Action

Interferes with bacterial cell-wall synthesis, causing cell to rupture and die

Availability

Capsules: 250 mg, 500 mg

Oral suspension: 125 mg/5 ml, 187 mg/5 ml, 250 mg/5 ml, 375 mg/5 ml

Tablets (extended-release): 500 mg

Indications and dosages

➣ Uncomplicated skin infections caused by Staphylococcus aureus

Adults and children ages 16 and older: 375 mg P.O. (extended-release tablet) q 12 hours for 7 to 10 days

➣ Pharyngitis and tonsillitis not caused by Haemophilus influenzae

Adults and children ages 16 and older: 375 mg P.O. (extended-release tablet) q 12 hours for 10 days

➣ Chronic bronchitis and acute bronchitis not caused by H. influenzae

Adults and children ages 16 and older: 500 mg P.O. (extended-release tablet) q 12 hours for 7 days

➣ Otitis media caused by staphylococci; lower respiratory tract infections caused by H. influenzae, S. pyogenes, and S. pneumoniae; pharyngitis and tonsillitis caused by S. pyogenes; urinary tract infections caused by Klebsiella species, Escherichia coli, Proteus mirabilis, and coagulase-negative staphylococci

Adults and children ages 13 to 17: 250 mg P.O. q 8 hours. For severe infections, 500 mg P.O. q 8 hours.

Children: 20 mg/kg/day P.O. in divided doses q 8 hours. For serious infections, 40 mg/kg/day P.O. in divided doses q 8 hours. Maximum dosage is 1 g/day.

Dosage adjustment

• Renal insufficiency

• Elderly patients

Contraindications

• Hypersensitivity to cephalosporins or penicillins

Precautions

Use cautiously in:

• renal impairment, phenylketonuria

• history of GI disease (especially colitis)

• emaciated patients

• elderly patients

• pregnant or breastfeeding patients

• children.

Administration

• Obtain specimens for culture and sensitivity testing as necessary before starting therapy.

• Be aware that cross-sensitivity to penicillins may occur.

• Give extended-release tablets with food to enhance absorption.

• Don't give antacids within 2 hours of extended-release form.

Adverse reactions

CNS: headache, lethargy, paresthesia, syncope, seizures

CV: hypotension, palpitations, chest pain, vasodilation

EENT: hearing loss

GI: nausea, vomiting, diarrhea, abdominal cramps, oral candidiasis, pseudomembranous colitis

GU: vaginal candidiasis, nephrotoxicity

Hematologic: lymphocytosis, eosinophilia, bleeding tendency, hemolytic anemia, hypoprothrombinemia, neutropenia, thrombocytopenia, agranulocytosis, bone marrow depression

Hepatic: hepatic failure, hepatomegaly

Musculoskeletal: arthralgia

Respiratory: dyspnea

Skin: urticaria, maculopapular or erythematous rash

Other: chills, fever, superinfection, anaphylaxis, serum sickness

Interactions

Drug-drug. Aminoglycosides, loop diuretics: increased risk of nephrotoxicity

Antacids: decreased absorption of extended-release cefaclor tablets

Chloramphenicol: antagonistic effect

Probenecid: decreased excretion and increased blood level of cefaclor

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, blood urea nitrogen, creatinine, eosinophils, gamma-glutamyltransferase, lactate dehydrogenase: increased levels
Coombs' test, urinary 17-ketosteroids, nonenzyme-based urine glucose tests (such as Clinitest): false-positive results

Hemoglobin, platelets, white blood cells: decreased values

Patient monitoring

• Assess CBC and kidney and liver function test results.

• With long-term therapy, obtain monthly Coombs' test.

• Monitor for signs and symptoms of superinfection and other serious adverse reactions.

Patient teaching

• Instruct patient to take drug with food or milk to reduce GI upset.

• Advise patient to complete entire course of therapy even if he feels better.

• Tell patient to report signs and symptoms of allergic response and other adverse reactions, such as rash, easy bruising, bleeding, severe GI problems, or difficulty breathing.

• Instruct patient to avoid taking antacids within 2 hours of extended-release cefaclor.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.