Cefdinir
Prescription ·Exploratory record · not publication-reviewed ·Updated July 13, 2026
Cefdinir is a third-generation oral cephalosporin antibiotic used to treat mild to moderate bacterial infections including acute bacterial sinusitis, acute otitis media, pharyngitis/tonsillitis, community-acquired pneumonia, acute exacerbations of chronic bronchitis, and uncomplicated skin infections. It provides broad activity against many gram-positive and gram-negative organisms by interfering with bacterial cell wall synthesis. A clinically important feature is that iron-containing products and many antacids markedly reduce its absorption.
Exploratory record, not a reviewed medical publication.
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What the research says.
A quick, data-only summary. The full evidence, dosing, and sources are below.
Cefdinir is a third-generation oral cephalosporin antibiotic used to treat mild to moderate bacterial infections including acute bacterial sinusitis, acute otitis media, pharyngitis/tonsillitis, community-acquired pneumonia, acute exacerbations of chronic bronchitis, and uncomplicated skin infections. NutriStack rates the supporting evidence as strong. Common adult dosing is Adults and adolescents: 300 mg orally every 12 hours, or 600 mg once daily, for 5 to 10 days depending on the infection. Pediatric (6 months to 12 years): 7 mg/kg every 12 hours or 14 mg/kg once daily (max 600 mg/day). Dose reduction is required in significant renal impairment (creatinine clearance below 30 mL/min)., though a prescriber sets the actual dose. With long-term use it can deplete vitamin k, iron. This profile indexes 3 sources.
The bottom line
Evidence rating strong. Most-documented uses: acute bacterial sinusitis (maxillary sinusitis), acute otitis media (middle ear infection), acute exacerbation of chronic bronchitis. 3 sources indexed (2004–2019), with 0 interaction records on file.
How it works, mechanistically.
Core mechanism
Cefdinir is a beta-lactam antibiotic that exerts its bactericidal effect by binding to penicillin-binding proteins (PBPs) located in the bacterial cell wall. By inhibiting these enzymes, it blocks the final transpeptidation step of peptidoglycan cross-linking, weakening the cell wall and leading to osmotic lysis and bacterial death. As a third-generation cephalosporin it is relatively stable against many bacterial beta-lactamases, giving it expanded gram-negative coverage compared with earlier-generation agents while retaining useful activity against common gram-positive pathogens such as streptococci and methicillin-susceptible staphylococci.1,2
Dosing & protocol.
Cefdinir may be taken with or without food. However, iron supplements, iron-fortified foods or formula, and aluminum- or magnesium-containing antacids substantially reduce absorption by forming insoluble complexes; separate cefdinir from these products by at least 2 hours. Co-administration with iron can also turn the stool reddish.2
What it depletes.
Nutrients this medication can lower over time, and what to replace.
Vitamin K
MildLike other broad-spectrum cephalosporins, cefdinir suppresses gut bacteria that synthesize menaquinone (vitamin K2). Reduced bacterial vitamin K production can lower vitamin K status, an effect most relevant during prolonged courses or in patients with poor dietary intake. (Cefdinir lacks the N-methylthiotetrazole side chain associated with the strongest cephalosporin-induced hypoprothrombinemia, so the risk is lower than with agents such as cefoperazone or cefamandole.)
Iron
ModerateCefdinir is not depleted by iron, but the two form a clinically important interaction: cefdinir chelates ferrous iron in the gut to produce a non-absorbable insoluble complex. Concurrent iron supplements or iron-fortified foods markedly reduce cefdinir absorption (and the complex can cause reddish stools), while the binding can also reduce the amount of supplemental iron available for absorption. Separating doses preserves both. This is included as a clinically significant nutrient-drug interaction rather than a true depletion of body iron stores.
Full safety detail.
Side effects
- Diarrhea
- Nausea
- Abdominal pain
- Vaginal candidiasis (yeast infection)
- Headache
- Rash
- Reddish stool when taken with iron-containing products
- Clostridioides difficile-associated diarrhea (uncommon but serious)
Contraindications
- Known hypersensitivity to cefdinir or other cephalosporins1,2
- History of severe (anaphylactic) reaction to penicillins or other beta-lactams (use caution due to cross-reactivity)
- Caution in patients with significant renal impairment (dose adjustment required)2
- Caution in patients with a history of colitis or gastrointestinal disease
Sources, by evidence tier.
Numbered references. Citations throughout the page link here.
Reviews & position papers
1- 1Cefdinir: a review of its use in the management of mild-to-moderate bacterial infectionsPerry CM, Scott LJ · Drugs · 2004
Cefdinir achieved high clinical cure rates in sinusitis, otitis media, pharyngitis, bronchitis, and skin infections with a tolerability profile typical of cephalosporins.
Reference material
2- 2Omnicef (cefdinir) capsules and oral suspension - US prescribing informationAbbVie / Abbott Laboratories · FDA Prescribing Information · 2019
Approved for acute sinusitis, otitis media, pharyngitis/tonsillitis, community-acquired pneumonia, acute exacerbation of chronic bronchitis, and uncomplicated skin infections; renal dose adjustment needed below CrCl 30 mL/min.
- 3Effect of iron and antacids on cefdinir oral bioavailabilityManufacturer pharmacokinetic data · FDA Prescribing Information (Drug Interactions) · 2019
Iron supplements reduced cefdinir absorption by about 80% and aluminum/magnesium antacids by about 40%; dosing separation of 2 hours is recommended.
Common questions.
Quick answers about Cefdinir, drawn from the data on this page.
What is Cefdinir?
Cefdinir is a third-generation oral cephalosporin antibiotic used to treat mild to moderate bacterial infections including acute bacterial sinusitis, acute otitis media, pharyngitis/tonsillitis, community-acquired pneumonia, acute exacerbations of chronic bronchitis, and uncomplicated skin infections. It provides broad activity against many gram-positive and gram-negative organisms by interfering with bacterial cell wall synthesis. A clinically important feature is that iron-containing products and many antacids markedly reduce its absorption.
What is Cefdinir used for?
Commonly cited benefits of Cefdinir include: Acute bacterial sinusitis (maxillary sinusitis); Acute otitis media (middle ear infection); Acute exacerbation of chronic bronchitis; Community-acquired pneumonia; Pharyngitis and tonsillitis. NutriStack rates the overall evidence as strong.
What is a typical dose of Cefdinir?
A typical adult dose of Cefdinir is Adults and adolescents: 300 mg orally every 12 hours, or 600 mg once daily, for 5 to 10 days depending on the infection. Pediatric (6 months to 12 years): 7 mg/kg every 12 hours or 14 mg/kg once daily (max 600 mg/day). Dose reduction is required in significant renal impairment (creatinine clearance below 30 mL/min).. The commonly recommended form is Oral capsule (300 mg) or oral powder for suspension; may be taken with or without food.. These are general ranges, not personalized advice; confirm the right dose with a clinician.
What are the side effects of Cefdinir?
Reported side effects include diarrhea, nausea, abdominal pain, vaginal candidiasis (yeast infection), headache, rash. This is educational information; check with a healthcare professional before use.
How strong is the evidence for Cefdinir?
NutriStack rates this as Strong, meaning multiple high-quality meta-analyses or systematic reviews converge on the same finding. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.
Use this with your stack
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