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PubMed2002

Double-blind, placebo-controlled study comparing the effect of azithromycin with clarithromycin on oropharyngeal and bowel microflora in volunteers.

The purpose of this double-blind study was to assess the effect of azithromycin and clarithromycin on oral and fecal microflora. Bacterial species from fecal samples and throat washes from healthy volunteers were identified and quantified before, during and after receipt of either placebo ( n=6), azithromycin (500 mg once daily for 3 days; n=6) or clarithromycin (500 mg twice daily for 7 days; n=6). In both antibiotic groups, the changes in oropharyngeal aerobic microflora following antibiotic administration were minor. Antibiotics neither changed the bacterial load of Streptococcus spp. compared with placebo, nor did macrolide-resistant streptococci emerge. In the fecal aerobic microflora, the number of organisms of the family Enterobacteriaceae decreased slightly after antibiotic administration in both the clarithromycin and the azithromycin groups, but levels normalized by day 21 after therapy. No colonization with nonfermenters or Clostridium difficile was seen, and the total number of anaerobic bacteria was not affected in any study group. In conclusion, there were no significant differences between azithromycin and clarithromycin in their effect on human oropharyngeal and intestinal microflora, nor was the use of these antibiotics associated with colonization by resistant, gram-positive organisms or overgrowth of opportunistic microorganisms.

Adolescent↗
PubMed1996

Hyperactivity of cathepsin B and other lysosomal enzymes in fibroblasts exposed to azithromycin, a dicationic macrolide antibiotic with exceptional tissue accumulation.

Azithromycin accumulates in lysosomes where it causes phospholipidosis. In homogenates prepared by sonication of fibroblasts incubated for 3 days with azithromycin (66 microM), the activities of sulfatase A, phospholipase A1, N-acetyl-beta-hexosaminidase and cathepsin B increased from 180 to 330%, but not those of 3 non-lysosomal enzymes. The level of cathepsin B mRNA was unaffected. The hyperactivity induced by azithromycin is non-reversible upon drug withdrawal, prevented by coincubation with cycloheximide, affects the Vmax but not the Km, and is not reproduced with gentamicin, another drug also causing lysosomal phospholipidosis. The data therefore suggest that azithromycin increases the level of lysosomal enzymes by a mechanism distinct from the stimulation of gene expression but requiring protein synthesis, and is not in direct relation to the lysosomal phospholipidosis.

Animals↗
PubMed1993

Randomised controlled trial of single-dose azithromycin in treatment of trachoma.

Blindness due to trachoma is a serious public health issue world wide. The currently recommended treatment of active trachoma with repeated doses of tetracycline eye ointment has many disadvantages. The new azalide antibiotic azithromycin is effective as a single oral dose in the chemotherapy of genital Chlamydia trachomatis infections, and we have assessed its efficacy for trachoma treatment. We carried out a randomised single-blind comparison of azithromycin (a single oral dose of 20 mg/kg) with conventional treatment (6 weeks of topical tetracycline plus erythromycin for severe cases) in two villages with endemic trachoma in The Gambia. The patients were followed up for 26 weeks from the start of treatment by an observer unaware of treatment allocation. By 6 months' follow-up, trachoma had resolved in 76 (78%) of 97 subjects who received azithromycin compared with 70 (72%) of 97 who were treated conventionally (95% CI for difference -6% to 18%). Compliance with both treatments was good, but that for conventional treatment could probably not be achieved outside the research setting. There were no significant differences in treatment effect, baseline characteristics, or re-emergent disease between the treatment groups. Azithromycin was well tolerated. As a systemic treatment effective in a single dose it has important potential for trachoma control.

Administration, Oral↗
PubMed1994

Validation of NCCLS macrolide (azithromycin, clarithromycin, and erythromycin) interpretive criteria for Haemophilus influenzae tested with the Haemophilus test medium. National Committee for Clinical Laboratory Standards.

