A standard course of cefixime for a urinary tract infection is 7 days, though your prescriber may extend it to 14 days depending on the type and severity of infection. The usual dose is 400 mg taken once daily, or split into two 200 mg doses twelve hours apart.
Standard Duration for Uncomplicated UTIs
For a straightforward bladder infection (uncomplicated cystitis), cefixime is typically prescribed for 7 days at 400 mg once a day. This is the most common course length you’ll see on a prescription. Some clinicians extend the course to 10 or even 14 days if the infection involves the kidneys, if you have complicating factors like diabetes or an abnormal urinary tract, or if symptoms haven’t fully cleared by the end of the first week.
Cefixime isn’t usually a first-choice antibiotic for simple bladder infections. Shorter-course options like nitrofurantoin (5 days) or a single dose of fosfomycin are preferred in most guidelines because they work well against common UTI bacteria while preserving broader antibiotics for tougher infections. Cefixime tends to be prescribed when those first-line options can’t be used, whether due to allergies, resistance patterns, or other medical considerations.
Why Your Prescriber Chose Cefixime
Cefixime is a third-generation cephalosporin, meaning it belongs to a class of antibiotics that can handle a wider range of bacteria than older options. Clinical guidelines from the Infectious Diseases Society of America list third-generation cephalosporins as a recommended choice for complicated UTIs, both with and without signs of a body-wide infection. So if your doctor prescribed cefixime rather than a more common UTI antibiotic, it may be because your infection is more complex or because the bacteria involved are resistant to simpler treatments.
That said, resistance to cefixime itself is a growing concern. A 2024 study of E. coli isolates from UTI patients in Lebanon found that roughly 56% to 70% of samples were resistant to cefixime, depending on the patient’s age group. Among bacteria that produced certain protective enzymes (called ESBL producers), resistance to cefixime reached 100%. This is why urine cultures matter. If your doctor ordered one, the results will confirm whether cefixime is the right fit for your specific infection.
How to Take It
You can take cefixime with or without food. If you’re prescribed the once-daily 400 mg dose, pick a consistent time each day and stick with it. If your prescription splits the dose into 200 mg twice a day, space the doses about 12 hours apart.
Finish the entire course, even if your symptoms disappear after two or three days. Stopping early increases the chance that surviving bacteria will bounce back, potentially in a form that’s harder to treat. If you miss a dose, take it as soon as you remember, but skip it if your next dose is almost due. Don’t double up.
What to Expect While Taking It
The most common side effects are digestive: diarrhea, stomach pain, gas, nausea, and heartburn. These are usually mild and settle down once you finish the course. Eating a small meal or snack alongside your dose can help if nausea is an issue.
Some side effects need immediate attention. Watery or bloody stools with stomach cramps or fever, whether during treatment or even weeks after finishing, can signal a serious intestinal infection caused by an overgrowth of harmful bacteria. An allergic reaction (rash, hives, swelling of the face or throat, difficulty breathing) also requires urgent care. These reactions are uncommon but worth knowing about so you can act quickly.
Most people notice their UTI symptoms, particularly the burning and urgency, improving within 48 to 72 hours of starting cefixime. If you don’t see any improvement by day three, contact your prescriber. The bacteria may be resistant to cefixime, and a switch to a different antibiotic could be necessary.
Dosing for Children
Children six months and older are dosed by weight: 8 mg per kilogram of body weight per day, given either as a single daily dose or split into two doses twelve hours apart. A child weighing about 20 kg (44 pounds), for example, would take around 150 mg per day. Children over 12 years old or weighing more than 45 kg follow the standard adult dose of 400 mg daily. The FDA prescribing information for cefixime does not specify a fixed treatment duration for pediatric UTIs, so the length of the course is determined by the prescribing clinician based on the child’s situation.
Cefixime During Pregnancy
Cefixime carries an FDA pregnancy category B rating, meaning animal studies have not shown harm to a developing fetus, though controlled studies in pregnant women are lacking. It is generally considered an option when the benefit clearly outweighs any theoretical risk. UTIs during pregnancy do need prompt treatment because untreated infections can progress to kidney infections and increase the risk of preterm delivery. Your prescriber will weigh the antibiotic choice and duration based on your trimester and the severity of infection.