Health information to help you understand symptoms. It isn't a diagnosis.
Check symptoms

Cefdinir

Brand names: Omnicef (brand discontinued)

Cefdinir is a cephalosporin antibiotic often used for ear, sinus, throat, and skin infections, especially in children.

Brand namesOmnicef (brand discontinued)
Type of medicineCephalosporin antibiotic
Prescription?Prescription
ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.

Overview

It kills bacteria. It doesn't work on viruses.

What it's used for

  • Ear infections
  • Sinus infections
  • Strep throat
  • Some pneumonias
  • Skin infections

How to take it

  • Take it with or without food.
  • Take iron and antacids at least 2 hours apart from it.
  • Finish the full course.

Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.

Side effects

Common side effects

  • Diarrhea
  • Nausea
  • Red or reddish stools (harmless, mostly with iron formula or iron supplements)
Call 911Swelling of the face, lips, or throat, hives, or trouble breathing
Call 911A blistering, peeling, or widespread red rash, especially with fever
Call your provider todaySevere watery or bloody diarrhea, even weeks after finishing (possible C. diff infection)

Warnings

  • Tell your provider about any penicillin or cephalosporin allergy.

Other medicines, foods, and alcohol

  • Iron and antacids with aluminum or magnesium lower absorption.

Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.

Pregnancy and breastfeeding

Talk with your provider; cephalosporins are commonly used in pregnancy.

Missed doses, overdose, and storage

If you miss a dose

Take it as soon as you remember. If it's almost time for the next dose, skip the missed one. Don't double up, and still finish the full course.

If someone takes too much

Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.

Storing it

Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.

Conditions it's used for

Sources

Last updated 2026-11-13.