Some recently marketed macrolide antimicrobial agents possess physiochemical, antimicrobial, and pharmacokinetic advantages that enable their wider clinical use against Haemophilus influenzae infections. A five-laboratory study assessed the validity of existing or proposed azithromycin, clarithromycin, and erythromycin interpretive criteria for tests with H. influenzae isolates. National Committee for Clinical Laboratory Standards (NCCLS) methods, criteria, and quality-control guidelines were used. A total of 350 H. influenzae strains were processed, including fresh clinical isolates (250 strains) and replicate tests of 100 stock cultures sampling strains isolated from 1984 to 91. Azithromycin interpretive criteria (susceptible at < or = 4 micrograms/ml, > or = 12 mm) produced a 99.8% absolute agreement between the minimum inhibitory concentrations and disk diffusion results (0.2% false-susceptible error). Clarithromycin breakpoint criteria (susceptible at < or = 8 micrograms/ml, > or = 13 mm; and resistant at > or = 32 micrograms/ml, < or = 10 mm) produced high minor interpretive error, but < or = 1% combined false-susceptible and false-resistant discrepancies. Erythromycin interpretive guidelines were initially proposed for susceptible at < or = 0.5 microgram/ml, > or = 26 mm. This categorizes nearly all H. influenzae strains as resistant to this older macrolide. The NCCLS should consider the proposed erythromycin criteria for publication in appropriate tables, and a class drug should also be selected (azithromycin) that would best predict macrolide-class susceptibility for those agents indicated by the US Food and Drug Administration for H. influenzae infection chemotherapy (azithromycin and clarithromycin). No serious interpretive problems were observed with the current NCCLS criteria using Haemophilus test medium.

Anti-Bacterial Agents↗
PubMed2004

Studies on electrochemical oxidation of azithromycin and its interaction with bovine serum albumin.

A novel nanoparticle film modified electrode has been constructed using a glassy carbon electrode (GCE) coated with a carbon nanotube-dihexadecylphosphate (DHP) film. This modified electrode exhibits an enhanced effectiveness for the oxidation of azithromycin. A method is also described for the evaluation of azithromycin-bovine serum albumin (BSA) interaction. The electrochemical behavior of azithromycin as well as its interaction with BSA at this nanoparticle film electrode has been investigated by cyclic voltammetry, linear sweep voltammetry, differential pulse voltammetry and chronocoulometry. The binding number and association constant between azithromycin and bovine serum albumin have been obtained.

Animals↗
PubMed2003

Ultrasensitive assay of azithromycin in medicine and bio-fluids based on its enhanced luminol-H(2)O(2) chemiluminescence reaction using flow injection technique.

A simple flow injection chemiluminescence method with synergistic enhancement has been investigated for the rapid and sensitive determination of azithromycin. The synergistic action was significant in the chemiluminescence system of luminol-hydrogen peroxide with azithromycin as an enhancer. The enhanced chemiluminescence intensity was linear with the concentration of azithromycin over the range from 0.1 pg x mL(-1) to 1.0 ng x mL(-1) (r(2=)0.9988) with a detection limit (3sigma) of 0.04 pg x mL(-1). At a flow rate of 2.0 mL x min(-1), a complete analytical process could be performed within 0.5 min, including sampling and washing, with a relative standard deviation of less than 3.0%. The proposed method was applied successfully in the assay of azithromycin in pharmaceutical preparations, human urine and serum without any pre-treatment procedure.

Anti-Bacterial Agents↗
PubMed2005

Azithromycin extraction from municipal wastewater and quantitation using liquid chromatography/mass spectrometry.

Azithromycin is a broad spectrum antimicrobial agent that is approved in the United States for use in humans. Due to azithromycin's low rate of metabolism it is likely to be found in wastewater treatment plants, where its broad spectrum of antimicrobial activity could lead to development of resistance in bacteria. A liquid-liquid extraction using K2CO3 and methyl-t-butyl ether (MTBE) was used to extract azithromycin from 10 ml aliquots of wastewater. Liquid chromatography was performed using a Luna C18(2) (30 mm x 2.0 mm) column with a mass spectrometer friendly mobile phase containing 50:24:2:24 acetonitrile, methanol, tetrahydrofuran, and 0.04 M ammonium hydroxide. The mass spectrometer used an electrospray source with positive ionization and an ion trap detector. A linear standard curve from 5 to 200pg/ml was validated and used to quantitate azithromycin in wastewater.

