Cayston (aztreonam lysine)

Dosage and route of administration of aztreonam should be determined by the type and severity of infection, susceptibility of the causative organism, and patient condition. Do not use dosages lower than those usually recommended.

For most infections, continue parenteral aztreonam treatment for at least 48 hours after the patient becomes asymptomatic or evidence of eradication of the infection has been obtained. Persistent infections may require several weeks of treatment.

Administer aztreonam by IV injection or infusion, or by deep IM injection.

Aztreonam also is administered by oral inhalation via nebulization in patients with cystic fibrosis.

Aztreonam has been administered intraperitoneally+ in dialysis fluid.

No dosing information is available for this tab.

Drug interactions reported are based on parenteral aztreonam. Formal drug interaction studies have not been conducted to date using aztreonam administered by oral inhalation via nebulization.

Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

Antibiotics/Fecal Microbiota

SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

MECHANISM OF ACTION: Fecal microbiota is a suspension of live bacteria, which may be compromised by concurrent use of antibiotics.(1)

CLINICAL EFFECTS: Antibiotics may decrease the effectiveness of fecal microbiota.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Antibiotics should not be used concurrently with fecal microbiota. Antibacterial treatment should be completed for 24 to 72 hours before initiating treatment with fecal microbiota. Do not use antibiotics for up to 8 weeks after fecal microbiota.(1)

DISCUSSION: Antibiotics may compromise the effectiveness of fecal microbiota.

Antibiotics/Fecal Microbiota Spores

SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

MECHANISM OF ACTION: Fecal microbiota spores is a suspension of live bacterial spores, which may be compromised by concurrent use of antibiotics.(1)

CLINICAL EFFECTS: Antibiotics may decrease the effectiveness of fecal microbiota spores.(1)

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Antibiotics should not be used concurrently with fecal microbiota spores. Antibacterial treatment should be completed for 2 to 4 days before initiating treatment with fecal microbiota spores.(1)

DISCUSSION: Antibiotics may compromise the effectiveness of fecal microbiota spores.

Antimicrobials/Live Typhoid Vaccine

SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.

MECHANISM OF ACTION: The antimicrobial may be active against the organism in the live-vaccine. Antimicrobial therapy may prevent the vaccine organism from replicating enough to trigger an immune response.(1)

CLINICAL EFFECTS: Vaccination may be ineffective.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: Do not give oral typhoid vaccine until 72 hours after the last dose of antimicrobial. If possible, to optimize vaccine effectiveness, do not start antibacterial drugs for 72 hours after the last dose of oral typhoid vaccine. A longer interval should be considered for long-acting antimicrobials, such as azithromycin.(3)

DISCUSSION: Because antimicrobial therapy may prevent sufficient vaccine-organism replication to generate an immune response, the manufacturer of live-attenuated typhoid vaccine and the Centers for Disease Control (CDC) state that the vaccine should not be administered to patients receiving antimicrobial therapy.(1-3)

There are no severe interactions for this drug.

There are no moderate interactions for this drug.

*Known hypersensitivity to aztreonam or any component of the formulation.

There are no contraindication contraindications for this drug.

There are no severe contraindications for this drug.

• Bronchospastic pulmonary disease

Adverse effects reported with IV or IM aztreonam are similar to those reported with other beta-lactam antibiotics, and the drug generally is well tolerated. Adverse effects have been reported in 7% or less of patients receiving parenteral aztreonam and have required discontinuance in about 2% of patients.

Rare or Very Rare

• Dyspnea
• Facial edema
• Skin rash
• Throat constriction

More Frequent

• Acute abdominal pain
• Chest discomfort
• Cough
• Fever
• Nasal congestion
• Vomiting
• Wheezing

Less Frequent

• Bronchospastic pulmonary disease
• Sore throat

Rare or Very Rare

• Arthralgia
• Arthritis

No enhanced messaging available.

The manufacturers state that use of IV aztreonam in children 9 months of age or older is supported by evidence from adequate and well-controlled studies in adults and additional efficacy, safety, and pharmacokinetic data from noncomparative clinical studies in pediatric patients. However, data are insufficient to date to determine safety and efficacy of IV aztreonam in pediatric patients 9 months of age or older for the treatment of septicemia or skin and skin structure infections (when skin infection suspected or known to be caused by Haemophilus influenzae type b). In addition, the manufacturers state that data are insufficient to date to evaluate IM administration of aztreonam in pediatric patients or use of the drug in pediatric patients with impaired renal function.

