Efficacy and safety of aztreonam in the treatment of patients with renal failure

The efficacy and safety of aztreonam for treatment of gram-negative bacterial infections in patients with renal failure were evaluated in an open study. Thirty-nine patients (22-82 years old) with renal failure (chronic, 25; acute, 14) were treated for 40 severe gram-negative bacterial infections. All 41 gram-negative pathogens isolated were sensitive to aztreonam; the pathogens included Escherichia coli (12), Pseudomonas aeruginosa (8), Klebsiella species (7), Proteus species (7), Enterobacter species (5), Serratia marcescens (1), and Acinetobacter species (1). Complete cure (clinical and bacteriologic) was achieved in 31 (77.5%) of 40 infections and improvement (clinical improvement with or without bacteriologic cure) in four (10%). Bacterial eradication of 34 (82.9%) of the infecting pathogens was achieved. The only significant adverse effect noted was a slight, transient elevation in the level of serum transaminases in four patients (10%). Renal function of the patients improved with treatment. Levels of serum creatinine decreased from 3.79 +/- 2.84 to 3.30 +/- 2.52 mg/dL after treatment (P less than .002). It was concluded that aztreonam is effective and safe for the treatment of gram-negative bacterial infections in patients with renal failure.

Aztreonam monotherapy as prophylaxis in transurethral resection of the prostate: a multicenter study

The efficacy and safety of aztreonam in the prophylaxis of urinary tract infection following transurethral resection of the prostate (TURP) in patients with preoperatively sterile urine were studied in a multicenter trial including 300 patients at six Italian urology centers. The present report describes the first 192 patients enrolled in the protocol. Aztreonam or placebo was administered to each patient in three doses, which were given at the induction of anesthesia and 8 and 16 hours later. The development of bacteriuria was monitored by cultures of urine obtained before surgery, 3 days later, at removal of the bladder catheter, at discharge from the hospital, and at a follow-up visit 39-46 days after surgery. A febrile peak was observed for 6% of aztreonam-treated patients and for 20.9% of the placebo group (P less than .005), while bacteriuria was reported in 17.9% and 59.3% of these groups, respectively (P less than .001). From our data, TURP appears to be a clean-contaminated procedure requiring antibiotic prophylaxis, and aztreonam appears to reduce significantly the incidence of postoperative bacteriuria after this surgical procedure.

Tolerance to aztreonam in patients allergic to beta-lactam antibiotics

To evaluate the safe use of aztreonam (AZT) in patients allergic to penicillins and other beta-lactam antibiotics we studied 29 patients from a group of subjects allergic to beta-lactams, diagnosed by presenting systemic reactions after skin tests or challenge tests. Skin tests with benzylpenicilloyl (BPO), benzylpenicilloate, benzylpenicillin, ampicillin, amoxicillin, cephamandole and AZT, radioallergosorbent test (RAST) to BPO and AZT, RAST inhibition and challenge tests were performed. One patient was skin test-positive to AZT, another patient was RAST AZT-positive. IgE antibodies were specific to AZT as demonstrated by RAST inhibition studies with AZT coupled to epsilon-amino caproic acid. Nevertheless, AZT was unable to inhibit either a pool of sera or individual sera positive to BPO. Although all our 29 patients tolerated the administration of AZT (including those with skin test or RAST positive) and AZT appears to be safe in these subjects, this does not indicate that all beta-lactam-allergic patients tolerate AZT administration.

Aztreonam-flucloxacillin double beta-lactam treatment as empirical therapy of serious infections in very elderly patients

Aztreonam, the first monocyclic beta-lactam antibiotic with pure anti-Gram-negative activity, combined with flucloxacillin, a penicillinase resistant penicillin, was given as empirical treatment of 53 serious infections in very elderly people. Eighteen of the cases had positive blood cultures and 11 had a clinical picture of sepsis without positive blood cultures: Of 49 evaluable infections, 45 (92%) were cured. In 40% of the infections, antibiotic treatment could be narrowed after 72 hours to one antibiotic. Diarrhoea, mostly transitory, was the only side-effect. Aztreonam-flucloxacillin combination is a safe and effective empirical treatment regimen for serious infections in very elderly patients.

