL.¹⁶⁹

Shake suspension well prior to administration of each dose.¹⁶⁹

Dosage

Available as cefaclor monohydrate; dosage expressed in terms of anhydrous cefaclor.^{167 168 169}

Pediatric Patients

General Pediatric Dosage

Oral

Children beyond neonatal period: AAP recommends 20–40 mg/kg daily in 2 or 3 equally divided doses for treatment of mild or moderate infections.¹⁰⁰ AAP states the drug is inappropriate for treatment of severe infections.¹⁰⁰

Acute Otitis Media (AOM)

Oral

Children ≥1 month of age (capsules or oral suspension): 40 mg/kg daily in divided doses every 8 or 12 hours.^{167 169}

Pharyngitis and Tonsillitis

Oral

Children ≥1 month of age (capsules or oral suspension): 20 mg/kg daily in divided doses every 8 or 12 hours for 10 days.^{167 169} For more severe infections or those caused by less-susceptible organisms, 40 mg/kg daily in divided doses every 8 hours.^{167 169}

Respiratory Tract Infections

Oral

Children ≥1 month of age (capsules or oral suspension): 20 mg/kg daily in divided doses every 8 hours (as capsules or oral suspension) for lower respiratory tract infections.^{167 169} For more severe infections or those caused by less-susceptible organisms, 40 mg/kg daily in divided doses every 8 hours.^{167 169}

Skin and Skin Structure Infections

Oral

Children ≥1 month of age (capsules or oral suspension): 20 mg/kg daily in divided doses every 8 hours (as capsules or oral suspension).^{167 169} For more severe infections or those caused by less susceptible organisms, 40 mg/kg daily in divided doses every 8 hours.^{167 169}

Urinary Tract Infections (UTIs)

Oral

Children ≥1 month of age (capsules or oral suspension): 20 mg/kg daily in divided doses every 8 hours.^{167 169} For more severe infections or those caused by less susceptible organisms, 40 mg/kg daily in divided doses every 8 hours.^{167 169}

Adults

Acute Otitis Media (AOM)

Oral

Capsules or oral suspension: 250 mg every 8 hours.^{167 169} For more severe infections or those caused by less susceptible organisms, 500 mg every 8 hours.^{167 169}

Pharyngitis and Tonsillitis

Oral

Capsules or oral suspension: 250 mg every 8 hours.^{167 169} For more severe infections or those caused by less susceptible organisms, 500 mg every 8 hours for at least 10 days.^{167 169}

Extended-release tablets: 375 mg every 12 hours for 10 days.¹⁶⁸

Respiratory Tract Infections

Lower Respiratory Tract Infections

Oral

Capsules or oral suspension: 250 mg every 8 hours.^{167 169} For more severe infections (e.g., pneumonia) or those caused by less susceptible organisms, 500 mg every 8 hours.^{167 169}

Acute Bacterial Exacerbations of Chronic Bronchitis

Oral

Extended-release tablets: 500 mg every 12 hours for 7 days.¹⁶⁸

Secondary Bacterial Infections of Acute Bronchitis

Oral

Extended-release tablets: 500 mg every 12 hours for 7 days.¹⁶⁸

Skin and Skin Structure Infections

Oral

Capsules or oral suspension: 250 mg every 8 hours.^{167 169} For more severe infections or those caused by less susceptible organisms, 500 mg every 8 hours.^{167 169}

Extended-release tablets: 375 mg every 12 hours for 7–10 days.¹⁶⁸

Urinary Tract Infections (UTIs)

Oral

Capsules or oral suspension: 250 mg every 8 hours.^{167 169} For more severe infections or those caused by less susceptible organisms, 500 mg every 8 hours.^{167 169}

Prescribing Limits

Pediatric Patients

Oral

Capsules or oral suspension: Maximum 1 g daily.^{167 169}

Special Populations

Renal Impairment

Dosage adjustments not usually required in moderate or severe renal impairment.^{167 169} Use with caution in those with markedly impaired renal function.^{167 169} (See Renal Impairment under Cautions.)