Azithromycin↗
PubMed2005

A comparison of 5 days of therapy with cefdinir or azithromycin in children with acute otitis media: a multicenter, prospective, single-blind study.

BACKGROUND: Short-course therapy for acute otitis media (AOM) improves adherence and may reduce secondary bacterial resistance. METHODS: In this multicenter, prospective, investigator-blinded study, patients between the ages of 6 months and 6 years with a clinical diagnosis of AOM were randomized to receive cefdinir oral suspension 7 mg/kg q12h for 5 days or azithromycin oral suspension 10 mg/kg once daily on day 1 and 5 mg/kg once daily on days 2 through 5. Clinical response was assessed at the end-of-therapy (EOT) visit (days 7-9) and the follow-up visit (days 20-25). RESULTS: Three hundred fifty-seven patients were enrolled in the study. The treatment groups were similar at baseline with respect to demographic characteristics (mean [SD] age, 3.0 [1.7] years; 55% male), incidence of bilateral AOM (45%), and presenting signs and symptoms. The majority of evaluable children (77%) had previously received conjugated heptavalent pneumococcal vaccine (PCV7) against Streptococcus pneumoniae. At the EOT visit, clinical cure rates were comparable for cefdinir and azithromycin (87% [151/174] and 85% [149/176], respectively; 95% CI, -5.5 to 9.8). In addition, clinical cure rates at the EOT visit in the children who had been vaccinated with PCV7 were comparable between cefdinir and azithromycin (86% vs 83%; 95% CI, -6.5 to 11.8). No significant difference in clinical cure rates was observed at the follow-up visit (76% and 86%; 95% CI, -18.9 to 0.0). Parental satisfaction was similar between treatment groups with regard to ease of use, taste, compliance, health care resource utilization, and missed days of work and day-care. Both antibiotics were well tolerated; diarrhea and abnormal stools were the most common antibiotic-related adverse events (< or = 7% each). CONCLUSIONS: Short courses (5 days) of therapy with cefdinir or azithromycin were comparable in these children with AOM based on clinical end points, parental preferences, and health care utilization.

Acoustic Impedance Tests↗
PubMed2005

Bioavailability of two oral formulations of azithromycin 500 mg: a randomized, open-label, two-period crossover comparison in healthy Mexican adult subjects.

BACKGROUND: Azithromycin is related to erythromycin but is more active against gram-negative bacteria and less active against streptococci and staphylococci compared with erythromycin. For these reasons, and because of convenience of dosing (QD for 3 days), azithromycin is widely used in Mexico. Although several generic formulations of azithromycin are available in Mexico, information concerning the bioavailability of each formulation in the Mexican population is not available. OBJECTIVE: The aim of this study was to compare the bioavailability and tolerability of 2 oral formulations of azithromycin 500 mg used in Mexico: Macrozit (trademark of Laboratorios Liomont, S.A. de C.V., Mexico City, Mexico; test formulation) and Azitrocin (trademark of Pfizer, S.A. de C.V., Mexico City, Mexico; reference formulation). METHODS: This 2 x 2, crossover, randomized, open-label study was conducted at the Department of Pharmacology and Toxicology, Universidad Autóma de Nuevo Leon, Monterrey, Mexico. Eligible subjects were healthy volunteers of either sex and with the following characteristics: age > or =19 to 25 years, weight 54 to 77 kg, and height 159 to 177 cm. Subjects were randomly assigned to receive Macrozit followed by Azitrocin, or vice versa, with a 3-week washout period between doses. After a 12-hour (overnight) fast, subjects received a single, 500-mg dose of each formulation. For analysis of pharmacokinetic properties, including C(max), AUC(0-t), and AUC(0-infinity), blood samples were drawn at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 12, 24, 48, 72, 96, and 120 hours after dosing. The formulations were considered bioequivalent if the logarithm (ln)-transformed ratios of C(max) and AUC were within the predetermined equivalence range of 80% to 125% and if P < or = 0.05 for the 90% CIs. Tolerability was assessed by monitoring and subject interview regarding the potential presence of adverse events (AEs). RESULTS: Twenty-eight subjects were enrolled in the study; 27 completed it (14 men, 13 women; mean age, 21.7 years). Fourteen subjects received the test formulation first. No period or sequence effect was observed. The 90% CIs for the corresponding ratios of C(max), AUC(0-t), and AUC(0-infinity) were 80.67 to 107.21, 91.39 to 107.59, and 90.61 to 106.19 (all, P < 0.05). Similar results were found for data without a logarithmic transformation. No AEs were found throughout the study. CONCLUSIONS: In this small study in healthy Mexican volunteers, a single, 500-mg dose of Macrozit was found to be bioequivalent to that of Azitrocin based on the rate and extent of absorption. Both formulations were well tolerated.