[Clinical evaluation of aztreonam for infections accompanying febrile neutropenic children with hematologic disorders and solid tumors. A cooperative study]

One hundred four children with infection accompanying hematologic disorders and solid tumors were treated with aztreonam (AZT) (120-150 mg/kg), either alone or in combination with one of the following drugs; cefmetazole (CMZ) (120-150 mg/kg), piperacillin (PIPC) (120-150 mg/kg), or amikacin (AMK) (5-10 mg/kg). The overall efficacy rate was 69.2%. Efficacy rates by regimen were as follows: AZT alone was 63.2%, AZT plus CMZ was 73.6%, AZT plus PIPC was 74.1% and AZT plus AMK was 20.0%. Efficacy rates in different types of infections were 53.2% for sepsis and suspected sepsis, 78.9% for pneumonia and respiratory tract infection, 93.1% for fever of undetermined origin and 55.6% for other infections. The efficacy rate was 71.3% in 94 patients in whom causative organisms were not identified and 50.0% in 10 patients in whom causative organisms were identified. Most of infections in which causative organisms were identified were caused by Gram-negative pathogens. The response rate among infections caused by Gram-negative bacilli was 50.0%. A combination of AZT and CMZ or PIPC was effective in 3 (100.0%) out of 3 patients in whom Escherichia coli was the causative organism. Efficacies classified according to different neutrophil counts were 59.3% for less than or equal to 100/microliters, 78.6% for 101-500/microliters and 82.4% for greater than or equal to 501/microliters. No significant adverse reactions were observed. These results indicated that combination of AZT and 2nd generation cephalosporins or penicillins were well tolerated and effective for infections complicated with accompanying hematologic disorders and solid tumors.

[Combination therapy with aztreonam and clindamycin on severe infections accompanying neutropenic patients with hematological disorders]

We studied effectiveness and safety of combination therapy of aztreonam (AZT) (2-6 g/day) and clindamycin (CLDM) (1,200-2,400 mg/day) on severe infections in neutropenic patients with hematological diseases. We administered AZT and CLDM to 250 consecutive patients and analyzed the results of a total of 212 cases for evaluation except 38 cases of exclusions and dropouts. Hematological malignancies constituted the dominating underlying diseases which represented 90.6% of all underlying diseases. The overall clinical efficacy of the combination therapy with AZT and CLDM was 65.6% and the following results were obtained for different categories: sepsis, 64.7%; suspected sepsis, 66.4%; and pneumonia 54.5%. Even severe patients with less than 100/microliters of neutrophil counts showed good responses with an efficacy rate at 57.4%. Side effects were observed in only 7 cases (2.8%). We concluded that the combination therapy with AZT and CLDM would be useful as empiric therapy against various infections in febrile neutropenic patients with hematological diseases.

Aztreonam

Aztreonam, the first commercially available monobactam, has a wide range of activity against aerobic gram-negative bacilli. It can be administered two to three hours daily because its half-life is 1.6 to 2 hours. Excellent blood and tissue concentrations are attained. The MIC of aztreonam against most Enterobacteriaceae is less than or equal to 2 micrograms/ml and against P aeruginosa less than or equal to 16 micrograms g/ml. Aztreonam has been used in a wide array of infections of the urinary tract and respiratory tract, blood, intra-abdominal and gynecologic infections and infections of the skin, bones and joints. As empiric therapy, aztreonam is usually combined with another antimicrobial agent active against anaerobes and/or aerobic gram-positive cocci until culture results are available. One exception is empiric therapy for gram-negative urinary tract infections in which aztreonam can be used initially as monotherapy against susceptible gram-negative pathogens. In general, the efficacy of aztreonam is equal or superior to that of the aminoglycosides. Adverse reactions to aztreonam are unusual, and it as been shown to be a poor hapten, permitting its administration to patients with proven allergy to the penicillins and cephalosporins. Aztreonam is a useful addition to the available antibiotics for treatment of gram-negative infections.

