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Both animal and human data suggest that AZACTAM (aztreonam for injection, USP) is rarely cross-reactive with other beta-lactam antibiotics and weakly immunogenic. Treatment with aztreonam can result in hypersensitivity reactions in patients with or without prior exposure. (See CONTRAINDICATIONS.)
Careful inquiry should be made to determine whether the patient has any history of hypersensitivity reactions to any allergens.
While cross-reactivity of aztreonam with other beta-lactam antibiotics is rare, this drug should be administered with caution to any patient with a history of hypersensitivity to beta-lactams (eg, penicillins, cephalosporins, and/or carbapenems). Treatment with aztreonam can result in hypersensitivity reactions in patients with or without prior exposure to aztreonam. If an allergic reaction to aztreonam occurs, discontinue the drug and institute supportive treatment as appropriate (eg, maintenance of ventilation, pressor amines, antihistamines, corticosteroids). Serious hypersensitivity reactions may require epinephrine and other emergency measures. (See ADVERSE REACTIONS.)
Clostridium difficile–associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including AZACTAM, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile.
C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin-producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over 2 months after the administration of antibacterial agents.
If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated.
Rare cases of toxic epidermal necrolysis have been reported in association with aztreonam in patients undergoing bone marrow transplant with multiple risk factors including sepsis, radiation therapy, and other concomitantly administered drugs associated with toxic epidermal necrolysis.
Prescribing AZACTAM in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.
In patients with impaired hepatic or renal function, appropriate monitoring is recommended during therapy.
If an aminoglycoside is used concurrently with aztreonam, especially if high dosages of the former are used or if therapy is prolonged, renal function should be monitored because of the potential nephrotoxicity and ototoxicity of aminoglycoside antibiotics.
The use of antibiotics may promote the overgrowth of nonsusceptible organisms, including Gram-positive organisms (Staphylococcus aureus and Streptococcus faecalis) and fungi. Should superinfection occur during therapy, appropriate measures should be taken.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Carcinogenicity studies with aztreonam have not been conducted using an intravenous route of administration. A 104-week rat inhalation toxicology study to assess the carcinogenic potential of aztreonam demonstrated no drug-related increase in the incidence of tumors. Rats were exposed to aerosolized aztreonam for up to 4 hours per day. Peak plasma levels of aztreonam averaging approximately 6.8 mcg/mL were measured in rats at the highest dose level.
Genetic toxicology studies performed with aztreonam in vitro (Ames test, mouse lymphoma forward mutation assay, gene conversion assay, chromosome aberration assay in human lymphocytes) and in vivo (mouse bone marrow cytogenetic assay) did not reveal evidence of mutagenic or clastogenic potential.
A two-generation reproduction study in rats at daily doses of 150, 600, or 2400 mg/kg given prior to and during gestation and lactation, revealed no evidence of impaired fertility. Based on body surface area, the high dose is 2.9-fold greater than the maximum recommended human dose (MRHD) for adults of 8 g per day. There was a slightly reduced survival rate during the lactation period in the offspring of rats that received the highest dose, but not in offspring of rats that received lower doses of aztreonam.
Pregnancy Category B
In pregnant women, aztreonam crosses the placenta and enters the fetal circulation.
Developmental toxicity studies in pregnant rats and rabbits with daily doses of aztreonam up to 1800 and 1200 mg/kg, respectively, revealed no evidence of embryotoxicity or fetotoxicity or teratogenicity. These doses, based on body surface area, are 2.2-and 2.9fold greater than the MRHD for adults of 8 g per day. A peri/postnatal study in rats revealed no drug-induced changes in any maternal, fetal, or neonatal parameters. The highest dose used in this study, 1800 mg/kg/day, is 2.2 times the MRHD based on body surface area.
There are no adequate and well-controlled studies of aztreonam on human pregnancy outcomes. Because animal reproduction studies are not always predictive of human response, aztreonam should be used during pregnancy only if clearly needed.
Aztreonam is excreted in human milk in concentrations that are less than 1% of concentrations determined in simultaneously obtained maternal serum; consideration should be given to temporary discontinuation of nursing and use of formula feedings.
The safety and effectiveness of intravenous AZACTAM have been established in the age groups 9 months to 16 years. Use of AZACTAM in these age groups is supported by evidence from adequate and well-controlled studies of AZACTAM in adults with additional efficacy, safety, and pharmacokinetic data from non-comparative clinical studies in pediatric patients. Sufficient data are not available for pediatric patients under 9 months of age or for the following treatment indications/pathogens: septicemia and skin and skin-structure infections (where the skin infection is believed or known to be due to H. influenzae type b). In pediatric patients with cystic fibrosis, higher doses of AZACTAM may be warranted. (See CLINICAL PHARMACOLOGY, DOSAGE AND ADMINISTRATION, and Clinical Studies.)
Clinical studies of AZACTAM did not include sufficient numbers of subjects aged 65 years and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.9-12 In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
In elderly patients, the mean serum half-life of aztreonam increased and the renal clearance decreased, consistent with the age-related decrease in creatinine clearance.1-4 Since aztreonam is known to be substantially excreted by the kidney, the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, renal function should be monitored and dosage adjustments made accordingly (see DOSAGE AND ADMINISTRATION: Renal Impairment in Adult Patients and Dosage in the Elderly).
AZACTAM contains no sodium.
1. Naber KG, Dette GA, Kees F, Knothe H, Grobecker H. Pharmacokinetics, in vitro activity, therapeutic efficacy, and clinical safety of aztreonam vs. cefotaxime in the treatment of complicated urinary tract infections. J Antimicrob Chemother 1986;17:517-527.
2. Creasey WA, Platt TB, Frantz M, Sugerman AA. Pharmacokinetics of aztreonam in elderly male volunteers. Br J Clin Pharmacol 1985;19:233-237.
3. Meyers BR, Wilkinson P, Mendelson MH, et al. Pharmacokinetics of aztreonam in healthy elderly and young adult volunteers. J Clin Pharmacol 1993;33:470474.
4. Sattler FR, Schramm M, Swabb EA. Safety of aztreonam and SQ 26,992 in elderly patients with renal insufficiency. Rev Infect Dis 1985;7 (suppl 4):S622S627.
9. Deger F, Douchamps J, Freschi E, et al. Aztreonam in the treatment of serious gram-negative infections in the elderly. Int J Clin Pharmacol Ther and Toxicol 1988;26:22-26.
10. Knockaert DC, Dejaeger E, Nestor L, et al. Aztreonam-flucloxacillin double betalactam treatment as empirical therapy of serious infections in very elderly patients. Age and Aging 1981;20:135-139.
11. Roelandts F. Clinical use of aztreonam in a psychogeriatric population. Acta Clin Belg 1992;47:251-255.
12. Andrews R, Fasoli R, Scoggins WG, et al. Combined aztreonam and gentamicin therapy for pseudomonal lower respiratory tract infections. Clin Therap 1994;16:236-252.
Last reviewed on RxList: 7/2/2013
This monograph has been modified to include the generic and brand name in many instances.
Additional Azactam Injection Information
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