In clinical studies evaluating parenteral aztreonam in pediatric patients, discontinuance of the drug because of adverse effects was required in less than 1% of patients. Rash, diarrhea, and fever have been reported in 1-4.3% of pediatric patients. In pediatric patients receiving IV aztreonam, pain was reported in 12% and erythema, induration, or phlebitis were reported in 0.9-2.9% of patients overall; in US patients, pain occurred in 1.5% and other local reactions occurred in about 0.5%. Eosinophilia, neutropenia, or increased platelet count has been reported in 6.3, 3.2, or 3.6% of pediatric patients, respectively, and increased serum AST, ALT, or serum creatinine has been reported in 3.8-6.5%. In US pediatric studies, neutropenia (absolute neutrophil count less than 1000/mm3) occurred in 11.3% of patients younger than 2 years of age receiving aztreonam in a dosage of 30 mg/kg every 6 hours and increased serum AST and ALT (greater than 3 times the upper limit of normal) occurred in 15-20% of patients 2 years of age or older receiving a dosage of 50 mg/kg every 6 hours. It is unclear whether the increased frequency of these adverse effects was related to increased severity of illness in the patients or aztreonam dosage administered.

Aztreonam has been used IM or IV in a limited number of neonates and infants as young as 1 month of age+ without unusual adverse effects.

Safety and efficacy of aztreonam administered by oral inhalation via nebulization have not been established in pediatric patients younger than 7 years of age. The drug has been used by oral inhalation via nebulization for the treatment of newly acquired Ps. aeruginosa respiratory tract infections in a limited number of cystic fibrosis patients 3 months through 6 years of age+ without unusual adverse effects. In clinical trials evaluating aztreonam inhalation therapy in cystic fibrosis patients 7 years of age or older, pyrexia was reported more frequently in pediatric patients than in adults.

There are no adequate and controlled studies to date using parenteral aztreonam or aztreonam administered by oral inhalation via nebulization in pregnant women. Use parenteral or orally inhaled aztreonam during pregnancy only when clearly needed. Aztreonam crosses the placenta in pregnant women and enters fetal circulation.

No evidence of embryotoxicity, fetotoxicity, or teratogenicity was found in reproduction studies in pregnant rats and rabbits using daily parenteral aztreonam dosages up to 1.8 and 1.2 g/kg, respectively; these aztreonam dosages were 2.2- and 2.9-fold greater than the maximum recommended human dosage (MRHD) based on body surface area. There was no evidence of drug-induced changes in any maternal, fetal, or neonatal parameters when parenteral aztreonam was used in a perinatal/postnatal study in rats; the highest dosage used in this study (1.8 g/kg daily) was 2.2 times the MRHD based on body surface area. However, in a 2-generation reproduction study in rats using parenteral aztreonam dosages up to 2.4 g/kg daily (2.9-fold greater than the MRHD), there was a slightly reduced survival rate during the lactation period in offspring of rats that received the highest dosage, but not in offspring of rats that received lower dosages.

Because aztreonam is distributed into milk in low (<1%) concentrations following parenteral administration and because safety of aztreonam in neonates has not been fully evaluated to date, consider temporary discontinuance of nursing if parenteral aztreonam is used in lactating women.

Aztreonam 75 mg administered by oral inhalation via nebulization in lactating women produced peak plasma concentrations approximately 1% of peak plasma concentrations reported following a 500-mg IV dose of the drug. Systemic absorption of aztreonam following inhaled administration is likely minimal, but the effects on the infant or on milk production are unknown.

Select dosage in geriatric patients with caution because of the greater frequency of decreased hepatic, renal, and/or cardiac function and of concomitant disease and drug therapy observed in these patients. Aztreonam is substantially eliminated by the kidneys and the risk of adverse reactions may be greater in patients with impaired renal function. Because geriatric patients are more likely to have renal impairment, monitor renal function and make appropriate dosage modifications if necessary.

Clinical studies evaluating IV or IM aztreonam or aztreonam administered by oral inhalation via nebulization did not include sufficient numbers of patients 65 years of age and older to determine whether they respond differently than younger patients. Other reported clinical experience with parenteral aztreonam has not identified differences in responses between geriatric patients and younger adults.

Aztreonam is substantially eliminated by the kidneys, and the risk of adverse effects may be greater in those with impaired renal function. Because geriatric patients are more likely to have reduced renal function, select IV or IM dosage of aztreonam with caution and monitor renal function.