Immunogenicity and cross-allergenicity of aztreonam

Beta-lactams are responsible for more than half of the allergic drug reactions encountered in the hospital setting. Although most such reactions are mild, the potential for acute and life-threatening reactions cannot be underestimated when considering readministration of beta-lactam agents, such as the penicillins or cephalosporins, to persons who have previously exhibited sensitivity. In addition to concerns about possible allergic reactions to the beta-lactam antibiotics individually, considerable cross-reactivity has been demonstrated among such classes as the penicillins, the cephalosporins, and the imipenems, although it cannot yet be predicted on an individual basis. Early studies of the unique monocyclic beta-lactam--or monobactam--aztreonam, indicated that the new class demonstrated negligible cross-reactivity with the standard beta-lactams both experimentally and clinically.Further, aztreonam was associated with an extremely low (2 percent) incidence of immunologic drug reactions. Aztreonam also has been found to be well-tolerated by highly penicillin-allergic patients. Although further clinical study is indicated, data so far are encouraging. If it is confirmed that monobactams such as aztreonam are minimally cross-reactive, well-tolerated by subjects allergic to other beta-lactam antibiotics, and only weakly immunogenic, fewer allergic reactions may be associated with antimicrobial therapy in the future than have been seen with the other available beta-lactam antibiotic drugs.

[Pharmacokinetic and clinical evaluations of aztreonam monotherapy and aztreonam and ampicillin combination therapy in neonates and premature infants]

One-shot intravenous injection of aztreonam (AZT), a monobactam-class beta-lactam antibiotic, 20 mg/kg was administered to 4 neonates and 2 premature infants, a total of 6 cases, and plasma and urinary concentrations and urinary recovery rates were determined. Also, one-shot intravenous injection averaging 70.9 mg/kg/day of AZT alone was given to 0- to 43-day neonates and premature infants in b.i.d. to q.i.d. for an average of 8 days for the treatment (6 cases) and prophylaxis (11 cases) of infections. Furthermore, a combination therapy of AZT and ampicillin (ABPC) was applied to 0- to 79-day neonates and premature infants for the treatment (28 cases) and prophylaxis (18 cases) of infections. Average daily dosage of AZT 46.6 mg/kg was given by one-shot intravenous injection or by drip infusion in b.i.d. or t.i.d. for an average of 8 days. Average daily dosage of ABPC 78.6 mg/kg was given in the same daily frequency, route and average duration as AZT. Thus, clinical effects, prophylactic effects against infection, bacteriological effects as well as side effects and clinical laboratory test values were studied with the following results. 1. When AZT 20 mg/kg was administered to 1 case each of 6- and 7-day neonates by one-shot intravenous injection, the plasma concentrations were the highest at 5 minutes after the administration in both cases. Specifically, they were 62.9 and 72.7 micrograms/ml with AUCs of 216.6 and 231.6 micrograms.hr/ml and half-lives of 2.80 and 2.97 hours, respectively. When AZT 20 mg/kg was administered to 5- and 6-day premature infants by one-shot intravenous injection, the plasma concentrations were the highest at 15 minutes after administration in the former and 5 minutes in the latter, at values of 59.8 and 67.7 micrograms/ml, respectively. AUCs were 356.6 and 363.2 micrograms.hr/ml, respectively, and larger than AUCs of the above-mentioned neonates. Half-lives were 5.74 and 4.87 hours, respectively and longer than those of the above-mentioned neonates. When AZT 20 mg/kg was administered to 8- and 13-day neonates by one-shot intravenous injection, the plasma concentrations were the highest at 30 minutes after administration in the former and 5 minutes in the latter, at values of 43.4 and 76.9 micrograms/ml, respectively. AUCs were 202.9 and 189.8 micrograms.hr/ml, and 76.9 micrograms/ml, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

[Pharmacokinetics and clinical safety of aztreonam in neonates]

