Ceftazidime !

A third-generation intravenous cephalosporin with activity against Pseudomonas aeruginosa, for serious hospital infections.

Updated 2026-11-01

Class: Beta-lactams
Enzyme: Penicillin-binding proteins, mainly PBP3
ATC code: J01DD02
WHO Model List of Essential Medicines

Penicillin-binding proteins, mainly PBP3Ceftazidime

The figure shows PBP3 from Pseudomonas aeruginosa acylated by ceftazidime, bonded to the active-site serine.

Target in 3D: Penicillin-binding proteins, mainly PBP3. PDB structure 3PBO (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Ceftazidime acylates the PBPs, mainly PBP3 of gram-negative rods. Its side chain makes it stable to many β-lactamases and lets it cross the outer membrane of Pseudomonas aeruginosa: it is the third-generation cephalosporin with useful activity against this organism. In exchange, it is weak against gram-positives such as staphylococci. ESBLs and AmpC β-lactamases hydrolyse it.

Crosses the Pseudomonas outer membrane
Acylates PBP3, which builds the division septum
The bacterium grows into filaments without dividing
The wall fails and the bacterium lyses

Pharmacokinetics

Absorption: Intravenous or intramuscular.
Distribution: Low protein binding; reaches the cerebrospinal fluid when the meninges are inflamed.
Elimination: Almost only by the kidney, unchanged; adjusted in kidney failure.
Half-life: About 2 hours; much longer when kidney function is reduced.

Indications

Hospital-acquired pneumonia and other lower respiratory infections due to Pseudomonas and other gram-negatives.
Complicated urinary tract infections. Urinary tract infection (acute cystitis) →
Sepsis due to susceptible gram-negatives. Sepsis and septic shock →
Meningitis due to Pseudomonas or other susceptible gram-negatives. Bacterial meningitis →
Bone and joint infections due to gram-negatives. Osteomyelitis →

Adverse effects

Common

Phlebitis or injection-site pain
Diarrhoea, nausea
Rash, eosinophilia, positive Coombs test

Contraindications

Hypersensitivity to ceftazidime or other cephalosporins

Key interactions

Aminoglycosides and potent diuretics such as furosemide: Higher risk of kidney toxicity; kidney function is monitored.
Chloramphenicol: Antagonism in vitro; the combination is avoided.
Oral anticoagulants (warfarin): Cephalosporins can lower prothrombin activity; the INR is monitored.

What is monitored

Creatinine and urine output
Neurological status in kidney failure
Cultures and susceptibility tests

Administration and safety

Intravenous or deep intramuscular.
Do not confuse ceftazidime with ceftriaxone or with ceftazidime + avibactam.

Nursing care

Before the first dose: ask about allergy to penicillins, cephalosporins and other β-lactams, and what the reaction was.
In kidney failure, watch for confusion, myoclonus or seizures (drug accumulation).
Monitor urine output and creatinine, more so with aminoglycosides.
Teach the patient to report watery or bloody diarrhoea, even weeks after the course ends.

Pregnancy and breastfeeding

Animal studies showed no fetal harm and there are no controlled studies in pregnant women; used if clearly needed.

Test yourself

Think of the answer, then tap the question to see it.

How does ceftazidime's spectrum differ from ceftriaxone's?

Ceftazidime is active against Pseudomonas aeruginosa but weak against gram-positives; ceftriaxone covers pneumococci and streptococci well but not Pseudomonas.

A patient with kidney failure on ceftazidime develops confusion and myoclonus. What is suspected?

Neurotoxicity from drug accumulation (encephalopathy, myoclonus, even non-convulsive status epilepticus); the dose is reviewed against kidney function.

Which bacterial enzymes inactivate ceftazidime?

Extended-spectrum β-lactamases (ESBLs), AmpC enzymes and carbapenemases; that is why it was combined with avibactam.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: Ceftazidime Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); DailyMed - CEFTAZIDIME injection, powder, for solution (DailyMed (U.S. National Library of Medicine), 2026); RCSB PDB - 3PBO: Crystal structure of PBP3 complexed with ceftazidime (RCSB Protein Data Bank, 2026); Farmacología básica y clínica (Katzung), cap. 43 (McGraw Hill, 2025).

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Representative model, for educational purposes only.