Cefdinir
Pronunciation: sef-DIN-ir.
- Generic name
- cefdinir
- Drug class
- Third-generation cephalosporin antibiotic
- Form
- Capsule (300 mg); oral suspension (125 mg/5 mL, 250 mg/5 mL)
- Route
- Oral
- Legal status
- Prescription-only in the United States (the one market confirmed in this review)
Availability and supply rules vary by country
Trade names by country: United States
Australia: · Full directory
What cefdinir is and how it works
Cefdinir is a third-generation oral cephalosporin antibiotic used to treat a range of bacterial infections, including certain infections of the lungs, sinuses, throat/tonsils, ears, skin, and airways. Like other cephalosporins, it works by interfering with bacterial cell wall formation, causing susceptible bacteria to die. It is not effective against viral infections such as the common cold or flu. (1)
Cefdinir should only be used for infections that are proven or strongly suspected to be caused by bacteria susceptible to it. Like other cephalosporin and penicillin-class antibiotics, it carries a real risk of serious allergic reaction (including anaphylaxis) and of Clostridioides difficile-associated diarrhea, which can appear even more than two months after finishing treatment. Your prescriber will confirm whether cefdinir is appropriate for your specific infection, age, and kidney function.
Mechanism of action: how cefdinir works
Cefdinir is a third-generation cephalosporin that inhibits bacterial cell-wall synthesis by binding penicillin-binding proteins, leading to cell lysis and death in susceptible Gram-positive and Gram-negative organisms. It is stable to a number of beta-lactamase enzymes that inactivate other beta-lactam antibiotics. (1)
What cefdinir is used for
Community-acquired pneumonia
Used in adults and adolescents (13 years and older) for community-acquired pneumonia caused by susceptible bacteria. (1)
Acute exacerbations of chronic bronchitis
Used in adults and adolescents (13 years and older) for acute bacterial flare-ups of chronic bronchitis. (1)
Acute maxillary sinusitis
Used in adults and adolescents (13 years and older) for acute bacterial sinus infections. (1)
Pharyngitis and tonsillitis
Used in adults, adolescents, and children for bacterial throat/tonsil infections caused by Streptococcus pyogenes. (1)
Acute bacterial otitis media (children)
Used in pediatric patients for acute bacterial middle-ear infections. (1)
Uncomplicated skin and skin-structure infections
Used in adults, adolescents, and children for certain uncomplicated bacterial skin infections. (1)
Before taking cefdinir
Do not take / not appropriate for
- Do not take cefdinir if you have a known allergy to the cephalosporin class of antibiotics. (United States) (1)
- Tell your prescriber before starting cefdinir about any previous allergic reaction to cefdinir, other cephalosporins, penicillins, or other drugs -- cross-reactivity between penicillins and cephalosporins has been clearly documented and may occur in up to 10% of patients with a penicillin-allergy history. (United States) (1)
Tell your clinician about
- Any personal history of colitis or other bowel disease.
- Any reduced kidney function -- your dose may need to be lowered.
- Whether you are pregnant, plan to become pregnant, or are breastfeeding.
- All other medicines you take, especially antacids, iron supplements or iron-containing vitamins, and probenecid.
How to take cefdinir
- Cefdinir may be taken without regard to meals.
- Complete the full course prescribed, even if you feel better before it is finished, unless your prescriber tells you otherwise.
- If you also take an aluminum- or magnesium-containing antacid, an iron supplement, or an iron-containing vitamin, separate the dose from cefdinir by at least 2 hours -- both antacids and iron significantly reduce how much cefdinir your body absorbs.
- Reddish-colored stools can occur while taking cefdinir together with iron-containing products; this is a harmless, non-absorbable complex forming in the gut, not a sign of bleeding, but mention any concern to your prescriber or pharmacist.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1)
Missed dose
If you miss a dose, contact your prescriber or pharmacist for guidance rather than doubling your next dose. Completing the prescribed course on schedule matters for treating the infection effectively and reducing the risk of resistant bacteria.
Overdose
Seek urgent medical attention if you think too much cefdinir has been taken, or if symptoms such as severe nausea, vomiting, stomach pain, diarrhea, or seizures occur. No specific human overdose data are available; hemodialysis can remove cefdinir from the body and may be used by a clinician for a serious toxic reaction, particularly if kidney function is reduced. (1)
Side effects
Side effects and their urgency vary; report severe, persistent, or concerning symptoms.
Diarrhea
What to notice: The most common side effect, reported in about 15% of adults in clinical trials.