Clinical pharmacology and safety of aztreonam (AZT) in the neonatal period were investigated. The results obtained are summarized as follows. 1. Serum concentrations of AZT at 30 minutes after administration of 10 mg/kg were 22.1-32.2 micrograms/ml and those of 20 mg/kg 22.5-75.9 micrograms/ml. 2. Serum half-lives of AZT were 3.5-6.6 hours in 0-3 day-old neonates, and 2.0-4.0 hours in neonates 4 day-old or older. 3. A dose response was evident between the 10 mg/kg administration group and the 20 mg/kg group. 4. Urinary recovery rates of AZT in the first 6 hours after administration ranged between 17.8 and 69.9%. 5. No clinical side effects were observed in the administration of AZT alone (6 cases), or in combination with ampicillin (9 cases). Thrombocytosis was observed in 1 case as an abnormal laboratory finding, but it returned to normal within 1 week after the completion of AZT administration. 6. AZT had a potent antimicrobial activity against Gram-negative aerobes and hardly induced beta-lactamase. Furthermore, side effects were not observed in this study. Therefore, AZT is considered to be useful for the treatment of urinary tract infections and other serious infections caused by Gram-negative pathogens even in the neonatal period.

Aztreonam can safely be used in combination with cyclosporin without aggravating nephrotoxicity

The administration of antibiotics to renal transplant patients using cyclosporin can be difficult because of the risk of severe nephrotoxicity. An investigation was therefore carried out to determine whether aztreonam, a synthetic monocyclic beta-lactam antibiotic, can safely be combined with cyclosporin. In this retrospective study 68 renal transplant patients who received preoperative antibiotic prophylaxis consisting of aztreonam, ampicillin, and lincomycin were compared with 68 patients who received ceftazidime instead of aztreonam. Both groups were treated with cyclosporin and prednisolone and followed for 3 months. After transplantation 28.7% of the patients suffered from an acute renal failure and 1.5% had a wound infection. There were no significant differences between the two groups in acute renal failure, would infections, other infections, incidence of rejections, duration of admission, or graft survival. We therefore conclude that aztreonam can safely be administered together with cyclosporin. We also conclude that the combination of aztreonam, ampicillin, and lincomycin is a good preoperative antibiotic prophylaxis in renal transplant patients.

Clinical experience with aztreonam

Aztreonam, the first of the new class of monobactams, has a narrow and specific range of bactericidal activity; it is highly active against Gram-negative aerobic pathogens but is essentially inactive against Gram-positive or anaerobic bacteria. Several unique features indicate that aztreonam may provide an attractive choice for the treatment of serious Gram-negative infection in adults and children. Clinical study in adults has shown aztreonam to be highly effective against infections of the urinary and lower respiratory tracts, the musculoskeletal system and the female genitourinary tract. It also has proved useful in neutropenic patients, including those with cancer, and for treatment of bacterial peritonitis, gonorrhea, cellulitis and wound infections. Reported clinical and microbiologic cure rates have been comparable to those associated with traditional therapeutic approaches (85 to 100%). In the treatment of children with urinary tract infection as well as other types of infections, aztreonam therapy in a dosage of 30 mg/kg given every 6 to 8 hours was associated with satisfactory clinical and microbiologic cure rates. There appear to be specific clinical situations for which aztreonam may be an appropriate alternative to more toxic therapies, although comparative trials are needed to delineate the exact place of aztreonam in the armamentarium against bacterial infection.

The role of aztreonam in treatment of complicated urinary tract infections in children

Urinary tract infections are common among pediatric patients, occurring in approximately 2% of children within the first 5 to 10 years of life. Most urinary tract infections are uncomplicated and respond readily to treatment. However, complications may make treatment difficult and result in serious adverse sequelae. Several characteristics of aztreonam make it an attractive alternative to aminoglycosides and certain other antibiotics for the treatment of complicated urinary tract infections in children. It has been shown, for example, that the drug is highly active against most of the pathogenic organisms responsible for urinary tract infections in the pediatric population, as well as Pseudomonas aeruginosa and many less common, aminoglycoside- and cephalosporin-resistant Gram-negative bacteria. Aztreonam is widely distributed throughout the body and achieves potentially therapeutic concentrations in the kidneys and in urine for up to 24 hours after dosing. The efficacy and safety of this agent compare favorably with standard antibiotic agents. Aztreonam is associated with high rates of microbiologic and clinical cures, and the few side effects reported have been mild and transient.

