Cefaclor  (PDF Version)


Antibiotic Class:

Second-Generation Cephalosporin (true 2nd generation cephalosporin)


Antimicrobial Spectrum:

Staphylococcus aureus (methicillin susceptible), Coagulase negative Staphylococci, Streptococcus pneumoniae (penicillin susceptible), Streptococcus spp. Haemophilus influenzae, Moraxella catarrhalis, Neisseria meningitides, Neisseria gonorrhoeae


Mechanism of Action:

Cephalosporins exert bactericidal activity by interfering with bacterial cell wall synthesis and inhibiting cross-linking of the peptidoglycan. The cephalosporins are also thought to play a role in the activation of bacterical cell autolysins which may contribute to bacterial cell lysis.



Cephalosporins exhibit time-dependent killing (T > MIC)



Dose of 500mg: Cmax: 17.3 mcg/L; Tmax: 0.7 hours; Half-life: 0.6 hours; Table 10


Adverse Effects:

Hypersensitivity: Maculopapular rash, Urticaria, Pruritis, Anaphylaxis/angioedema, eosinophilia

Hematologic: Neutropenia, Leukopenia, Thrombocytopenia

GI: Diarrhea, C. difficile disease

Renal: Interstitial nephritis

Table 14



PO: 250mg, 500mg capsules

       Powder for Suspension: 125mg/5mL, 187mg/5mL, 250 mg/5mL, 375mg/5mL

       Chewable tablets: 125mg, 187mg, 250mg, 375mg

       Extended release tablets: 375mg, 500mg


Dosing in adults:

Acute exacerbation of chronic bronchitis: 500 mg extendedrelease tablets PO q12h x 7 days

Acute otitis media: 250mg to 500mg tablets PO q8h

Lower respiratory tract infection: 250mg to 500mg tablets PO q8h

Urinary tract infection: 250mg to 500mg tablets PO q8h


Dosing in pediatrics:

20-40mg/kg divided PO q8h


Disease state based dosing:

Renal failure:  Caution with markedly impaired renal function; dose adjustment for moderate to severe renal impairment not usually recommended

Hepatic failure:  No dosing changes recommended at this time.



Precautions:  Hypersensitivity to penicillins, renal impairment


Drug Interactions:

Live Typhoid Vaccine: decreased immunological response to the typhoid vaccine



Category B: No evidence of risk in humans but studies inadequate.


Monitoring Requirements:

Therapeutic:  Culture and sensitivities, serum levels, signs and symptoms of infection, white blood cell count

Toxic:  Urinalysis, BUN, SCr, AST and ALT, skin rash, Neutropenia and leukopenia, Prothrombin time in patients with renal or hepatic impairment or poor nutritional state, as well as patients receiving a protracted course of antimicrobial therapy, and patients previously stabilized on anticoagulant therapy.


Brand names/Manufacturer:  Ceclor/Eli Lilly; Ceclor CD/Dura Pharmaceuticals; Cefaclor Extended Release/Ivax Pharmaceuticals