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Systematic (IUPAC) name
azabicyclo[4.2.0]oct-4-ene-5-carboxylic acid
CAS number 91832-40-5
ATC code J01DD15
PubChem 6399253
DrugBank APRD00644
Chemical data
Formula C14H13N5O5S2 
Mol. mass 395.416 g/mol
Pharmacokinetic data
Bioavailability 16% to 21% (dose-dependent)
Protein binding 60% to 70%
Metabolism Negligible
Half life 1.7 ± 0.6 hours
Excretion Renal
Therapeutic considerations
Pregnancy cat.


Legal status


Routes Oral

Cefdinir (marketed by Abbott Laboratories under the brand name Omnicef) is a semi-synthetic, broad-spectrum antibiotic in the third generation of the cephalosporin class, proven effective for common bacterial infections of the ear, sinus, throat, and skin. It was approved by the U.S. Food and Drug Administration (FDA) in December of 1997.


Mechanism of action

Main article: Cephalosporin


Therapeutic uses of cefdinir include otitis media, soft tissue infections, and respiratory tract infections, including sinusitis, strep throat, community-acquired pneumonia and acute exacerbations of bronchitis.

Susceptible organisms

Cefdinir is a bacteriocidal antibiotic. It can be used to treat infections caused by several Gram-negative and Gram-positive bacteria, including:


  • Haemophilus influenzae
  • Moraxella catarrhalis
  • Escherichia coli
  • Klebsiella spp.
  • Proteus mirabilis


  • Staphylococcus aureus
  • Streptococcus pneumoniae
  • Streptococcus pyogenes

Like most third-generation cephalosporins (except Ceftazidime), cefdinir is not an effective treatment against infections caused by Pseudomonas aeruginosa.

Side effects

According to the Omnicef website, side effects include "(...) diarrhea, vaginal infections or inflammation, nausea, headache, and abdominal pain."[1]

Available forms and dosage

  Cefdinir is administered orally. It is available as capsules and a suspension. Dosage, schedule, and duration of therapy varies according to the type of infection. For adults, the average dosage is between 300 and 600 mg per 12 or 24 hour period, for the duration of between 5 and 10 days. Average pediatric dosage is between 7 and 14 mg/kg (schedule and duration the same as adult).


"Blood" in the Stool

The pediatric version of Omnicef® can bind to iron in the digestive tract. In rare cases, this creates a discoloration of the stool to a rust or red color. Some patients may interpret this as blood in the stool, although in reality blood appears dark brown or black in the stool. A doctor's office can perform a simple stool guaiac test on the stool to confirm that it does not have blood. If you simply wait one hour, the red color will remain red, (while real blood will turn black).

On the other hand, if the reddish stool is accompanied by abdominal pain, weight loss, diarrhea, etc., it could be a C. difficile (clostridium difficile) infection caused by the antibiotic. This infection can occur as a result of taking an antibiotic. Talk to your pediatrician immediately to see if you should stop using the antibiotic.


  1. ^ Omnicef® capsules Patient Information. Abbott Laboratories (February 2004). Retrieved on 2006-11-24.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Cefdinir". A list of authors is available in Wikipedia.
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