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Omnicef

Generic name: cefdinir (SEF dih neer)
Brand name: Omnicef, Omnicef Omni-Pac
Drug class: Third generation cephalosporins

Medically reviewed by Philip Thornton, DipPharm. Last updated on Feb 12, 2021.

What is Omnicef?

Omnicef (cefdinir) belongs to a group of drugs called cephalosporin (SEF a low spor in) antibiotics. Cefdinir works by fighting bacteria in your body.

Omnicef is an antibiotic that is used to treat many different types of infections caused by bacteria.

Warnings

Do not take Omnicef if you are allergic to cefdinir, or to similar antibiotics, such as Ceftin, Cefzil, Keflex, and others.

Before taking Omnicef, tell your doctor if you are allergic to any drugs (especially penicillin). Also tell your doctor if you have kidney disease or a history of intestinal problems.

Take Omnicef for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Cefdinir will not treat a viral infection such as the common cold or flu.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, stop taking this medicine and call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

Before taking this medicine

To make sure Omnicef is safe for you, tell your doctor if you have ever had:

  • kidney disease (or if you are on dialysis);

  • intestinal problems, such as colitis; or

  • an allergy to any drugs (especially penicillins).

Omnicef liquid contains sucrose. Talk to your doctor before using this form of cefdinir if you have diabetes.

Tell your doctor if you are pregnant or breastfeeding.

How should I take Omnicef?

Take Omnicef exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medicine guides or instruction sheets.

Shake the oral suspension (liquid) before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

You may take this medicine with or without food.

Use this medicine for the full prescribed length of time, even if your symptoms quickly improve. Skipping doses can increase your risk of infection that is resistant to medication. Cefdinir will not treat a viral infection such as the flu or a common cold.

Cefdinir can affect the results of certain medical tests. Tell any doctor who treats you that you are using cefdinir.

Store at room temperature away from moisture and heat. Throw away any unused liquid medicine that is older than 10 days.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include nausea, vomiting, stomach pain, diarrhea, or a seizure.

What to avoid

Avoid using antacids or mineral supplements that contain aluminum, magnesium, or iron within 2 hours before or after taking a dose of this medicine. Antacids or iron can make it harder for your body to absorb cefdinir. This does not include baby formula fortified with iron.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, call your doctor before using anti-diarrhea medicine.

Omnicef side effects

Get emergency medical help if you have signs of an allergic reaction to Omnicef (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Call your doctor at once if you have:

  • severe stomach pain, diarrhea that is watery or bloody (even if it occurs months after your last dose);

  • fever, chills, body aches, flu symptoms;

  • pale skin, easy bruising, unusual bleeding;

  • seizure (convulsions);

  • fever, weakness, confusion;

  • dark colored urine, jaundice (yellowing of the skin or eyes); or

  • kidney problems - little or no urination, swelling in your feet or ankles, feeling tired or short of breath.

Common Omnicef side effects may include:

  • nausea, vomiting, stomach pain, diarrhea;

  • vaginal itching or discharge;

  • headache; or

  • rash (including diaper rash in an infant taking liquid cefdinir).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Omnicef?

Tell your doctor about all your other medicines, especially:

  • probenecid; or

  • vitamin or mineral supplements that contain iron.

This list is not complete. Other drugs may interact with cefdinir, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Frequently asked questions

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Omnicef only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.