Safety and toxicity profile of aztreonam

Aztreonam is the first monocyclic beta-lactam antibiotic released for clinical use. Extensive toxicity and safety data for aztreonam in animals, healthy volunteers and adult patients have been accumulated previously; recently these studies have been extended to children. Overall the incidence of adverse clinical reactions caused by aztreonam is similar to or lower than that caused by comparison drugs. There is no evidence that aztreonam causes significant ototoxicity or nephrotoxicity; biochemical and hematologic abnormalities are rarely significant. Compared with the broad spectrum cephalosporins, aztreonam causes less disruption of normal gastrointestinal flora and consequently a lower incidence of diarrhea. Aztreonam does not displace bilirubin from albumin and penetrates readily into cerebrospinal fluid. Because of negligible immunologic cross-reactivity with other beta-lactams, aztreonam has been safely administered to patients with IgE-mediated penicillin hypersensitivity. These data suggest that aztreonam should be safe and well-tolerated in infants and children with infections caused by susceptible Gram-negative bacteria.

Randomized clinical trial of aztreonam and aminoglycoside antibiotics in the treatment of serious infections caused by gram-negative bacilli

Aztreonam was compared with aminoglycoside antibiotics (tobramycin and amikacin) in a randomized, prospective, clinical trial in serious infections caused by gram-negative bacilli (GNB). A total of 43 evaluable patients with 47 infected sites were treated with aztreonam, and 41 evaluable patients were treated with aminoglycosides for 43 infections. Of patients treated with aztreonam, 17 were bacteremic, as were 12 of those treated with aminoglycosides. Clinical and microbiologic response rates were similar, except that only 5 of 11 patients with pneumonia were considered to be clinically cured with aminoglycoside therapy, while 5 of 6 patients with pneumonia treated with aztreonam were cured. Renal impairment was observed in 9 of 54 patients who received aminoglycoside antibiotics, but in only 2 of 53 patients treated with aztreonam. Hearing impairment developed in one patient treated with tobramycin. Transient elevations of serum transaminase levels occurred in 9 of 53 patients treated with aztreonam and in only 2 of 54 aminoglycoside-treated patients. Diarrhea and superinfection occurred with equal frequency in both groups. Serum concentrations of bactericidal activity could not be correlated with the outcome of therapy. Aztreonam appears to have comparable clinical efficacy with aminoglycoside antibiotics for the treatment of serious infections caused by aerobic and facultative GNB. Its use as a single agent for the treatment of serious lower respiratory infections caused by GNB warrants further evaluation.

Comparative multicenter study on efficacy and safety of aztreonam and gentamicin in prophylaxis of high-risk colorectal surgery

The usefulness of antibiotic prophylaxis in reducing the incidence of postoperative infections following colorectal surgery has been defined in many clinical studies. Since a single antibiotic agent covering all the potential pathogens (i.e. Gram-negative aerobes and anaerobes) is not currently available, a combination therapy is usually administered. The present study reports the preliminary results on comparative efficacy and safety of aztreonam and gentamicin (both combined with clindamycin) as short-term prophylaxis in colorectal surgery. Four hundred and fifty-four patients, out of 495 enrolled, were considered evaluable. Incidence of abdominal wound infections was significantly lower in the aztreonam-treated group (5.8% vs 12.5% - p less than or equal to .025). The incidence of perineal wound and abdominal infections, of fever, of need for postoperative antibiotics and the length of postoperative stay were lower in the monobactam group, even if none of these differences were statistically significant. Gram-negative aerobic microorganisms were more often isolated in infected patients from the gentamicin group. Side effects were minor and similar in the two groups. From these preliminary data, the aztreonam-clindamycin combination can be considered a major candidate to replace many of the presently available oral and parenteral regimens.

