How is ceftazidime administered, and what are its dosing guidelines, renal dose adjustments, contraindications, and monitoring recommendations?

Ceftazidime Administration and Dosing

Ceftazidime is administered intravenously or intramuscularly, with standard adult dosing of 1-2 grams every 8 hours, but requires significant dose reduction in renal impairment and higher doses (up to 6 grams/day) for serious Pseudomonas infections. 1

Routes of Administration

Ceftazidime can be given by:

• Intravenous (IV): Bolus over 5 minutes or infusion over 20-30 minutes
• Intramuscular (IM): Deep injection into large muscle mass (upper outer gluteus or lateral thigh)
• Avoid intra-arterial administration 1

Standard Adult Dosing

By Infection Type 1

• Uncomplicated UTI: 250 mg IV/IM every 12 hours
• Complicated UTI: 500 mg IV/IM every 8-12 hours
• Uncomplicated pneumonia/mild skin infections: 500 mg-1 gram IV/IM every 8 hours
• Bone and joint infections: 2 grams IV every 12 hours
• Serious gynecologic/intra-abdominal infections: 2 grams IV every 8 hours
• Meningitis: 2 grams IV every 8 hours
• Life-threatening infections in immunocompromised: 2 grams IV every 8 hours
• Pseudomonas lung infections in cystic fibrosis: 30-50 mg/kg IV every 8 hours (maximum 6 grams/day)

Pediatric Dosing

Neonates and Infants 2, 3, 4

For neonates <32 weeks gestational age 3:

• Postnatal age <14 days: 50 mg/kg/dose IV every 12 hours
• Postnatal age ≥14 days: 50 mg/kg/dose IV every 8 hours

For neonates ≥32 weeks gestational age 3:

• Postnatal age ≤7 days: 50 mg/kg/dose IV every 12 hours
• Postnatal age >7 days: 50 mg/kg/dose IV every 8 hours

For febrile infants 8-21 days old 4:

• 150 mg/kg/day IV divided every 8 hours (combined with ampicillin for UTI or no focus identified)
• For meningitis: 150 mg/kg/day IV divided every 8 hours (combined with ampicillin)

Children (1 month-12 years) 2, 3

• Standard dosing: 100-150 mg/kg/day IV divided every 8 hours
• Serious Pseudomonas infections: 200-300 mg/kg/day IV in 3 divided doses
• Maximum daily dose: 12,000 mg/day for serious Pseudomonas infections 3

Renal Dose Adjustments

Ceftazidime is eliminated almost exclusively by glomerular filtration, making dose adjustment critical in renal impairment. 1

Dosing by Creatinine Clearance 1

CrCl (mL/min)	Dose	Frequency
50-31	1 gram	Every 12 hours
30-16	1 gram	Every 24 hours
15-6	500 mg	Every 24 hours
<5	500 mg	Every 48 hours

Important: If the standard dose for the infection is lower than the renal-adjusted dose, use the lower dose 1

Hemodialysis 1

• Loading dose: 1 gram
• Maintenance: 1 gram after each hemodialysis session
• Mean elimination half-life during dialysis: 4.7 hours 5

Peritoneal Dialysis 1

• Loading dose: 1 gram (or 10 mg/kg)
• Maintenance: 500 mg every 24 hours
• Can be incorporated into dialysis fluid at 250 mg per 2L 1, 6

Continuous Renal Replacement Therapy

• Dosing should be individualized based on therapeutic drug monitoring when available
• Higher doses may be needed due to drug removal during continuous therapies

Special Populations

Elderly Patients 7

• Consider twice-daily dosing (every 12 hours) rather than every 8 hours due to age-related decline in GFR
• Serum creatinine is unreliable for estimating renal function in elderly; use Cockcroft-Gault equation 1
• Trough concentrations after 12 hours typically exceed MIC90 for most pathogens by several-fold

Hepatic Impairment 1

• No dose adjustment required - hepatic dysfunction does not affect ceftazidime pharmacokinetics

Obesity

• No specific dose adjustment required based on obesity alone 8
• Consider actual body weight for dosing calculations

Pharmacokinetics 1, 9

• Peak serum concentrations:
  • 500 mg IV: 42-45 mcg/mL
  • 1 gram IV: 60-90 mcg/mL
  • 2 grams IV: 129-170 mcg/mL
• Half-life: 1.5-2 hours in normal renal function 1, 9
• Protein binding: <10% 1
• Renal excretion: 80-90% unchanged in urine within 24 hours 1
• CSF penetration: Achieves therapeutic levels in inflamed meninges (9.4-9.8 mcg/mL with 2 grams every 8 hours) 1

Contraindications

Absolute contraindication: Hypersensitivity to ceftazidime, any cephalosporin, or components of the formulation 1

Relative contraindications/cautions:

• History of severe penicillin allergy (cross-reactivity risk)
• Severe renal impairment without dose adjustment (risk of neurotoxicity)

Monitoring Recommendations

Routine Monitoring

• Renal function: Baseline and periodic monitoring, especially in elderly or those with baseline impairment
• Clinical response: Fever resolution typically occurs within 2-3 days 10
• Duration: Continue for 2 days after signs/symptoms resolve; longer for complicated infections 1

Therapeutic Drug Monitoring (TDM)

Consider TDM in 11:

• Severe renal impairment (CrCl <30 mL/min)
• Critically ill patients
• Patients not responding to therapy
• Suspected neurotoxicity

Target concentrations:

• Trough levels: Should exceed MIC of pathogen by 4-8 times for optimal efficacy 12
• Neurotoxicity threshold: 78 mg/L 11
• Peak levels: 1 hour post-dose typically 45-70 mg/L for standard doses 10

Neurotoxicity Monitoring 11

High-risk patients (especially with renal impairment):

• Monitor for altered mental status, confusion, myoclonic seizures, encephalopathy
• Risk increases dramatically when trough >78 mg/L 11
• Most cases occur with inadequate renal dose adjustment 11
• Symptoms typically improve within days of discontinuation

Resistance Monitoring

• In cystic fibrosis patients, resistance may develop during therapy 9
• Consider repeat cultures if clinical response inadequate
• Current resistance rates: E. coli shows 47.2% resistance in some settings 13

Critical Care Considerations 12

For critically ill patients with augmented renal clearance:

• May require higher doses (up to 6 grams/day) to achieve target concentrations
• Consider extended infusion (3 hours) for serious infections
• TDM strongly recommended to ensure adequate exposure

Combination therapy 3:

• For carbapenem-resistant organisms, ceftazidime-avibactam combinations are preferred
• For MBL-producers, combine ceftazidime-avibactam with aztreonam 14