cephalexin monohydrate
Pregnancy Risk Category B
How supplied
cephalexin hydrochloride
Tablets: 500 mg
cephalexin monohydrate
Tablets: 250 mg, 500 mg, 1 g
Capsules: 250 mg, 500 mg
Oral suspension: 125 mg/5 ml, 250 mg/5 ml
Action
A first-generation cephalosporin that inhibits cell-wall synthesis, promoting osmotic instability; usually bactericidal.
Indications & dosage
Respiratory tract, GI tract, skin, soft-tissue, bone, and joint infections and otitis media due to Escherichia coli and other coliform bacteria, group A beta-hemolytic streptococci, Klebsiella, Proteus mirabilis, Streptococcus pneumoniae, and staphylococci-
Adults: 250 mg to 1 g P.O. q 6 hours or 500 mg q 12 hours. Maximum 4 g daily.
Children: 6 to 12 mg/kg P.O. q 6 hours (monohydrate only). Maximum 25 mg/kg q 6 hours.
Adjust-a-dose: For adults with impaired renal function, initial dose is the same. Recommended subsequent dosing for creatinine clearance below 5 ml/minute, 250 mg P.O. q 12 to 24 hours; for creatinine clearance of 5 to 10 ml/minute, 250 mg P.O. q 12 hours; and for creatinine clearance of 11 to 40 ml/minute, 500 mg P.O. q 8 to 12 hours.
Adverse reactions
CNS: dizziness, headache, fatigue, agitation, confusion, hallucinations.
GI: pseudomembranous colitis, nausea, anorexia, vomiting, diarrhea, gastritis, glossitis, dyspepsia, abdominal pain, anal pruritus, tenesmus, oral candidiasis.
GU: genital pruritus, candidiasis, vaginitis, interstitial nephritis.
Hematologic: neutropenia, eosinophilia, anemia, thrombocytopenia.
Hepatic: transient increases in liver enzymes.
Musculoskeletal: arthritis, arthralgia, joint pain.
Skin: maculopapular and erythematous rashes, urticaria.
Other: hypersensitivity reactions, serum sickness, anaphylaxis.
Interactions
Drug-drug. Probenecid: may increase blood levels of cephalosporins. May be used for this effect.
Effects on diagnostic tests
Cephalexin causes false-positive results in urine glucose tests using cupric sulfate (Benedict's reagent or Clinitest); use glucose oxidase tests (Diastix or Chemstrip uG) instead. Drug also causes false elevations in serum or urine creatinine levels in tests using Jaffé's reaction. Positive Coombs' test results occur in about 3% of patients taking cephalexin.
Contraindications
Contraindicated in patients with hypersensitivity to cephalosporins.
Nursing considerations
Patient teaching
*Liquid contains alcohol. **May contain tartrazine. †Canada ‡Australia §U.K. OTCOver the counter
Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE-THREATENING