Cefixime Side Effects: What to Expect and When to Call Your Doctor

Cefixime Side Effects: What's Normal and What's Not

Cefixime (brand name Suprax) is a widely used third-generation cephalosporin antibiotic prescribed for urinary tract infections, ear infections, strep throat, bronchitis, and gonorrhea. Like any antibiotic, it comes with potential side effects—most of them mild and manageable, but some that require immediate medical attention.

This guide breaks down exactly what to expect when taking Cefixime, which side effects are common versus serious, and when you should call your doctor.

What Is Cefixime? (Quick Overview)

Cefixime is an oral antibiotic that kills bacteria by disrupting their cell wall synthesis. It's available as 400 mg capsules, chewable tablets (100 mg, 150 mg, 200 mg), and oral suspension for children. A typical adult dose is 400 mg once daily, and treatment usually lasts 5–14 days depending on the infection.

For a more detailed overview, see our full guide: What Is Cefixime? Uses, Dosage, and What You Need to Know.

Common Side Effects of Cefixime

These side effects are relatively frequent and usually don't require medical intervention unless they become severe or persistent:

• Diarrhea or loose stools — The most common side effect, affecting up to 16% of patients. Cefixime disrupts normal gut bacteria, which can lead to watery or loose bowel movements.
• Abdominal pain or stomach discomfort — Cramping or general stomach upset during treatment.
• Nausea — Feeling queasy, especially when taken on an empty stomach.
• Indigestion (dyspepsia) — Bloating, heartburn, or an uncomfortable feeling after eating.
• Flatulence (gas) — Another GI side effect related to changes in gut flora.
• Headache — Mild to moderate headaches that typically resolve on their own.
• Vomiting — Less common than nausea but can occur, especially in children.
• Vaginal itching or discharge — Cefixime can disrupt vaginal flora and lead to yeast infections.

Most of these side effects improve as your body adjusts to the medication and resolve completely once you finish your course.

Serious Side Effects: When to Call Your Doctor

These side effects are rare but can be dangerous. Contact your doctor or seek emergency care immediately if you experience any of the following:

• Severe allergic reaction (anaphylaxis) — Hives, swelling of your face, lips, tongue, or throat, difficulty breathing, rapid heartbeat, dizziness. Call 911 immediately.
• Clostridioides difficile-associated diarrhea (C. diff) — Severe, watery diarrhea that won't stop, bloody stools, abdominal cramping, and fever. This can occur during treatment or even weeks after finishing Cefixime. C. diff is a serious infection that requires its own treatment.
• Severe skin reactions — Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN): widespread rash, blistering, peeling skin, sores in mouth/eyes. These are medical emergencies.
• Seizures — Especially in patients with renal impairment or those taking high doses.
• Liver problems (hepatic dysfunction) — Yellowing of skin or eyes (jaundice), dark urine, persistent nausea, extreme fatigue, upper-right abdominal pain.
• Hemolytic anemia — Unusual tiredness, pale skin, rapid heartbeat, dark urine, shortness of breath.
• Kidney problems — Decreased urination, swelling in legs or feet, confusion.
• Blood disorders (thrombocytopenia) — Unusual bruising, bleeding that won't stop, tiny red spots on skin (petechiae).
• Superinfection — A new infection caused by resistant bacteria or fungi that develops during antibiotic treatment. Signs include new fever, white patches in mouth, or worsening symptoms.

Side Effects in Specific Populations

Children

Cefixime is approved for children 6 months and older. The most common side effect in kids is diarrhea. The oral suspension and chewable tablets make dosing easier, but note that chewable tablets contain phenylalanine—a concern for children with phenylketonuria (PKU).

Pregnant Women

Cefixime is Pregnancy Category B, meaning animal studies have not shown risk to the fetus. However, human data is limited. Your doctor will weigh the benefits against potential risks.

Breastfeeding

It's unknown whether Cefixime passes into breast milk. Talk to your doctor if you're breastfeeding.

Patients with Kidney Disease

Cefixime is excreted by the kidneys. If your creatinine clearance is 20 mL/min or less, your doctor should reduce the dose. Patients on dialysis need dose adjustments as well.

Patients with Penicillin Allergy

There is a small risk of cross-reactivity between penicillin and cephalosporin antibiotics. If you have a history of severe penicillin allergy (anaphylaxis), Cefixime may not be safe for you. Always tell your doctor about penicillin allergies.

How to Manage Common Side Effects

Here are practical tips to reduce discomfort while taking Cefixime:

• For diarrhea: Stay hydrated. Drink water, clear broths, or electrolyte drinks. Eat bland foods (rice, bananas, toast). Avoid dairy, greasy foods, and caffeine. Probiotics may help restore gut bacteria—ask your doctor before starting them.
• For nausea: Take Cefixime with food. Eat smaller, more frequent meals. Avoid spicy or heavy foods.
• For headache: Over-the-counter acetaminophen (Tylenol) is generally safe to take alongside Cefixime. Stay hydrated.
• For vaginal yeast infection: Over-the-counter antifungal treatments (miconazole, clotrimazole) can help. Let your doctor know if symptoms are severe.
• For gas and bloating: Avoid carbonated beverages and high-fiber foods during treatment. Simethicone (Gas-X) can provide relief.

Important: Do NOT take anti-diarrheal medications like loperamide (Imodium) without asking your doctor first. If your diarrhea is caused by C. diff, anti-diarrheal drugs can make it worse.

Final Thoughts

Most people tolerate Cefixime well. Diarrhea and stomach discomfort are the most common complaints, and they typically resolve once you finish your antibiotic course. Serious side effects are rare but real—know the warning signs so you can act fast if they occur.

If you experience severe diarrhea, an allergic reaction, or any of the serious symptoms listed above, don't wait—contact your doctor or go to the emergency room immediately.

For more about Cefixime—including how it works, what it interacts with, and how to save money on your prescription—explore our other guides:

• What Is Cefixime?
• How Does Cefixime Work?
• Cefixime Drug Interactions
• How to Save Money on Cefixime