As with other cephalosporins, bactericidal activity of cefdinir results from inhibition of cell wall synthesis by acting on penicillin binding proteins (PBPs).
Cefdinir is a third generation cephalosporin with a broad spectrum of activity against enteric gram-negative rods. Cefdinir is stable in the presence of some, but not all, b-lactamase enzymes. As a result, many organisms resistant to penicillins and some cephalosporins are susceptible to cefdinir. Cephalosporins work the same way as penicillins: they interfere with the peptidoglycan synthesis of the bacterial wall by inhibiting the final transpeptidation needed for the cross-links. This effect is bactericidal.
Cefdinir is not appreciably metabolized. Activity is primarily due to parent drug.
Information on cefdinir overdosage in humans is not available. In acute rodent toxicity studies, a single oral 5600-mg/kg dose produced no adverse effects. Toxic signs and symptoms following overdosage with other b-lactam antibiotics have included nausea, vomiting, epigastric distress, diarrhea, and convulsions.