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PubMed1998

Azithromycin versus placebo in acute infectious rhinitis with clinical symptoms but without radiological signs of maxillary sinusitis.

In this double-blind, parallel-group, multicenter study, 169 patients with symptoms of maxillary sinusitis but without radiographically confirmed empyema (pus) were randomly assigned to receive either 500 mg azithromycin once daily for 3 days (87 patients) or placebo daily for 3 days (82 patients). Nasal secretion, maxillary tenderness and pain, nasal obstruction, general malaise, and hyposmia were assessed at the start of the study and on days 4, 11, and 25 of treatment. After 11 days 58% of the patients in the azithromycin group were cured versus 31% in the placebo group; after 25 days the cure rate was 79% versus 67%, respectively. When both cure and improvement were considered, the corresponding figures after day 25 were 90% and 88%, respectively. Adverse events, predominantly gastrointestinal, occurred in 24 (27%) of the azithromycin-treated patients and in 15 (18%) of those treated with placebo, but the difference was not statistically significant. There was a difference in efficacy in favor of azithromycin in the treatment of rhinitis with symptoms of maxillary sinusitis but without radiological signs of empyema (pus). Antibiotics should only be used to alleviate symptoms in patients with moderate to severe symptoms, as the results after 25 days for both improvement and cure are equal. In the treatment of acute rhinitis with symptoms and signs of maxillary sinusitis but without empyema, treatment with azithromycin seems to result in a better cure rate after 10-12 days when compared with placebo.

Adolescent↗
PubMed1991

In vivo activity of the macrolide antibiotics azithromycin, roxithromycin and spiramycin against Toxoplasma gondii.

The macrolide antibiotics azithromycin, roxithromycin and spiramycin were examined in parallel for in vivo activity against Toxoplasma gondii. Azithromycin was considerably more active in protecting mice against death due to acute toxoplasmosis even when the other two antibiotics were used at twice its dose. The higher activity of azithromycin prompted a further examination of its activity against five different strains of Toxoplasma gondii, including two isolated from patients with AIDS. Although variable degrees of protection against death were noted, treatment with 200 mg/kg/day for ten days was sufficient to promote survival of 100% of mice infected with inocula as high as 1 x 10(5) tachyzoites of Toxoplasma gondii. 90% of mice inoculated with 1 x 10(5) tachyzoites of strain MO, isolated from an AIDS patient, and treated orally with 200 mg/kg/day for ten days survived the infection whereas only 40% of mice infected with the same inoculum of the SOU strain, also isolated from an AIDS patient, survived. Tissue concentrations of azithromycin were examined in treated infected and non-infected mice. In both groups of mice azithromycin attained high concentrations in liver, spleen and heart, which exceeded concurrent serum levels by 25- to 200-fold. The concentrations in the brain were almost tenfold higher than the concentrations in serum after treatment with 200 mg/kg/day for ten days. Moreover, the concentrations in brains of infected mice were approximately two-fold higher than in brains of non-infected mice.

Animals↗
PubMed1988

Comparative studies on the effects of erythromycin A and azithromycin upon extracellular release of lysosomal enzymes in inflammatory processes.

In the present studies the in vivo and in vitro effects of erythromycin A and azithromycin, a new type of macrolide (Fig. 2.), were investigated upon extracellular release of lysosomal enzymes, beta-glucuronidase (beta-Gluc) and beta-N-acetylglucosaminidase (beta-Glm) by using two experimental model systems: in vivo-adjuvant-induced arthritis in rats and in vitro- human polymorphonuclear leucocytes (PMNL) exposed to bovine serum albumin/anti-bovine serum albumin (BSA/anti-BSA), immune complex. Administrations of erythromycin A or azithromycin at doses of 5, 10 and 15 mg/kg into rats one day prior and 2, 4, 6, 8 and 10 days after a single subplantar injection of Freund's complete adjuvant significantly (p less than 0.01) inhibited extracellular release of lysosomal enzymes tested in the synovial fluid of injected left hind paw. These effects were dose-dependent. Further, erythromycin A and azithromycin at concentrations of 10(-7) M, 10(-6) M and 10(-5) M significantly (p less than 0.01) reduced excocytosis of both lysosomal enzymes, beta-Gluc and beta-Glm from human PMNL initiated by BSA/anti-BSA in a dose-related fashion. However, azithromycin was by far more effective (p less than 0.01) in decreasing extracellular release of beta-Gluc and beta-Glm either in the in vivo or in vitro experiments in comparison with erythromycin A. Appropriate control experiments excluded the possibilities that erythromycin A or azithromycin interfered with activities of lysosomal enzymes or with test reagents. Also, in no instances was there enhanced release of a cytoplasmic enzyme LDH.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylglucosaminidase↗
PubMed1991

