Brands, Medical Use, Clinical Data
- Capsules for oral administration (300mg)
- Oral suspension (125mg per 5mL solution)
Brands / Synonyms
Cefdinir (JP14/USAN); Cefdirnir; Cefzon; Cefzon (TN); CFDN; Omnicef; Omnicef (TN)
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.
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).
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.
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.
Biotrnasformation / Drug Metabolism
Cefdinir is not appreciably metabolized. Activity is primarily due to parent drug.
OMNICEF (cefdinir) is contraindicated in patients with known allergy to the cephalosporin class of
Antacids (aluminum- or magnesium-containing)
Concomitant administration of 300-mg cefdinir capsules with 30 mL Maalox® TC
suspension reduces the rate (Cmax) and extent (AUC) of absorption by approximately 40%. Time to reach
Cmax is also prolonged by 1 hour. There are no significant effects on cefdinir pharmacokinetics if the
antacid is administered 2 hours before or 2 hours after cefdinir. If antacids are required during OMNICEF therapy,
OMNICEF should be taken at least 2 hours before or after the antacid.
As with other b-lactam antibiotics, probenecid inhibits the renal excretion of cefdinir, resulting in an approximate doubling
in A.C. a 54% increase in peak cefdinir plasma levels, and a 50% prolongation in the apparent elimination
Iron Supplements and Foods Fortified With Iron
Concomitant administration of cefdinir with a therapeutic iron supplement containing 60 mg of
elemental iron (as FeSO4) or vitamins supplemented with 10 mg of elemental iron reduced extent of
absorption by 80% and 31%, respectively. If iron supplements are required during OMNICEF therapy, OMNICEF should be
taken at least 2 hours before or after the supplement.
The effect of foods highly fortified with elemental iron (primarily iron-fortified breakfast cereals)
on cefdinir absorption has not been studied.
Concomitantly administered iron-fortified infant formula (2.2 mg elemental iron/6 oz) has no
significant effect on cefdinir pharmacokinetics. Therefore, OMNICEF for Oral Suspension can be administered with
iron-fortified infant formula.
There have been rare reports of reddish stools in patients who have received cefdinir in Japan. The
reddish color is due to the formation of a nonabsorbable complex between cefdinir or its breakdown products and iron
in the gastrointestinal tract.
Drug/Laboratory Test Interactions
A false-positive reaction for ketones in the urine may occur with tests using nitroprusside, but not
with those using nitroferricyanide. The administration of cefdinir may result in a false-positive reaction for
glucose in urine using Clinitest®, Benedictís solution, or Fehling's solution. It is
recommended that glucose tests based on enzymatic glucose oxidase reactions (such as Clinistix® or
Tes-Tape®) be used. Cephalosporins are known to occasionally induce a positive direct Coombsí