Geriatric Patients

No age-related dosage adjustments required.¹⁶⁸ Select dosage with caution because of age-related decreases in renal function.^{167 169}

Cautions for Cefaclor

Contraindications

• Known hypersensitivity to cefaclor, any other cephalosporin, or any ingredient in the formulation.^{167 168 169}

Warnings/Precautions

Warnings

Superinfection/Clostridium difficile-associated Diarrhea and Colitis

Possible emergence and overgrowth of nonsusceptible bacteria or fungi.^{167 168 169} Careful observation of the patient is essential.^{167 168 169} Institute appropriate therapy if superinfection occurs.^{167 168 169}

Treatment with anti-infectives alters normal colon flora and may permit overgrowth of Clostridium difficile.^{142 167 168 169} C. difficile infection (CDI) and C. difficile-associated diarrhea and colitis (CDAD; also known as antibiotic-associated diarrhea and colitis or pseudomembranous colitis) reported with nearly all anti-infectives, including cefaclor, and may range in severity from mild diarrhea to fatal colitis.^{142 167 168 169} C. difficile produces toxins A and B which contribute to development of CDAD;^{142 168 169} hypertoxin-producing strains of C. difficile are associated with increased morbidity and mortality since they may be refractory to anti-infectives and colectomy may be required.^{168 169}

Consider CDAD if diarrhea develops during or after therapy and manage accordingly.^{142 167 168 169} Obtain careful medical history since CDAD may occur as late as 2 months or longer after anti-infective therapy is discontinued.^{142 168 169}

If CDAD is suspected or confirmed, discontinue anti-infectives not directed against C. difficile whenever possible.^{142 168 169} Initiate appropriate supportive therapy (e.g., fluid and electrolyte management, protein supplementation), anti-infective therapy directed against C. difficile (e.g., metronidazole, vancomycin), and surgical evaluation as clinically indicated.^{142 167 168 169}

Haemophilus influenza Infections

β-lactamase-negative, ampicillin-resistant (BLNAR) strains of H. influenzae should be considered resistant to cefaclor despite apparent in vitro susceptibility of some BLNAR strains.^{167 169} This should be considered when treating infections that may involve these strains (e.g., respiratory tract infections, AOM).^{167 169}

Efficacy of extended-release tablets in the treatment of bronchitis known, suspected, or potentially caused by β-lactamase-producing H. influenzae has not been established.¹⁶⁸

Sensitivity Reactions

Hypersensitivity Reactions

Hypersensitivity reactions such as anaphylaxis, angioedema, serum sickness-like reactions, Stevens-Johnson syndrome, and toxic epidermal necrolysis have been reported.^{167 168 169}

If an allergic reaction occurs, discontinue cefaclor and institute appropriate therapy as indicated (e.g., epinephrine, corticosteroids, and maintenance of an adequate airway and oxygen).^{167 168 169}

Cross-hypersensitivity

Partial cross-hypersensitivity among cephalosporins and other β-lactam antibiotics, including penicillins and cephamycins.^{167 168 169 a}

Prior to initiation of therapy, make careful inquiry concerning previous hypersensitivity reactions to cephalosporins, penicillins, or other drugs.^{167 168 169 a} Cautious use recommended in individuals hypersensitive to penicillins:^{167 168 169 a} avoid use in those who have had an immediate-type (anaphylactic) hypersensitivity reaction and administer with caution in those who have had a delayed-type (e.g., rash, fever, eosinophilia) reaction.^a

General Precautions

Selection and Use of Anti-infectives

To reduce development of drug-resistant bacteria and maintain effectiveness of cefaclor and other antibacterials, use only for treatment or prevention of infections proven or strongly suspected to be caused by susceptible bacteria.^{167 168 169}

When selecting or modifying anti-infective therapy, use results of culture and in vitro susceptibility testing.^{167 168 169} In the absence of such data, consider local epidemiology and susceptibility patterns when selecting anti-infectives for empiric therapy.^{167 168 169}

History of GI Disease

Use cephalosporins with caution in patients with a history of GI disease, particularly colitis.^{167 169} (See Superinfection/Clostridium difficile-associated Diarrhea and Colitis under Cautions.)

Specific Populations

Pregnancy

Category B.^{167 168 169}

Lactation

Distributed into milk; use with caution.^{167 168 169}

Pediatric Use

Capsules and oral suspension: Safety and efficacy not established in infants <1 month of age.^{167 169}

Extended-release tablets: Safety and efficacy not established in children <16 years of age.¹⁶⁸

Geriatric Use

Safety and efficacy in geriatric adults similar to that in younger adults.^{167 168 169}

Substantially eliminated by kidneys; consider monitoring renal function since geriatric patients more likely to have decreased renal function.^{167 169}

Renal Impairment

Close clinical observation and appropriate laboratory tests recommended in patients with moderate or severe renal impairment.^{167 169} Use with caution in those with markedly impaired renal function.^{167 169} (See Renal Impairment under Dosage and Administration.)