Spectrum of activity of azithromycin.

In recent years, a number of newer macrolides have been developed. One such antibiotic is azithromycin, which has a 15-membered ring structure and is classed as an azalide. The limitations of erythromycin and the discovery of pathogenic bacteria such as Campylobacter, Legionella and Chlamydia species provide incentives to study the usefulness of newer antibiotics of this class. Azithromycin has good activity against staphylococci, streptococci, Moraxella catarrhalis and other rapidly growing pyogenic bacteria. The good activity of azithromycin against Haemophilus influenzae (MIC90 0.5 mg/l) is particularly important as erythromycin has only marginal activity against this organism. Azithromycin has also been shown to be more potent than the macrolides against Enterobacteriaceae. In common with erythromycin and tetracycline, the agent has good activity against Legionella, Chlamydia and Campylobacter. Opportunistic infections involving Toxoplasma gondii and Pneumocystis carinii are an increasing problem and azithromycin is particularly interesting in view of its activity against these difficult-to-treat organisms.

Animals↗
PubMed1991

Phagocyte uptake and transport of azithromycin.

Azithromycin achieves high concentrations in phagocytic cells and in fibroblasts. The newer macrolides also have this property but the intracellular penetration of azithromycin in relation to extracellular concentration is particularly notable. As a weak base, azithromycin is thought to concentrate in lysosomes of phagocytes and fibroblasts but many in vitro factors such as pH and temperature also affect the uptake process. Uptake of azithromycin by polymorphonuclear leucocytes results in an intracellular/extracellular concentration ratio of approximately 40 after one hour of incubation. Intraphagocytic antimicrobial activity has been demonstrated but is rather less than might be anticipated from the intracellular concentrations that are reached. Importantly, the high antibiotic levels found intracellularly do not appear to disrupt normal phagocyte function. Although azithromycin levels in the blood are low soon after administration, tissue concentrations are high and sustained. It appears that fibroblasts serve as a reservoir of drug in tissue, allowing activity against organisms and possibly transferring antibiotic to phagocytic cells for activity against intracellular pathogens and delivery to infection sites.

Azithromycin↗
PubMed1991

High and prolonged pulmonary tissue concentrations of azithromycin following a single oral dose.

Antibiotic concentrations in pulmonary tissue samples and plasma were studied in this open investigation. Twenty-nine patients scheduled for elective pulmonary surgery received a single oral dose of 500 mg azithromycin 24, 72, 96 or 120 h prior to the operation; two patients received 250 mg b.i.d. Blood samples were taken before and at the time of resection, and tissue was obtained during surgery. Plasma and tissue concentrations of azithromycin were measured by high performance liquid chromatography (HPLC) and a microbiological bioassay. Only one patient had a detectable plasma concentration of azithromycin (0.13 micrograms/ml), measured 24 h post-dose by HPLC. However, high and sustained levels were found in lung tissue: mean concentrations measured by HPLC were 3.10 micrograms/g (SD +/- 2.17), 2.55 micrograms/g (SD +/- 1.36), 3.94 micrograms/g (SD +/- 2.40) and 3.13 micrograms/g (SD +/- 0.50) at 24, 72, 96 and 120 h, respectively. Bioassay results were similar to those for the HPLC assay. In summary, azithromycin levels in pulmonary tissue remained close to 3 micrograms/g for up to 5 days after a single oral 500 mg dose, in contrast to plasma levels which were much lower. The lung concentrations found are inhibitory for many sensitive respiratory pathogens and short-course azithromycin therapy is therefore a possibility.

