Systematic (IUPAC) name
azabicyclo[4.2.0]oct-4-ene-5-carboxylic acid
Clinical data
Trade names Cefzon
Pregnancy cat.
Legal status
  • US: Rx only
Routes Oral
Pharmacokinetic data
Bioavailability 16% to 21% (dose-dependent)
Protein binding 60% to 70%
Metabolism Negligible
Half-life 1.7 ± 0.6 hours
Excretion Renal
CAS number  YesY
ATC code J01
ChemSpider  YesY
Chemical data
Formula C14H13N5O5S2 
Mol. mass 395.416 g/mol

Cefdinir is a third-generation oral cephalosporin antibiotic.

As of 2008, cefdinir, as Omnicef, was the highest-selling cephalosporin antibiotic in the United States, with more than US$585 million in retail sales of its generic versions alone.[1]

It was discovered by Fujisawa Pharmaceutical Co., Ltd. (now Astellas) and introduced in 1991 under the brand name Cefzon.[2][3] Warner-Lambert licensed this cephalosporin for marketing in US from Fujisawa.[4] Abbott obtained U.S. marketing rights to Omnicef (cefdinir) in December 1998 through an agreement with Warner-Lambert Company.[5] It was approved by FDA on Dec 4, 1997.[6] It is available in US as Omnicef by Abbott Laboratories and in India as Cednir by Abbott, Kefnir by Glenmark and Cefdiel by Ranbaxy.

Mechanism of action


Therapeutic uses of cefdinir include otitis media, soft tissue infections, and respiratory tract infections, including sinusitis, strep throat (note: no documented resistance of Group A Streptococcus to penicillin has ever been reported, and penicillin or amoxicillin is the first line treatment), 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.

Spectrum of bacterial susceptibility and resistance

Cefdinir is a broad-spectrum antibiotic and has been used to treat infections of the respiratory tract including pneumonia, sinusitis, and bronchitis. The following represents MIC susceptibility data for a few medically significant microorganisms.

  • Haemophilus influenzae: 0.05 - 4 μg/ml
  • Streptococcus pneumoniae: 0.006 - 64 μg/ml
  • Streptococcus pyogenes: ≤0.004 - 2 μg/ml


Side effects

Side effects include diarrhea, vaginal infections or inflammation, nausea, headache, and abdominal pain."[8]

Available forms

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.

"Blood" in the stool

The pediatric version of cefdinir can bind to iron in the digestive tract; in rare cases, this causes a rust or red discoloration of the stool. Blood typically appears dark brown or black in stool, and testing may confirm which is present. If the reddish stool is accompanied by abdominal pain, weight loss, diarrhea, etc., a Clostridium difficile infection caused by the antibiotic could be signified. Special caution required for pediatric dry powder; it may take longer for proper mixing.


  1. ^ "2008 Top 200 generic drugs by retail dollars"  PDF (399.4 KB). Drug Topics (May 26, 2009). Retrieved on July 24, 2009.
  2. ^ http://www.astellas.com/en/corporate/news/detail/astellas-filed-lawsuit-against.html
  3. ^ http://wenku.baidu.com/view/a2ef6330b90d6c85ec3ac6fa.html
  4. ^ http://www.elsevierbi.com/publications/the-pink-sheet/52/005/comprecin-has-excellent-chance-to-reach-us-market-this-year-dupont-prophenytoin-crosslicense-deal?p=1
  5. ^ http://www.globenewswire.com/newsarchive/mrx/pages/news_releases.html?d=94045
  6. ^ http://www.drugs.com/mtm/cefdinir.html
  7. ^ http://www.toku-e.com/Assets/MIC/Cefdinir.pdf
  8. ^ "Omnicef capsules Patient Information".  

External links

  • Medline Plus: Cefdinir