Ceftazidime Dosing for Pseudomonas UTI in Elderly Patient with Cipro Allergy
For an 87-year-old male with recurrent UTI caused by Pseudomonas aeruginosa who is susceptible to ceftazidime and has a ciprofloxacin allergy, the recommended dose is 2 grams IV every 8 hours for 10-14 days.
Dosing Considerations
- The FDA-approved dosing for ceftazidime for complicated urinary tract infections is 500 mg IV every 8-12 hours 1
- However, for Pseudomonas infections specifically, higher doses are recommended: 2 grams IV every 8 hours 2, 1
- For elderly patients, renal function assessment is crucial as ceftazidime is primarily excreted by glomerular filtration 1
- If creatinine clearance is reduced, dose adjustment is necessary according to the following schedule 1:
- CrCl 50-31 mL/min: 1 gram every 12 hours
- CrCl 30-16 mL/min: 1 gram every 24 hours
- CrCl 15-6 mL/min: 500 mg every 24 hours
- CrCl <5 mL/min: 500 mg every 48 hours
Duration of Therapy
- For complicated UTIs caused by Pseudomonas aeruginosa, a treatment course of 10-14 days is recommended 2
- Treatment should continue for at least 2 days after signs and symptoms of infection have disappeared 1
- In recurrent UTIs, especially in elderly patients, the full 14-day course is often preferred to ensure complete eradication 2
Administration Considerations
- Ceftazidime should be administered intravenously for systemic Pseudomonas infections 1
- Intermittent bolus dosing may result in variable plasma concentrations, particularly in critically ill patients 3
- Consider a loading dose of 2 grams followed by maintenance dosing based on renal function 1
- Continuous infusion may be an alternative in some cases (100-150 mg/kg/day) but is generally reserved for specific situations 2
Monitoring Recommendations
- Monitor renal function regularly during treatment, especially in elderly patients 1
- Assess clinical response within 72 hours of initiating therapy 2
- Consider follow-up urine cultures after completion of therapy to confirm eradication 2
- Watch for potential adverse effects including hypersensitivity reactions, Clostridium difficile-associated diarrhea, and superinfections 4
Important Clinical Considerations
- Ceftazidime has excellent activity against Pseudomonas aeruginosa and is an appropriate choice when ciprofloxacin cannot be used due to allergy 2, 1
- In elderly patients, the risk of adverse effects may be higher due to decreased renal function and potential drug interactions 1
- Ensure adequate hydration during treatment to maintain renal function and help flush the urinary tract 2
- For patients with recurrent UTIs, consider urological evaluation to identify any underlying structural abnormalities once the acute infection resolves 5
Common Pitfalls to Avoid
- Underdosing ceftazidime for Pseudomonas infections can lead to treatment failure and development of resistance 3
- Failing to adjust dosage based on renal function can lead to toxicity in elderly patients 1
- Not completing the full course of antibiotics may result in recurrence of infection 2
- Inadequate monitoring of clinical response and potential adverse effects 4