Administration, Oral↗
PubMed1992

In vitro activity of azithromycin and tetracycline against 358 clinical isolates of Brucella melitensis.

The in vitro activity of azithromycin against human pathogenic strains of Brucella melitensis was tested at three centres and compared to that of tetracycline, the standard antibiotic currently used for the treatment of human brucellosis. MIC determination was carried out. Tested concentration ranges for both azithromycin and tetracycline were between 0.03 and 16 micrograms/ml. Brucella melitensis biotype 1, strain M16 was employed as a control microorganism. A total of 358 Brucella melitensis strains from human blood cultures were tested. MIC90 (micrograms/ml) values ranged from 0.5 to 1.00 for azithromycin and were 0.25 for tetracycline. It was concluded that there was little difference in the sensitivity of pathogenic Brucella melitensis to azithromycin and tetracycline isolated from three different regions in Spain. These results encourage further investigations on the possible therapeutic role of azithromycin in brucellosis.

Azithromycin↗
PubMed2002

Inhibition of 50S ribosomal subunit assembly in Haemophilus influenzae cells by azithromycin and erythromycin.

Azithromycin is an important antibiotic for the treatment of several different Gram-positive and Gram-negative bacterial infections. Erythromycin and clarithromycin are less useful antibiotics against Gram-negative infections. This difference in inhibitory activity was explored by comparing the effects of azithromycin and erythromycin on cellular functions in Haemophilus influenzae cells. Effects of both antibiotics on translation, cell viability, and growth rates have been measured. An IC(50) of 0.4 microg/ml was found for the effects of azithromycin on each of these processes. For erythromycin, an IC(50) of 1.5 microg/ml was observed, indicating a fourfold lower sensitivity of the organisms to this compound. The features of a second target for macrolide antibiotic inhibition in H. influenzae cells have also been examined. Inhibition of the synthesis of the large 50S ribosomal subunit was measured. Subunit formation was prevented in a concentration dependent fashion, with azithromycin showing a ninefold greater effect on this process compared with erythromycin. Synthesis of the 30S ribosomal subunit was not effected. Pulse and chase labeling kinetics confirmed the slower synthesis rate of the 50S particle in the presence of each antibiotic. The results are discussed in terms of the stronger effect of azithromycin on ribosome biosynthesis in this organism.

Anti-Bacterial Agents↗
PubMed2006

Efficacy and safety of intravenous moxifloxacin versus cefoperazone with azithromycin in the treatment of community acquired pneumonia.

To compare the efficacy, safety, and tolerability of intravenous moxifloxacin with those of a commonly used empirical antibiotic regimen, cefoperazone and azithromycin in the treatment of community acquired pneumonia (CAP) in adult patients requiring initial parenteral therapy, 40 patients with CAP were divided into two groups, a moxifloxacin group (n = 20) and a control group (n = 20), which were treated for 7 to 14 days. The patients in the moxifloxacin group were intravenously given 400 mg of moxifloxacin (Avelox) once a day. Patients in the control group were administered 2.0 g of cefoperazone twice a day and azithromycin 0.5 g once a day. Clinical, bacteriological, and laboratory examinations were performed before the treatment, and at the end of the treatment. Our results showed that there was no significant difference in the clinical efficacy rate between two treatment groups at end of therapy (90% for moxifloxacin, 95% for cefoperazone plus azithromycin) (P > 0.05). The bacteriologic eradication rate at the end of treatment was 90% in the moxifloxacin group and 80% in the cefoperazone-plus-azithromycin group, whereas there was no significant difference between the two groups (P > 0.05). In addition, both drugs were well-tolerated in this trial, with the number of drug-related adverse events being comparable. It is concluded that moxifloxacin is an effective and well-tolerated treatment for CAP and was equivalent to the commonly used empirical treatment of cefoperazone plus azithromycin. Moxifloxacin is likely to offer clinicians an alternative for reliable empirical CAP treatment in the face of increasing antibiotic resistance.

Adolescent↗
PubMedDate not supplied

Comparison of azithromycin and doxycycline in the treatment of erythema migrans.

