Uses
Acute Otitis Media (AOM)
Treatment of AOM caused by susceptible S. pneumoniae, Haemophilus influenzae, M. catarrhalis, or staphylococci or streptococci.
Pharyngitis and Tonsillitis
Treatment of pharyngitis and tonsillitis caused by Streptococcus pyogenes (group A β-hemolytic streptococci). Generally effective in eradicating S. pyogenes from the nasopharynx, but efficacy in prevention of subsequent rheumatic fever has not been established to date.
CDC, AAP, IDSA, AHA, and others recommend oral penicillin V or IM penicillin G benzathine as treatments of choice; oral cephalosporins and oral macrolides considered alternatives. Amoxicillin sometimes used instead of penicillin V, especially for young children.
Bone and Joint Infections
Treatment of bone and joint infections caused by susceptible staphylococci or Proteus mirabilis.
Respiratory Tract Infections
Treatment of mild to moderate respiratory tract infections caused by Streptococcus pneumoniae.
Skin and Skin Structure Infections
Treatment of mild to moderate skin and skin structure infections caused by susceptible staphylococci or streptococci.
Urinary Tract Infections (UTIs)
Treatment of mild to moderate UTIs, including acute prostatitis, caused by susceptible Escherichia coli, Klebsiella pneumoniae, or P. mirabilis.
Prevention of Bacterial Endocarditis
Alternative for prevention of α-hemolytic (viridans group) streptococcal endocarditis† in penicillin-allergic individuals undergoing certain dental or upper respiratory tract procedures who have cardiac conditions that put them at highest risk. Should not be used in those with immediate-type penicillin hypersensitivity (see Cross-hypersensitivity under Cautions).
When selecting anti-infectives for prophylaxis of bacterial endocarditis, consult most recent AHA recommendations for specific information on which cardiac conditions are associated with highest risk of endocarditis and which procedures require prophylaxis.
Dosage and Administration
Administration
Oral Administration
Administer orally without regard to meals.
Reconstitution
Reconstitute oral suspension at time of dispensing by adding the amount of water specified on the container.
Reconstituted suspensions contain 125 or 250 mg of cephalexin/5 mL.
Shake oral suspension well prior to administration of each dose.
Dosage
Available as cephalexin monohydrate; dosage expressed in terms of cephalexin.
Pediatric Patients
General Pediatric Dosage
Oral
25–50 mg/kg daily in divided doses. Manufacturers state that these dosages may be doubled for severe infections; AAP states that cephalexin is inappropriate for severe infections.
Acute Otitis Media (AOM)
Oral
75–100 mg/kg daily in 4 divided doses.
Pharyngitis and Tonsillitis
Oral
25–50 mg/kg daily in 3–4 equally divided doses for ≥10 days. Daily dosage may be given in divided doses every 12 hours in those >1 year of age.
Children >15 years of age: 500 mg every 12 hours for ≥10 days.
Bone and Joint Infections
Oral
25–50 mg/kg daily in 3–4 equally divided doses for mild to moderate infections.
Manufacturers state dosage may be doubled for severe infections; AAP states the drug is inappropriate for severe infections.
Respiratory Tract Infections
Oral
25–50 mg/kg daily in 3–4 equally divided doses for mild to moderate infections.
Manufacturers state dosage may be doubled for severe infections; AAP states the drug is inappropriate for severe infections.
Skin and Skin Structure Infections
Oral
25–50 mg/kg daily in divided doses every 12 hours for mild to moderate infections.
Children >15 years of age: 500 mg every 12 hours for mild to moderate infections.
Manufacturers state dosage may be doubled for severe infections; AAP states the drug is inappropriate for severe infections.
Urinary Tract Infections (UTIs)
Oral
25–50 mg/kg daily in 3–4 equally divided doses for mild to moderate infections.
Children >15 years of age with uncomplicated cystitis: 500 mg every 12 hours for 7–14 days.
Manufacturers state dosage may be doubled for severe infections; AAP states the drug is inappropriate for severe infections.
Prevention of Bacterial Endocarditis
Patients Undergoing Certain Dental or Upper Respiratory Tract Procedures
Oral
50 mg/kg (up to 2 g) as a single dose given 0.5–1 hour prior to the procedure.†
Adults
General Adult Dosage
Oral
Usual dosage ranges from 1–4 g daily given in divided doses. If dosage >4 g daily is required, consider initial therapy with a parenteral cephalosporin.
Acute Otitis Media (AOM)
Oral
250 mg every 6 hours. Higher dosage may be needed for severe infections or those caused by less susceptible bacteria.
Pharyngitis and Tonsillitis
Oral
500 mg every 12 hours for ≥10 days.
Bone and Joint Infections
Oral
250 mg every 6 hours. Higher dosage may be needed for severe infections or those caused by less susceptible bacteria.
Respiratory Tract Infections
Oral
250 mg every 6 hours for mild to moderate infections. Higher dosage may be needed for more severe infections or those caused by less susceptible bacteria.
Skin and Skin Structure Infections
Oral
500 mg every 12 hours for mild to moderate infections. Higher dosage may be needed for severe infections or those caused by less susceptible bacteria.
Urinary Tract Infections (UTIs)
Oral
500 mg every 12 hours for 7–14 days for mild to moderate infections. Higher dosage may be needed for severe infections or those caused by less susceptible bacteria.
Prevention of Bacterial Endocarditis
Patients Undergoing Certain Dental or Upper Respiratory Tract Procedures
Oral
2 g as a single dose given 0.5–1 hour prior to the procedure.†
Special Populations
Dosage in Renal Impairment
Use with caution in patients with markedly impaired renal function; close clinical observation and appropriate laboratory tests recommended because safe dosage may be lower than usual dosages.
Some clinicians suggest that the usual adult dosage be used for the initial dose. Then, for subsequent doses, use 500 mg every 8–12 hours if Clcr 11–40 mL/minute, 250 mg every 12 hours if Clcr 5–10 mL/minute, or 250 mg every 12–24 hours if Clcr <5 mL/minute.
Geriatric Patients
Cautious dosage selection because of age-related decreases in renal function. (See Renal Impairment under Dosage and Administration.)
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