Administration, Oral↗
PubMed2005

Long-term azithromycin use for treatment of bronchiolitis obliterans syndrome in lung transplant recipients.

Short-term improvement in lung function was observed in 5 of 6 lung transplant recipients with bronchiolitis obliterans syndrome (BOS) who were treated with oral azithromycin. We assessed the long-term effect (mean duration 10 months) of treatment with oral azithromycin in 11 lung transplant recipients with BOS. Mean forced expiratory volume in 1 second (FEV1) was 40 +/- 9% at initiation of azithromycin treatment, 39 +/- 10% after 1 month, 39 +/- 12% after 4 months, 38 +/- 10% after 7 months and 38 +/- 10% after 10 months, respectively (statistically non-significant for all data). We conclude that long-term administration with oral azithromycin does not reverse BOS in lung transplant recipients, but may slow progression of the disease.

Administration, Oral↗
PubMed2004

Azithromycin versus comparative therapy for the treatment of community acquired pneumonia.

A 3-day course of azithromycin was compared with the 10 days of other antibiotics, which general practitioners routinely use as therapy for community acquired pneumonia (CAP). The study was a prospective open labelled, randomised, multicentre, comparative study from five family clinics. Patients with clinical and radiological evidence of pneumonia were included. The pneumonia resolved in 98.4% (61/62) of patients treated with azithromycin and in 87% (40/46) of patients treated with other antibiotics (P < 0.017). Restitution of normal function at home (2.3 +/- 1.2 and 4.3 +/- 2.6 days) and return to work (3.4 +/- 2.0 and 5.5 +/- 3.1 days) was more rapid among the group treated with azithromycin ( P < 0.001). Three days of azithromycin was more convenient and cost effective than the comparators used to treat pneumonia.

Adolescent↗
PubMed2005

Treatment of acute exacerbation of severe-to-very severe COPD with azithromycin in patients vaccinated against Streptococcus pneumoniae.

Sixty-five consecutive eligible adult patients, who were treated as outpatients for stable severe-to-very severe COPD, were enrolled in the study. All of them received 23-valent pneumococcal capsular polysaccharide vaccine intramuscularly. Patients were seen monthly, as well as whenever they had symptoms suggestive of an exacerbation, at our outpatient clinic. Eighteen out of 65 patients suffered from acute exacerbation (AECOPD). Three of these patients presented two episodes of AECOPD. Patients with an acute exacerbation of COPD received azithromycin 500 mg/day once daily for 3 days and a short course of oral prednisolone 25 mg/die. In 16 cases, a single species was isolated, while in the remaining 5 cases at least two species were recovered. Clinical cure or improvement at the end of therapy (3-5 days post-therapy) was reported in 17 episodes of AECOPD with no relapse at the late post-therapy (10-14 days after the completion of treatment). Bacteriologic eradication or presumptive eradication rates at the end of therapy were 86% (24 out of 28 isolates). Azithromycin eradicated all isolates of Haemophilus influenzae, Moraxella catarrhalis, H. parainfluenzae, Klebsiella pneumoniae, and Klebsiella spp. isolated at baseline. Eradication of Sta aureus occurred in 1 of 3 isolates whereas azithromycin was unable to eradicate Pseudomonas aeruginosa isolates. Our data seem to indicate that pneumococcal vaccination reduces the possibility that an AECOPD is caused by Streptococcus pneumoniae. This finding allows the use of antibiotics such as azithromycin, which, otherwise, should be avoided because of resistances.

