Mechanism of effect
Ceftazidime is a bactericidal agent that acts by inhibition of bacterial cell wall synthesis. Ceftazidime has activity in the presence of some beta-lactamases, both penicillinases and cephalosporinases, of Gram-negative and Gram positive bacteria.
Pharmacodynamic
Ceftazidime is a bactericidal agent that acts by inhibition of bacterial cell wall synthesis.
Pharmacokinetics
The absorption and elimination of Ceftazidime were directly proportional to the size of the dose. The half-life following IV administration was approximately 1.9 hours. Less than 10% of Ceftazidime was protein bound. The degree of protein binding was independent of concentration. There was no evidence of accumulation of Ceftazidime in the serum in individuals with normal renal function following multiple IV doses of 1 and 2 g every 8 hours for 10 days.
The presence of hepatic dysfunction had no effect on the pharmacokinetics of Ceftazidime in individuals administered 2 g intravenously every 8 hours for 5 days. Therefore, a dosage adjustment from the normal recommended dosage is not required for patients with hepatic dysfunction, provided renal function is not impaired.
Approximately 80% to 90% of an IV dose of Ceftazidime is excreted unchanged by the kidneys over a 24-hour period. After the IV administration of single 500 mg or 1 g doses, approximately 50% of the dose appeared in the urine in the first 2 hours. An additional 20% was excreted between 2 and 4 hours after dosing, and approximately another 12% of the dose appeared in the urine between 4 and 8 hours later. The elimination of Ceftazidime by the kidneys resulted in high therapeutic concentrations in the urine.
The mean renal clearance of Ceftazidime was approximately 100 mL/min. The calculated plasma clearance of approximately 115 mL/min indicated nearly complete elimination of Ceftazidime by the renal route. Administration of probenecid before dosing had no effect on the elimination kinetics of Ceftazidime. This suggested that Ceftazidime is eliminated by glomerular filtration and is not actively secreted by renal tubular mechanisms.
Since Ceftazidime is eliminated almost solely by the kidneys, its serum half-life is significantly prolonged in patients with impaired renal function. Consequently, dosage adjustments in such patients as described in the DOSAGE AND ADMINISTRATION section are suggested.
Drug indications
Pneumonia , Sinusitis , Intraabdominal Infection , urinary tract infection , PyelonephritisDosage
Adults :
2 g IV every 8 hours for 14 days, depending on the nature and severity of the infection
Peditric Infections :
30 to 50 mg/kg IV every 8 to 12 hours
The higher dose range should be reserved for patients with meningitis, cystic fibrosis, or immunocompromised patients.
Drug contraindications
severe hypersensitivity reactionsSide effects
nausea , vomiting , Diarrhea , fever , Creatinine increased , Asthma , skin rush , Abdominal pains , Leukopenia , thrombocytopenia , increased liver enzymes in the blood , vaginitisInteractions
Furosemide , Endometrine , cholera vaccine live , Typhoid vaccine (live), oral , Aminohippurate SodiumAlerts
High and prolonged serum Ceftazidime concentrations can occur from usual dosages in patients with transient or persistent reduction of urinary output because of renal insufficiency. The total daily dosage should be reduced when Ceftazidime is administered to patients with renal insufficiency
Points of recommendation
Patients should be counseled that antibacterial drugs , including Ceftazidime for injection, should only be used to treat bacterial infections . They do not treat viral infections (e.g., the common cold). When Ceftazidime for injection is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed.
Skipping doses or not completing the full course of therapy may: (1) decrease the effectiveness of the immediate treatment, and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by Ceftazidime for injection or other antibacterial drugs in the future.
Diarrhea is a common problem caused by antibiotics which usually ends when the antibiotic is discontinued. Sometimes after starting treatment with antibiotics , patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as 2 or more months after having taken the last dose of the antibiotic. If this occurs, patients should contact their physician as soon as possible.
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