ceftazidime pentahydrate: clinical use

Prescribing considerations

• Obtain microbiology samples and review susceptibility because coverage is mainly aerobic Gram-negative and resistance may involve ESBL or AmpC enzymes.
• Add antibacterial cover when likely pathogens are not all within its spectrum.
• Review renal function, age, infection site and severity when individualising treatment.
• Consider sodium from both the vial and diluent in patients requiring sodium restriction.
• Reassess prolonged treatment for superinfection with non-susceptible organisms.

Contraindications and cautions

• Hypersensitivity to ceftazidime, another cephalosporin or an excipient.
• Previous severe immediate hypersensitivity to another beta-lactam antibacterial, including penicillins, monobactams or carbapenems.
• Use caution after a non-severe reaction to another beta-lactam, in renal impairment, and where antibiotic-associated colitis is suspected.

Monitoring

• Renal function where clinically appropriate, particularly with renal impairment or nephrotoxic co-medication.
• Clinical response and microbiology results.
• Neurological status if renal clearance is reduced or confusion, myoclonus or seizures occur.
• Full blood count and liver tests during prolonged treatment or when clinically indicated.
• Bowel symptoms, skin reactions, administration sites and evidence of superinfection.
• A positive Coombs test may affect blood cross-matching; some urine glucose methods may give false-positive results.

Clinical pharmacology

A parenteral beta-lactam that inhibits bacterial cell-wall synthesis through penicillin-binding proteins. Protein binding is low, it is not metabolised, and most is eliminated unchanged by glomerular filtration. Activity relates to the time unbound concentrations remain above the organism's minimum inhibitory concentration.

Formulation and product differences

• The selected product is a white or pale-yellow powder containing ceftazidime pentahydrate and sodium carbonate.
• It contains 50 mg sodium per vial; sodium from the diluent must also be considered.
• Reconstitution releases carbon dioxide and creates positive vial pressure; small gas bubbles may be present.
• Sodium bicarbonate is not recommended as a diluent because ceftazidime is less stable in it.
• Prepared solution may be colourless to pale yellow without loss of potency when handled according to product instructions.

Injection

Route: Parenteral

Strengths: 500 mg, 1 g, 2 g