Cefdinir

1 medicine

Cefdinir is a third-generation cephalosporin antibiotic used for ear, sinus, throat, and skin infections. It must not be used by anyone with a history of severe allergic reaction to penicillins or cephalosporins.

Omnicef

Cefdinir

300mg

Omnicef is a antibiotics medication containing Cefdinir, available as 300mg tablets.

from $3.35 / tablet View

Key facts

  • Cefdinir (sold as Cefdinir and under various brand names) is a third-generation cephalosporin antibiotic that treats a broad range of bacterial infections.
  • It is usually taken once or twice a day for 5 to 10 days, and can be taken with or without food.
  • Do not take cefdinir if you have had a severe allergic reaction, such as anaphylaxis or hives, to a penicillin or cephalosporin antibiotic.
  • Seek urgent care for facial or throat swelling, severe watery or bloody diarrhea, or a widespread rash.

What cefdinir treats

Cefdinir treats bacterial ear infections (otitis media), sinusitis, throat infections, community-acquired pneumonia, and uncomplicated skin infections caused by susceptible bacteria. It is not effective against colds, flu, or other viral illnesses, and should not be used for them.

How cefdinir works

Cefdinir stops susceptible bacteria from correctly assembling their outer cell wall. Without an intact wall the bacteria cannot withstand internal pressure, so they break apart and die, letting your immune system finish clearing the infection.

Before you take it

  • Avoid cefdinir if you have a history of severe penicillin or cephalosporin allergy.
  • Tell your prescriber about kidney disease, since the dose may need adjusting.
  • Iron supplements and antacids containing aluminium or magnesium reduce cefdinir absorption; space them at least two hours apart from your dose.
  • If you or your child takes cefdinir alongside iron drops or iron-fortified formula, stools may turn reddish; this is a harmless colour change, not blood, but mention it to your pharmacist if you are unsure.

Side effects

Common effects include diarrhea, nausea, headache, and mild rash.

Stop and seek urgent medical care for any of these:

  • Swelling of the face, lips, tongue, or throat, or hives with difficulty breathing.
  • Severe or bloody diarrhea, which can signal a serious gut infection (C. difficile colitis).
  • A widespread blistering rash, or fever with a spreading rash.

Safety essentials

  • Never take cefdinir if you have had a severe reaction to any penicillin or cephalosporin; this cross-reaction risk is an absolute contraindication.
  • Watery or bloody diarrhea can develop during treatment or for weeks after it ends, and needs prompt medical review rather than an over-the-counter remedy.
  • Finish the full course even if you feel better early, and keep iron or antacid doses well separated from cefdinir so they don't blunt its effect.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.