What to do: Usually mild; contact your prescriber if it is severe or persistent. (1)
Vaginal yeast infection (vaginal moniliasis)
What to notice: Reported in about 4% of women in clinical trials.
What to do: Contact your prescriber if symptoms are bothersome. (1)
Nausea
What to notice: A common digestive side effect.
What to do: Taking with food may help; contact your prescriber if severe. (1)
Headache
What to notice: A common side effect.
What to do: Contact your prescriber if severe or persistent. (1)
Abdominal pain
What to notice: A common digestive side effect.
What to do: Contact your prescriber if severe or persistent. (1)
Rash, dyspepsia, flatulence, vomiting, reduced appetite, constipation, dizziness, or dry mouth
What to notice: Each reported in less than 1% of patients.
What to do: Contact your prescriber if any of these are bothersome or persistent. (1)
Serious warnings
Serious allergic reaction (hypersensitivity/anaphylaxis) — emergency
Symptoms: Hives, swelling of the face/lips/tongue/throat, difficulty breathing, wheezing, or a sudden drop in blood pressure -- can occur even without a prior reaction to a cephalosporin, and cross-reactivity with penicillin allergy has been documented in up to 10% of patients with that history.
Action: Seek emergency medical help immediately. Serious acute hypersensitivity reactions may require emergency treatment with epinephrine, oxygen, IV fluids, IV antihistamines, corticosteroids, and airway management -- do not attempt to manage this yourself. (1)
Clostridioides difficile-associated diarrhea (CDAD) / colitis — high caution
Symptoms: Watery or bloody diarrhea, abdominal cramping, or fever, developing during treatment or for up to two months or more after finishing cefdinir.
Action: Contact your prescriber promptly if diarrhea develops during or after treatment, even weeks later -- do not treat it yourself with anti-diarrheal medicine before checking with your prescriber, since this can worsen some cases. (1)
Severe skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis) -- rare — emergency
Symptoms: Severe rash, blistering, or peeling skin, often with fever or mouth sores.
Action: Seek emergency medical care immediately and stop the medicine only on your prescriber's or emergency clinician's instruction. (1)
Seizures (rare, mainly in reduced kidney function without adequate dose reduction) — high caution
Symptoms: Unusual muscle twitching, confusion, or a seizure.
Action: Seek prompt medical attention. This is a recognised class effect of cephalosporins, especially when the dose has not been reduced appropriately for kidney function. (1)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Aluminum- or magnesium-containing antacids | Reduce cefdinir absorption by about 40%. | Take cefdinir at least 2 hours before or after this type of antacid. (1) |
| Iron supplements and iron-containing vitamins | A 60 mg elemental-iron supplement reduced cefdinir absorption by 80%; a 10 mg iron-containing vitamin reduced it by 31%. | Separate dosing by at least 2 hours. (1) |
| Probenecid | Inhibits the kidneys’ excretion of cefdinir, roughly doubling its blood-level exposure (AUC) and raising peak levels by 54%. | Your prescriber will factor this in if you take both. (1) |
Pregnancy, breastfeeding, kidney/liver function, age
Pregnancy
Cefdinir is FDA pregnancy Category B in the label reviewed: no adequate, well-controlled human studies exist, and it should be used in pregnancy only if clearly needed, as decided with your prescriber. (1)
Breastfeeding
In a study of single 600 mg doses, cefdinir was not detected in human breast milk, per the US label reviewed. Discuss breastfeeding with your prescriber regardless, as individual circumstances vary. (1)
Children
Approved for acute bacterial otitis media, pharyngitis/tonsillitis, and uncomplicated skin infections in pediatric patients, using an age/weight-based oral suspension dose set by the prescriber. Safety and efficacy have not been established in infants under 6 months. (1)
Elderly
No routine dose adjustment is needed based on age alone unless kidney function is markedly reduced; efficacy in clinical trials was comparable to younger adults, with a lower rate of reported adverse events. (1)
Renal_impairment
Dose must be reduced for creatinine clearance below 30 mL/min (300 mg once daily), and adjusted further for hemodialysis (300 mg every other day, with a dose after each dialysis session) -- your prescriber will confirm your kidney function before dosing. (1)
Source_ids
US-DAILYMED-CEFDINIR-2026 (1)
Monitoring
Before starting
- Confirmation the infection is bacterial and susceptible to cefdinir, not viral
- Review of prior allergic reactions to cephalosporins or penicillins
- Kidney function assessment if impairment is suspected
During treatment
- Watch for signs of an allergic reaction, especially in the first doses.
- Watch for new or worsening diarrhea during treatment and for at least two months afterward.