Acute Disease↗
PubMed2004

Azithromycin and erythromycin ameliorate the extent of colonic damage induced by acetic acid in rats.

Ulcerative colitis is a common inflammatory bowel disease (IBD) of unknown etiology. Recent studies have revealed the role of some microorganisms in the initiation and perpetuation of IBD. The role of antibiotics in the possible modulation of colon inflammation is still uncertain. In this study, we evaluated the effects of two macrolides, namely azithromycin and erythromycin, at different doses on the extent and severity of ulcerative colitis caused by intracolonic administration of 3% acetic acid in rats. The lesions and the inflammatory response were assessed by histology and measurement of myeloperoxidase (MPO) activity, nitric oxide synthetase (NOS) and tumor necrosis factor alpha (TNFalpha) in colonic tissues. Inflammation following acetic acid instillation was characterized by oedema, diffuse inflammatory cell infiltration and necrosis. Increase in MPO, NOS and TNFalpha was detected in the colonic tissues. Administration of either azithromycin or erythromycin at different dosage (10, 20 and 40 mg/kg orally, daily for 5 consecutive days) significantly (P < 0.05) reduced the colonic damage, MPO and NOS activities as well as TNFalpha level. This reduction was highly significant with azithromycin when given at a dose of 40 mg/kg. It is concluded that azithromycin and erythromycin may have a beneficial therapeutic role in ulcerative colitis.

Acetic Acid↗
PubMed2002

Azithromycin modulates neutrophil function and circulating inflammatory mediators in healthy human subjects.

Effects on human neutrophils and circulating inflammatory mediators were studied in 12 volunteers who received azithromycin (500 mg/day, p.o.) for 3 days. Blood was taken 1 h before treatment, 2.5, 24 h and 28 days after the last dose. An initial neutrophil degranulating effect of azithromycin was reflected in rapid decreases in azurophilic granule enzyme activities in cells and corresponding increases in serum. The oxidative response to a particulate stimulus was also acutely enhanced. These actions were associated with high plasma and neutrophil drug concentrations. A continuous fall in chemokine and interleukin-6 serum concentrations, within the non-pathological range, accompanied a delayed down-regulation of the oxidative burst and an increase in apoptosis of neutrophils up to 28 days after the last azithromycin dose. Neutrophils isolated from blood at this time point still contained detectable drug concentrations. Acute neutrophil stimulation could facilitate antibacterial effects of azithromycin, while delayed, potentially anti-inflammatory activity may curtail deleterious inflammation.

Acute-Phase Proteins↗
PubMed1996

Interaction of the macrolide azithromycin with phospholipids. II. Biophysical and computer-aided conformational studies.

