Cefixime
An oral third-generation cephalosporin for urinary and throat infections, and a single-dose alternative for gonorrhea when ceftriaxone cannot be used.
Drug card
- Class
- Cephalosporin
- How it works
- Binding penicillin-binding proteins so the bacterial wall is never cross-linked
- Used for
- Uncomplicated urinary tract infections
- Gonorrhea, when ceftriaxone is not available
- Throat and tonsil infections
- Bacterial dysentery
- Known for
- Diarrhea and loose stools (common)
- Its name
- cef- means a cephalosporin
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does cefixime work?
Cefixime is an oral third-generation cephalosporin. It is stable to many beta-lactamases and acts mainly on Gram-negative bacteria such as E. coli, Proteus mirabilis, H. influenzae and N. gonorrhoeae, plus streptococci. Most staphylococci, enterococci, Listeria and Pseudomonas resist it, and it does little against ESBL producers.
Like other cephalosporins: Cephalosporins are beta-lactams first derived from Acremonium (Cephalosporium) fungi. Like penicillins, they bind and inactivate penicillin-binding proteins, so peptidoglycan is not cross-linked and the bacterial cell wall weakens and lyses. They withstand many beta-lactamases; from first to third generation, Gram-negative activity rises and Gram-positive activity falls.
Uses
What is cefixime used for?
- Uncomplicated urinary tract infections
- Gonorrhea, when ceftriaxone is not available
- Throat and tonsil infections
- Bacterial dysentery
Side effects
Side effects of cefixime
- Diarrhea and loose stools (common)Known for
- Nausea
- Stomach pain
- Indigestion and wind
- Allergic reactions, including anaphylaxisSerious
- C. difficile colitisSerious
- Severe skin reactions (SJS, TEN)Serious
- Hepatitis and jaundiceSerious
- Acute kidney failureSerious
- SeizuresSerious
- Prolonged prothrombin time and bleedingSerious
- Vaginitis and genital itching
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Penicillin allergy: up to 1 in 10 may cross-react, so it is used with caution.
- Warfarin: prothrombin time can rise, with or without bleeding, so clotting is checked.
- Carbamazepine levels can rise when the two are taken together.
- Kidney impairment and dialysis: the dose is adjusted.
Good to know: WHO classes it as a Watch antibiotic and lists it as a second choice for gonorrhea and acute bacterial dysentery.
Remember it
A way to remember it
Climb the generations, gain the Gram-negatives: from first to third generation, Gram-negative reach grows while Gram-positive reach shrinks.
First-generation cefalexin suits streptococcal and staphylococcal skin infections. Second-generation cefuroxime adds beta-lactamase-producing H. influenzae. Third-generation ceftriaxone and cefixime reach gonococci, E. coli and Klebsiella, and cefixime misses most staphylococci.
Written for biofideX
Its name
cef- means cephalosporin
Cefalexin, cefuroxime, ceftriaxone and cefixime share it. Older US names keep the spelling ceph- (cephalexin).
- Every drug name stem
Its class
Cephalosporins
Other cephalosporins with a card:
Easily mixed up with penicillins and carbapenems.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Cefixime capsules: label (DailyMed)
- Cefixime (NCI Thesaurus)
- Gonococcal Infections Among Adolescents and Adults: STI Treatment Guidelines (CDC)
- WHO Model List of Essential Medicines, 24th list (2025) (WHO)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Antibiotics: the cell wall
Cefixime is one of 12 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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