- Kidney function monitoring if there is pre-existing renal impairment.
Storage
Store capsules at room temperature. Oral suspension, once reconstituted, should be stored as directed on the pharmacy label and discarded after the labeled period -- ask your pharmacist for the exact discard date for your product.
Study the drug class: Cephalosporins
Professional information
Clinician-facing context only, sourced from the current US FDA prescribing information reviewed for this dossier; verify against the current full label before prescribing.
United States
Indication: Community-acquired pneumonia, acute bacterial exacerbation of chronic bronchitis, acute maxillary sinusitis, pharyngitis/tonsillitis, uncomplicated skin infections (adults/adolescents 13+); acute bacterial otitis media, pharyngitis/tonsillitis, uncomplicated skin infections (pediatric)
Dose summary: 300 mg every 12 hours (most indications) or 600 mg once daily (bronchitis, sinusitis, pharyngitis/tonsillitis), 5-10 or 10 days depending on indication. Pediatric dosing is weight-based via oral suspension.
Renal context: CrCl <30 mL/min: 300 mg once daily. Hemodialysis: 300 mg every other day, with a supplemental 300 mg dose at the end of each dialysis session (about 63% of cefdinir is removed by hemodialysis). (1)
Hepatic guidance
No specific hepatic dose adjustment is described in the source reviewed; cefdinir is primarily renally eliminated.
Overdose note
No human overdose data available; supportive care and consideration of hemodialysis (removes ~63% of cefdinir) in patients with reduced renal function. (1)
Frequently asked questions
Is cefdinir available in the US, UK, Europe, Canada, Australia, and New Zealand?
Confirmed availability in this review was limited to the United States, where generic cefdinir is currently FDA-approved and marketed (the original Omnicef brand has been discontinued). Direct searches of each other market's own regulator tool -- the UK's electronic medicines compendium and MHRA products search, Health Canada's Drug Product Database, the EMA's medicines search, TGA, and Medsafe -- did not find a confirmed current listing for cefdinir, so availability in the UK, European Union, Canada, Australia, and New Zealand is recorded as unable to verify rather than assumed. (1)
Can I take antacids or iron supplements with cefdinir?
Not at the same time. Aluminum/magnesium antacids and iron supplements (or iron-containing vitamins) both significantly reduce how much cefdinir your body absorbs. Separate the doses by at least 2 hours. Reddish-colored stools can occur with iron and are a harmless effect, not a bleeding sign. (1)
What should I do if I get diarrhea while taking cefdinir, or after finishing it?
Contact your prescriber promptly, even if the diarrhea starts weeks after you finish the course. This can be a sign of Clostridioides difficile-associated diarrhea (CDAD), which has been reported to occur more than two months after antibacterial treatment, and should not be self-treated with anti-diarrheal medicine before checking with your prescriber. (1)
Is cefdinir safe if I'm allergic to penicillin?
Tell your prescriber about any penicillin allergy before starting cefdinir. Cross-reactivity between penicillins and cephalosporins like cefdinir has been clearly documented and may occur in up to 10% of patients with a penicillin-allergy history. Your prescriber will weigh this risk before prescribing. (1)
What is the mechanism of action of cefdinir?
Cefdinir is a third-generation cephalosporin that inhibits bacterial cell-wall synthesis by binding penicillin-binding proteins, leading to cell lysis and death in susceptible Gram-positive and Gram-negative organisms. It is stable to a number of beta-lactamase enzymes that inactivate other beta-lactam antibiotics. (1)
What is the generic name of Cefdinir?
The generic name is cefdinir. (1)
What class of drug is cefdinir?
Cefdinir is classed as: Third-generation cephalosporin antibiotic. (1)
References
- CEFDINIR capsule -- full prescribing informationU.S. Food and Drug Administration / DailyMed (NIH), full prescribing information · United States · dated 2026-01-01 · accessed 2026-07-30 · source 1
- CEFDINIR CAPSULE [NORTHWIND HEALTH COMPANY, LLC] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 2
- Cefdinir — FDA approval record (Drugs@FDA ANDA065473)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 3
- cefdinir — RxNorm normalized drug concept (RXCUI 1306064)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 4
Brand names by country
Single-ingredient cefdinir names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
United States
- Cefdinir (generic; Omnicef brand discontinued) (1)FDA approved currently labeled generic only · 300 mg capsule, 125 mg/5 mL oral suspension, 250 mg/5 mL oral suspension · Multiple generic manufacturers (original Omnicef brand, Abbott/originally Fujisawa-derived, discontinued)