[Clinical reevaluation of aztreonam (AZT) on urinary tract infections]

The clinical effectiveness and safety of Aztreonam (AZT) were studied in 55 patients with complicated urinary tract infections. AZT was administered at a dose of 4 g/day for 5 days. The results as evaluated by the UTI criteria were excellent in 8 cases, moderate in 26 and poor in 21. The overall effectiveness rate was 61.8%. Out of 64 strains of bacteria isolated before treatment, 50 strains (78.0%) were eradicated by the treatment. Bacteriological eradication rates for gram negative rods and gram positive cocci were 79.6% and 66.7%, respectively. There were no obvious side effects, except for a temporary elevation of glutamic oxaloacetic transaminase, glutamic pyruvic transaminase alkalinephosphatase, and total bilirubin in some patients. The results indicate that AZT tablets are useful and safe for the treatment of complicated urinary tract infections.

Aztreonam in the treatment of bacterial meningitis

The monobactam aztreonam was used to treat 22 young patients with meningitis caused by gram-negative bacilli. Haemophilus influenzae was isolated from the CSF of 21 patients and Salmonella heidelberg from the CSF of 1. Dosages ranged from 100 to 200 mg/kg/day in 4 doses at 6-hour intervals. Minimal inhibitory concentrations were determined by the broth dilution method for all isolated strains, and values ranged from 0.05 to 2.0 micrograms/ml. Blood and CSF drug levels were determined by a microbiologic plate diffusion method, and mean values for CSF and blood were 1.4 and 14.9 micrograms/ml, respectively. The outcome was good in 21 patients; 1 patient died. Complications were mild; subdural effusion occurred in 6 cases and was managed clinically; asymptomatic hydrocephalus was seen in 4; seizure during the acute phase occurred in 6 cases; hypoacusis was noted in 2, and motor impairment was detected at the follow-up in 1 case. Aztreonam achieved good blood and CSF penetration and performed well in the treatment of 20 cases of H. influenzae meningitis and in the one case of S. heidelberg meningitis.

The clinical use of aztreonam

Aztreonam is the first monobactam antibiotic to be used clinically. It is highly resistant to beta-lactamases, and although its activity spectrum is similar to that of the aminoglycoside antibiotics, it has no effect on gram-positive bacteria. The current study was undertaken to determine the efficacy of aztreonam in treating gram-negative infections caused by multiresistant microorganisms in patients with known sensitivity to penicillins and cephalosporins. Sixty-six patients presented with urinary tract infection (UTI) and 30 with respiratory tract infection (RTI). All patients received aztreonam, between 4 and 6 g/day in divided doses for 10-14 days. Cure was achieved in 59 (89.3%) patients with UTI; in the group with RTI, 20 patients were cured and 4 improved with treatment. Tolerance to the drug was good in both groups, and in no instance did side effects necessitate modification of the dosing regimen.

[Clinical efficacy of aztreonam in patients with complicated urinary tract infections]

Aztreonam (AZT) (2 g daily) was intravenously administered for 5 to 7 days to 65 patients with complicated urinary tract infections (UTI). Ninety one organisms were isolated from these patients' urine. Among them 66 organisms were eliminated following AZT administration. The elimination rate for Gram negative organisms was 94.7% and that for Gram positive organisms was 33.3%. Thirty one organisms appeared newly by the replacement of organisms. Among them, 12 organisms were E. faecalis. The efficacy rate of AZT in single infection and in mixed infection was 55.8% and 13.7%, respectively. The overall clinical efficacy rate of AZT in the present study was 41.5%. As side effects, skin rash and itching were observed in 3 patients and slight elevations in blood chemistry were observed in 10 patients. The results indicate that AZT is an effective drug for the treatment of patients with complicated UTI, especially those caused by Gram negative organisms.