Cefdinir safety — what to know before you take it

Cefdinir is a common oral antibiotic used for ear infections, sinusitis, bronchitis and some skin infections. It works well for many patients, but a few safety points are worth knowing so you get better without surprises.

Common side effects and what to expect

Most people tolerate cefdinir fine. The usual side effects are mild: diarrhea, nausea, stomach pain, headache, and a skin rash. If you get loose stools that are severe or watery, tell your doctor right away — antibiotics can sometimes trigger C. difficile infection, which needs prompt treatment.

A weird but important effect: if your child is taking iron (or drinking iron-fortified formula) while on cefdinir, stool can turn reddish or rust-colored. It looks alarming but it’s usually harmless. Still, call your pediatrician if you notice this.

Watch for signs of an allergic reaction: hives, swelling of the face or throat, trouble breathing, or a severe rash. If any of those happen, seek emergency care.

Key precautions, interactions and dosing tips

Take cefdinir exactly as prescribed. Common adult dosing is 300 mg every 12 hours or 600 mg once daily. For children, a typical plan is about 7 mg/kg every 12 hours (or 14 mg/kg once daily) — but your clinician will give the exact dose and length based on the infection and the child’s weight.

If you have kidney problems your doctor may lower the dose or lengthen the time between doses. Don’t try to adjust it yourself — talk to your prescriber or pharmacist.

Drug interactions to remember: antacids or supplements with aluminum or magnesium can reduce cefdinir absorption. More importantly, iron supplements or iron-fortified formula can cause that reddish stool and also can lower how much antibiotic your body absorbs. Try to separate doses by a couple of hours when possible, or follow specific instructions from your provider.

Probenecid can increase cefdinir levels, so your doctor will check for any interacting drugs. If you’re taking other medications, list them when you get your prescription.

Avoid unnecessary use. Using antibiotics when they’re not needed can cause resistance and more side effects. If your symptoms are mild and viral (common cold), antibiotics won’t help.

Storage and missed doses: store cefdinir at room temperature away from moisture. If you miss a dose, take it as soon as you remember unless it’s almost time for the next one — don’t double up.

Final note: if you get new or worsening symptoms, severe diarrhea, high fever, jaundice (yellow skin/eyes), or signs of allergy, contact your doctor immediately. For most people, cefdinir is effective and safe when used properly.