Common Adverse Effects

Diarrhea, genital pruritus or vaginitis, headache, nausea, vomiting, rash.^{123 125 127 129 130 132 153 167 168 169}

Drug Interactions

Specific Drugs and Laboratory Tests

Cefaclor Pharmacokinetics

Absorption

Bioavailability

Well absorbed from GI tract following oral administration.^{167 168 169} Peak plasma concentrations attained within 0.5–1 hour with conventional preparations¹⁶⁷ and 1.5–2.7 hours with extended-release tablets.¹⁶⁸

Food

Peak serum concentrations are lower and attained later when cefaclor capsules are administrated with food, but total amount of drug absorbed is unchanged.^{167 107 108}

When extended-release tablets are administered with food, the extent of absorption and peak plasma concentrations of the drug are increased.¹⁶⁸

Distribution

Extent

Cephalosporins are widely distributed into tissues and fluids.^a

Distributed into milk in low concentrations.^{167 168 169}

Plasma Protein Binding

25%.^a

Elimination

Metabolism

Not appreciably metabolized.^a

Elimination Route

Excreted unchanged in urine.^{167 169} About 60–85% is excreted unchanged in urine within 8 hours; majority is excreted during the first 2 hours.^{167 169}

Half-life

0.6–1 hour in adults with normal renal function.^{167 168 169}

Special Populations

Renal impairment decreases clearance of cefaclor.¹⁶⁷ Serum half-life is 2.3–2.8 hours in anuric patients.^{167 169}

Stability

Storage

Oral

Capsules

20–25°C; protect from moisture.¹⁶⁷

For Suspension

20–25°C.¹⁶⁹ After reconstitution, store suspension in tight container in the refrigerator; discard after 14 days.¹⁶⁹

Extended-release Tablets

20–25°C.¹⁶⁸

Actions and Spectrum

• Second generation cephalosporin active against some gram-negative bacteria that generally are resistant to first generation cephalosporins, but has a narrower spectrum of activity than third generation cephalosporins.^a Less active against gram-negative bacteria than some other second generation cephalosporins.^a

• Usually bactericidal.^{167 168 169}

• Like other β-lactam antibiotics, antibacterial activity results from inhibition of bacterial cell wall synthesis.^{167 168 169 a}

• In vitro spectrum of activity includes many gram-positive aerobic bacteria, some gram-negative aerobic bacteria, and a few anaerobic bacteria; inactive against fungi and viruses.^{167 168 169 a}

• Gram-positive aerobes: active in vitro and in clinical infections against staphylococci (including coagulase-positive, coagulase-negative, and penicillinase producing strains), Streptococcus pneumoniae, and S. pyogenes (group A β-hemolytic streptococci).^{167 168 169} Enterococci (e.g., Enterococcus faecalis) and methicillin-resistant (oxacillin-resistant) staphylococci are resistant.^{167 168 169 a}

• Gram-negative aerobes: active in vitro and in clinical infections against H. influenzae (except BLNAR strains), Moraxella catarrhalis (including β-lactamase producing strains), Escherichia coli, Klebsiella, and Proteus mirabilis.^{167 168 169} Also active in vitro against H. parainfluenzae, Citrobacter diversus, and Neisseria gonorrhoeae. Inactive against Acinetobacter, Enterobacter, Morganella morganii, Proteus vulgaris, Providencia, Pseudomonas, and Serratia.^{167 168 169}

• Anaerobes: active in vitro against Bacteroides (excluding B. fragilis), Peptococcus niger, Peptostreptococcus, and Propionibacterium acnes.^{167 168 169}

• Strains of staphylococci resistant to penicillinase-resistant penicillins (methicillin-resistant [oxacillin-resistant] staphylococci) should be considered resistant to cefixime, although results of in vitro susceptibility tests may indicate susceptibility.¹⁰⁵ In addition, BLNAR strains of H. influenzae should be considered resistant to cefaclor although results of in vitro susceptibility tests may indicate susceptibility.^{105 167 169}

Advice to Patients

• Advise patients that antibacterials (including cefaclor) should only be used to treat bacterial infections and not used to treat viral infections (e.g., the common cold).^{167 168 169}

• Importance of completing full course of therapy, even if feeling better after a few days.^{167 168 169}

• Advise patients that skipping doses or not completing the full course of therapy may decrease effectiveness and increase the likelihood that bacteria will develop resistance and will not be treatable with cefaclor or other antibacterials in the future.^{167 168 169}

• When cefaclor extended-release tablets used, advise patients that the tablets should not be cut, crushed, or chewed and should be taken with a meal or within 1 hour of eating.¹⁶⁸

• Advise patients that diarrhea is a common problem caused by anti-infectives and usually ends when the drug is discontinued.^{168 169} Importance of contacting a clinician if watery and bloody stools (with or without stomach cramps and fever) occur during or as late as 2 months or longer after the last dose.^{168 169}

• Importance of discontinuing cefaclor and informing clinician if an allergic reaction occurs.^{167 168 169}

• Importance of informing clinicians of existing or contemplated therapy, including prescription and OTC drugs.^{167 168 169}

• Importance of informing patients of other important precautionary information.^{167 168 169} (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

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