Cephalexin, like the penicillins, is a beta-lactam antibiotic. By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, it inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins; it is possible that cephalexin interferes with an autolysin inhibitor.
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.
No appreciable biotransformation in the liver (90% of the drug is excreted unchanged in the urine).
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.