A semisynthetic cephalosporin antibiotic with antimicrobial activity similar to that of cephaloridine or cephalothin, but somewhat less potent. It is effective against both gram-positive and gram-negative organisms. [PubChem]
Indication
For the treatment of respiratory tract infections caused by Streptococcus pneumoniae and Streptococcus pyogenes; otitis media due to Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Streptococcus pyogenes, and Moraxella catarrhalis; skin and skin structure infections caused by Staphylococcus aureus and/or Streptococcus pyogenes; bone infections caused by Staphylococcus aureus and/or Proteus mirabilis; genitourinary tract infections, including acute prostatitis, caused by Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae.
Pharmacology
Cephalexin (also called Cefalexin) is a first generation cephalosporin antibiotic. It is one of the most widely prescribed antibiotics, often used for the treatment of superficial infections that result as complications of minor wounds or lacerations. It is effective against most gram-positive bacteria.
Toxicity
Symptoms of overdose include blood in the urine, diarrhea, nausea, upper abdominal pain, and vomiting. The oral median lethal dose of cephalexin in rats is >5000 mg/kg.
Affected Organisms
Enteric bacteria and other eubacteria
Biotransformation
No appreciable biotransformation in the liver (90% of the drug is excreted unchanged in the urine).
Absorption
Well absorbed from the gastrointestinal tract
Half Life
1 hour
Protein Binding
14%
Elimination
Cephalexin is excreted in the urine by glomerular filtration and tubular secretion. Studies showed that over 90% of the drug was excreted unchanged in the urine within 8 hours.