Pseudomembranous colitis and Clostridium difficile have been reported with use of cefalexin.Signs and symptoms of an allergic reaction include rash, itching, swelling, trouble breathing, or red, blistered, swollen, or peeling skin. Overall, cefalexin allergy occurs in less than 0.1% of patients, but it is seen in 1% to 10% of patients with a penicillin allergy. Interactions
Like other β-lactam antibiotics, renal excretion of cefalexin is delayed by probenecid. Alcohol consumption reduces the rate at which it is absorbed. Cefalexin also interacts with metformin, an antidiabetic drug, and this can lead to higher concentrations of metformin in the body. Histamine H2 receptor antagonists like cimetidine and ranitidine may reduce the efficacy of cefalexin by delaying its absorption and altering its antimicrobial pharmacodynamics. Pharmacology
Mechanism of action
Cefalexin is a beta-lactam antibiotic of the cephalosporin family. It is bactericidal and acts by inhibiting synthesis of the peptidoglycan layer of the bacterial cell wall. As cefalexin closely resembles d-alanyl-d-alanine, an amino acid ending on the peptidoglycan layer of the cell wall, it is able to irreversibly bind to the active site of PBP, which is essential for the synthesis of the cell wall. It is most active against gram-positive cocci, and has moderate activity against some gram-negative bacilli. However, some bacterial cells have the enzyme β-lactamase, which hydrolyzes the beta-lactam ring, rendering the drug inactive. This contributes to antibacterial resistance towards cefalexin. Pharmacokinetics
Cefalexin is rapidly and almost completely absorbed from the gastrointestinal tract with oral administration.
Interstitial granulomatous dermatitis with arthritis (IGDA) or Ackerman dermatitis syndrome is a skin condition that most commonly presents with symmetrical round-to-oval red or violet plaques on the flanks, armpits, inner thighs, and lower abdomen. See also
Skin lesion

References


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