In a comparison paper, we show the azithromycin causes a lysosomal phospholipidosis in cultured cells, binds in vitro to negatively charged bilayers without causing aggregation or fusion, and inhibits lysosomal phospholipase A1. In this paper, we show that azithromycin decreases the mobility of the phospholipids in negatively charged liposomes (using 31P nuclear magnetic resonance) and that it increases the fluidity of the acyl chains close to the hydrophilic/hydrophobic interface, but not deeper into the hydrophobic domain (assessed by measuring the fluorescence polarization of trimethylammonium-diphenylhexatriene and diphenyhexatriene, respectively). Computer-aided conformational analysis of mixed monolayers of azithromycin and phosphatidylinositol shows that the drug can be positioned largely in the hydrophobic domain, but close to the interface, with the macrocycle facing the C1 of the fatty acids (allowing the N9a endocyclic tertiary amine to interact with the phospho-groups), the cladinose located on the hydrophobic side of the lipid/water interface and the desosamine projected into the hydrophobic domain. This position is consistent with the experimental data. Analysis of virtual molecules shows that this unanticipated behavior to the shielding of the ionizable N3' amino-group in the desosamine by methyl-groups, and to the wide dispersion of hydrophobic domains all over the molecule. The interaction of azithromycin with phospholipids may account for some of its unusual pharmacokinetic properties and for its potential to cause lysosomal phospholipidosis.

Anti-Bacterial Agents↗
PubMed1996

Azithromycin therapy for Cryptosporidium parvum infection in four children infected with human immunodeficiency virus.

Cryptosporidium parvum intestinal infection in immunodeficient patients can cause severe intestinal fluid losses with severe dehydration or chronic diarrhea with malnutrition. Therapies tried in human beings and animals include paromomycin, clarithromycin, azithromycin, octreotide, hyperimmune bovine colostrum, and bovine transfer factor. No specific therapy has been found to be consistently beneficial to children. We report azithromycin treatment of four children with acquired immunodeficiency syndrome who had severe diarrheal illnesses in which Cryptosporidium parvum was the sole pathogen detected. Three of these children had a marked decrease in stool volume and frequency within 36 hours of initiating therapy and resolution of diarrhea within 5 days; Cryptosporidium organisms became undetectable on examination of stool or colonic biopsy or by both after therapy was discontinued. A fourth patient required prolonged therapy with azithromycin to achieve clearance. Azithromycin therapy should be considered for immunocompromised patients with intestinal Cryptosporidium infection.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Height as a proxy for weight in determining azithromycin treatment for paediatric trachoma.

Azithromycin (Zithromax, Pfizer Inc., New York, NY, USA) is effective in the control of blinding trachoma. Community-based azithromycin treatment is recommended by the World Health Organization as part of a multipronged strategy aimed at the global elimination of binding trachoma by the year 2020. Paediatric trachoma is treated with azithromycin according to weight at a target dosage of 20 mg/kg. However, conventional weight-based treatment may be problematic in the field due to the logistical difficulties associated with weight scales. We assessed the accuracy of using height as a proxy for weight to determine azithromycin treatment in 4 countries--Viet Nam, Tanzania, Ghana, and Mali--where mass treatment programmes are underway. Population-based data collected from 1988 to 2000 were analysed using least squares regression. Height treatment schedules were developed for each data set. The accuracy of each schedule was evaluated according to the percentage of children receiving treatment within a dosage range of 20-30 mg/kg, a conservative estimate of the safe and effective treatment range for paediatric trachoma. Using height to determine dose, 89-95% of children would receive a dosage of 20-30 mg/kg. In these populations, height-based treatment is a reliable alternative to conventional weight-based treatment. Methods for developing height schedules presented in this analysis could be applied to other regions and therapeutics.

Administration, Oral↗
PubMed2003

Delirium in the elderly resulting from azithromycin therapy.

BACKGROUND: Azithromycin, a semi-synthetic azalide antibiotic, is a macrolide that thus far has not shared the neuropsychiatric side effects of other macrolides such as erythromycin and clarithromycin. METHODS: We now report significant delirium associated with conventional dosing of azithromycin in two geriatric patients who were being treated for lower respiratory tract infection. RESULTS: The onset of delirium was apparent within 72 hours of initiating azithromycin therapy and lasted 48 to 72 hours after discontinuing treatment with the drug. CONCLUSIONS: In contrast to the adverse central nervous system symptoms associated with clarithromycin, those induced by azithromycin seem to take longer to resolve, perhaps based upon the longer elimination half-life of the latter antimicrobial, particularly in geriatric women.

Aged↗