cephalexin(redirected from Cefalexin)
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Pharmacologic class: First-generation cephalosporin
Therapeutic class: Anti-infective
Pregnancy risk category B
Interferes with bacterial cell-wall synthesis, causing cell to rupture and die. Active against many gram-positive bacteria; shows limited activity against gram-negative bacteria.
Capsules: 250 mg, 500 mg, 750 mg
Oral suspension: 125 mg/5 ml, 250 mg/5 ml
Tablets: 250 mg, 500 mg
Indications and dosages
➣ Respiratory tract infections caused by streptococci; skin and skin-structure infections caused by methicillin-sensitive staphylococci and streptococci; bone infections caused by methicillin-sensitive staphylococci or Proteus mirabilis; genitourinary infections caused by Escherichia coli, P. mirabilis, and Klebsiella species; Haemophilus influenzae, methicillin-sensitive staphylococcal, streptococcal, and Moraxella catarrhalis infections
Adults: 1 to 4 g P.O. daily in divided doses (usually 250 mg P.O. q 6 hours). For uncomplicated cystitis, skin and soft-tissue infections, and streptococcal pharyngitis, 500 mg P.O. q 12 hours.
Children: 25 to 50 mg/kg/day P.O. in divided doses
➣ Otitis media caused by S. pneumoniae
Children: 75 to 100 mg/kg/day P.O. in four divided doses
• Renal impairment
• Hypersensitivity to cephalosporins or penicillin
Use cautiously in:
• renal impairment, phenylketonuria
• history of GI disease
• debilitated or emaciated patients
• elderly patients
• pregnant or breastfeeding patients.
• Give with or without food.
• Refrigerate oral suspension.
CNS: fever, headache, lethargy, paresthesia, syncope, seizures
CV: edema, hypotension, vasodilation, palpitations, chest pain
EENT: hearing loss
GI: nausea, vomiting, diarrhea, abdominal cramps, oral candidiasis, pseudomembranous colitis
GU: vaginal candidiasis, nephrotoxicity
Hematologic: lymphocytosis, eosinophilia, bleeding tendency, hemolytic anemia, neutropenia, thrombocytopenia, agranulocytosis, bone marrow depression
Musculoskeletal: joint pain
Skin: rash, maculopapular and erythematous urticaria
Other: superinfection, chills, pain, allergic reaction, hypersensitivity reactions including anaphylaxis, serum sickness
Drug-drug. Aminoglycosides, loop diuretics: increased risk of nephrotoxicity
Chloramphenicol: antagonistic effect
Probenecid: increased cephalexin blood level
Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, blood urea nitrogen, creatinine, eosinophils, lactate dehydrogenase, lymphocytes: increased values
Coombs' test: false-positive result (especially in neonates whose mothers received drug before delivery)
Granulocytes, neutrophils, white blood cells: decreased counts
• Assess for signs and symptoms of serious adverse reactions, including hypersensitivity, severe diarrhea, and bleeding.
• During long-term therapy, monitor CBC and liver and kidney function test results.
Instruct patient to stop taking drug and contact prescriber immediately if he develops rash or difficulty breathing.
• Tell patient to take drug with full glass of water.
• Advise patient to report severe diarrhea.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.