indication

For the treatment of the respiratory, skin, soft tissue, and ENT infections caused by H. influenzae (including b-lactamase producing strains), H. parainfluenzae (including b-lactamase producing strains), S. pneumoniae (penicillin-susceptible strains), S. pyogenes, S. aureus (including b-lactamase producing strains), and M. catarrhalis.

pharmacology

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.

mechanism of action

As with other cephalosporins, bactericidal activity of cefdinir results from inhibition of cell wall synthesis by acting on penicillin binding proteins (PBPs).

toxicity

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.

biotransformation

Cefdinir is not appreciably metabolized. Activity is primarily due to parent drug.

absorption

Maximal plasma cefdinir concentrations occur 2 to 4 hours postdose following capsule or suspension administration. Estimated bioavailability of cefdinir capsules is 21% following administration of a 300 mg capsule dose, and 16% following administration of a 600 mg capsule dose. Estimated absolute bioavailability of cefdinir suspension is 25%. Absorption is reduced by approximately 15% when administered with a high fat meal.

half life

1.7 ± 0.6 hours

route of elimination

Cefdinir is not appreciably metabolized. Cefdinir is eliminated principally via renal excretion with a mean plasma elimination half-life (t½) of 1.7 (±0.6) hours.