Is oral Ceftazidime (Ceftazidime) effective for treating infections?

Oral Ceftazidime Is Not Effective for Treating Infections

Oral ceftazidime is not available as a formulation and cannot be used to treat infections by the oral route. 1 Ceftazidime is only available as an intravenous (IV) or intramuscular (IM) formulation, as it would not achieve adequate bioavailability if administered orally.

Ceftazidime Administration Routes and Pharmacokinetics

• Ceftazidime is a third-generation cephalosporin that must be administered parenterally (IV or IM) to achieve therapeutic concentrations 1, 2
• After IV administration, ceftazidime is primarily eliminated unchanged by the kidneys (80-90% over 24 hours) 1
• The half-life of ceftazidime is approximately 2 hours in patients with normal renal function 1
• Dosage adjustment is required for patients with impaired renal function, as the drug is eliminated almost exclusively by the kidneys 1

Clinical Applications of Ceftazidime

Ceftazidime is indicated for various infections when administered parenterally:

• Gram-negative infections, particularly those caused by Pseudomonas aeruginosa 1, 2
• Infections caused by Enterobacteriaceae, including beta-lactamase-producing strains 1
• Lower respiratory tract infections 3, 2
• Urinary tract infections 3, 2
• Skin and soft tissue infections 3, 2
• Febrile neutropenia, often in combination with other agents 4

Ceftazidime in Febrile Neutropenia

For febrile neutropenia, ceftazidime is often used as part of combination therapy:

• The WHO recommends piperacillin-tazobactam as first choice for non-ambulatory patients with febrile neutropenia, with ceftazidime considered redundant due to the inclusion of piperacillin-tazobactam 4
• Ceftazidime can be combined with an aminoglycoside as a two-drug regimen for febrile neutropenia 4
• Some studies have shown concerns about higher mortality with cefepime compared to other beta-lactams like ceftazidime 4

Novel Formulation: Ceftazidime-Avibactam

A newer formulation combining ceftazidime with avibactam has expanded the spectrum of activity:

• Ceftazidime-avibactam is effective against carbapenem-resistant Gram-negative bacteria that produce serine carbapenemases 4, 5
• It shows significant reduction in mortality (RR 0.55,95% CI 0.42-0.72) and treatment failure (RR 0.49,95% CI 0.34-0.70) compared to other antimicrobial options 4, 5
• For metallo-β-lactamase-producing infections, ceftazidime-avibactam combined with aztreonam is recommended, showing lower 30-day mortality (19.2% vs 44%) 4, 5

Limitations and Considerations

• Intermittent bolus dosing of ceftazidime in critically ill patients may result in variable plasma concentrations, potentially leading to inadequate drug levels 6
• Continuous infusion may be more appropriate in critical infections to maintain adequate plasma concentrations 6
• Resistance to ceftazidime can develop through hydrolysis by beta-lactamases, alteration of penicillin-binding proteins, and decreased permeability 1

Alternative Oral Options

Since oral ceftazidime is not available, alternative oral options for treating infections include:

• Fluoroquinolones (e.g., ciprofloxacin, ofloxacin) for certain gram-negative infections 3
• Amoxicillin-clavulanate for broader coverage including some gram-positive organisms 4
• Oral third-generation cephalosporins (e.g., cefixime, cefpodoxime) for certain susceptible infections

Conclusion

For infections requiring ceftazidime, parenteral administration is necessary. When oral therapy is preferred, clinicians must select an appropriate alternative oral antibiotic based on the pathogen's susceptibility and the infection site.