[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Beta-lactams](https://durgical.com/en/pharmacology/classes/beta-lactams/) › Cefdinir

# Cefdinir

## Beta-lactams?

Beta-lactams

Oral third-generation cephalosporin for otitis, pharyngitis, sinusitis and mild pneumonia; with iron it can turn the stools red.

Updated Nov 1, 2026

## Quick facts

**Group**
[Beta-lactams](https://durgical.com/en/pharmacology/classes/beta-lactams/)

**Target**
Penicillin-binding proteins (bacterial transpeptidases)

**Used for**
Acute otitis media in children

**Key effects**
Diarrhoea · Vaginal candidiasis and vaginitis · Nausea

**Monitor**
Diarrhoea during and after treatment · Stool colour

**ATC**
J01DD15

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

✂**Penicillin-binding proteins (bacterial transpeptidases)**Cefdinir

ⓘ No structure of cefdinir bound to a PBP is published; the figure shows cefixime, another oral third-generation cephalosporin with a vinyl group in the same position, acylating Neisseria gonorrhoeae PBP2.

**Target in 3D:** Penicillin-binding proteins (bacterial transpeptidases). PDB structure 6P55 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/6P55) · Drag to rotate · pinch to zoom

Cefdinir acylates the penicillin-binding proteins and blocks peptidoglycan cross-linking, so it is bactericidal. It is stable against some, but not all, beta-lactamases and is used mainly against pneumococci, S. pyogenes, H. influenzae and Moraxella in outpatient respiratory infections.

- Absorbed by mouth (low bioavailability)
- Acylates the PBPs of the bacterial wall
- Peptidoglycan cross-linking stops
- The bacterium lyses (bactericidal)

## Indications

- Acute otitis media in children [Acute otitis media →](https://durgical.com/en/conditions/acute-otitis-media/)
- Pharyngitis and tonsillitis [Streptococcal pharyngitis →](https://durgical.com/en/conditions/streptococcal-pharyngitis/)
- Mild community-acquired pneumonia and flares of chronic bronchitis [Community-acquired pneumonia →](https://durgical.com/en/conditions/community-acquired-pneumonia/)
- Acute maxillary sinusitis [Acute rhinosinusitis →](https://durgical.com/en/conditions/acute-rhinosinusitis/)
- Uncomplicated skin infections

## Adverse effects

### Common

- Diarrhoea (the most common)
- Vaginal candidiasis and vaginitis
- Nausea, abdominal pain and headache
- Reddish stools when combined with iron

### Serious (rare, important)

- Severe allergic reactions
- Clostridioides difficile diarrhoea, from mild to fatal colitis

## Contraindications

- Allergy to cephalosporins

## Key interactions

**Aluminium or magnesium antacids**
Reduce absorption; doses are separated by at least 2 hours.

**Iron supplements and multivitamins with iron**
Reduce absorption (separated by at least 2 hours) and form a complex that turns stools red.

**Probenecid**
Reduces renal excretion and raises cefdinir levels.

## What is monitored

- Diarrhoea during and after treatment
- Stool colour: reddish from iron is harmless; blood or black stools are not

## Administration and safety

- Oral, as capsules or suspension
- Separate from antacids and iron supplements
- The suspension contains sucrose, worth knowing in people with diabetes

## Pregnancy and breastfeeding

Animal studies showed no harm and there are no adequate studies in pregnant women; it is used only when clearly needed.

## Nursing care

- Ask about penicillin and cephalosporin allergy
- Explain to carers that reddish stools from iron are not blood, and when to seek care
- Review the iron supplements and antacids the person uses
- Teach to finish the course

## Pharmacokinetics

**Absorption**
Oral, with low bioavailability (around 25% for the suspension); aluminium or magnesium antacids and iron reduce it.

**Metabolism**
Hardly metabolised.

**Elimination**
Mainly renal.

**Half-life**
Short, about 1.7 hours.

## Memory aid

«Cef-DINIR, RUBY stools»: with iron, cefdinir forms a red complex in the gut that looks alarming but is not blood.

## Test yourself

Think of the answer, then tap the question to see it.

## A child on cefdinir and an iron supplement has reddish stools. What is the most likely cause?

A non-absorbable complex of cefdinir and iron in the gut; it is harmless, though bleeding is ruled out if there are other signs.

## Which over-the-counter products reduce cefdinir absorption?

Aluminium or magnesium antacids and iron supplements or multivitamins; they are separated by at least 2 hours.

## Which generation does cefdinir belong to?

The third generation of oral cephalosporins.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/cefdinir/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 3

- [Cefpodoxime](https://durgical.com/en/pharmacology/cefpodoxime/)
- [Cefixime](https://durgical.com/en/pharmacology/cefixime/)
- [Cefuroxime](https://durgical.com/en/pharmacology/cefuroxime/)

## Related conditions 4

- [Acute otitis media](https://durgical.com/en/conditions/acute-otitis-media/)
- [Streptococcal pharyngitis](https://durgical.com/en/conditions/streptococcal-pharyngitis/)
- [Community-acquired pneumonia](https://durgical.com/en/conditions/community-acquired-pneumonia/)
- [Acute rhinosinusitis](https://durgical.com/en/conditions/acute-rhinosinusitis/)

[← Back to the class: Beta-lactams](https://durgical.com/en/pharmacology/classes/beta-lactams/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - CEFDINIR capsule](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c493e78b-afa3-4f74-8305-75e5f3817df0) (DailyMed (U.S. National Library of Medicine), 2026); [Cefdinir: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a698001.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [Crystal structure of transpeptidase domain of PBP2 from Neisseria gonorrhoeae acylated by cefixime](https://www.rcsb.org/structure/6P55) (RCSB Protein Data Bank, 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/pharmacology/cefdinir/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/cefdinir/