BACKGROUND: A randomized, multicenter, open clinical trial was undertaken in order to compare the efficacies of azithromycin and doxycycline in the treatment of patients with Lyme disease associated with erythema migrans. PATIENTS AND METHODS: A total of 48 patients was treated orally with azithromycin, 500 mg bid on the 1st day, followed by 500 mg once daily for the next 4 days or doxycycline (40 patients) 100 mg bid for 14 days. RESULTS: Intention-to-treat analysis of clinical efficacy showed no difference between the two treatment regimens. Clinical success was observed in 46 (95.8%) azithromycin- and 33 (82.5%) doxycycline-treated patients, (p = 0.0731). Minor symptoms persisted or appeared in the posttreatment period in two of 47 azithromycin- and three of 35 doxycycline-treated patients (p = 0.646). Major manifestations appeared only in two patients in the doxycycline group (p = 0.179). There was no difference in the tolerability of both drugs. CONCLUSION: Azithromycin (a total dose of 3 g) is equally effective as standard doxycycline treatment for erythema migrans in adult patients.

Administration, Oral↗
PubMed1991

Azithromycin and amoxicillin in the treatment of acute maxillary sinusitis.

Seventy-eight patients participated in this multicenter, third-party-blinded study comparing a single daily dose of azithromycin for 5 days (500 mg on day 1 followed by 250 mg/day for days 2-5) with amoxicillin (500 mg three times daily) for 10 days in the treatment of acute bacterial maxillary sinusitis. A total of 38 evaluable patients contributed to the efficacy analysis. The overall clinical response rate was 100% for both antibiotics. The clinical cure rate, as determined by the investigator, was 73.9% for azithromycin and 73.3% for amoxicillin; improvement was seen in 26.1% and 26.7% of patients, respectively. The bacteriologic cure rate in these 38 patients was 100% in both groups. Both antibiotics were well tolerated; side effects were reported by 4.9% of patients in the azithromycin group compared with 8.1% in the amoxicillin group. Most of these side effects were gastrointestinal disturbances that were reported by four of five (three amoxicillin, one azithromycin) patients experiencing side effects. All side effects were mild, and in both groups only minor abnormalities in laboratory data were detected. No patient discontinued the study because of treatment-related side effects. In this study, a 5-day course (one dose per day) of azithromycin proved to have efficacy, safety, and tolerability that was equal to a 10-day course (three doses per day) of amoxicillin in the treatment of acute bacterial sinusitis.

Acute Disease↗
PubMed1991

Clinical toleration and safety of azithromycin.

The toleration and safety profile of the azalide antibiotic, azithromycin, has been assessed in 3,995 patients aged 2-94 (mean, 36) years, comprising 1,644 females and 2,351 males. Patients with infections of the respiratory tract or skin/skin structure received 1.5 g azithromycin over 5 days; patients with urethritis/cervicitis caused by Chlamydia were treated with 1 g as a single dose. Assessments of side effects and laboratory safety test abnormalities were made pretreatment and approximately 7-14 and 30 days after the start of therapy. Twelve standard antibiotics have been used for comparison. Overall, side effects were recorded in 12.0% of patients, significantly less (p less than 0.05) than with comparative drugs (14.2%). The most common side effects were diarrhea (3.6%), abdominal pain (2.5%), and other gastrointestinal symptoms. Ninety-three percent of side effects were classed as mild or moderate, and only 0.7% of patients withdrew from treatment, significantly less (p less than 0.001) than with comparative agents (2.6%). The frequency of side effects was not affected by patient age. Azithromycin had no marked or consistent effect on laboratory safety parameters. Treatment-related laboratory abnormalities were rare, the most common being transient increases of ALT and AST in 1.7% and 1.5% of patients, respectively. Specific tests revealed no neurologic, audiometric, or ophthalmologic abnormalities, or evidence of phospholipidosis. There were no pharmacokinetic interactions observed with theophylline, warfarin, cimetidine, carbamazepine, or methylprednisolone, but coadministration with food altered the absorption of the drug. Coadministration with antacids decreased the peak serum concentration of azithromycin, but did not affect its overall absorption. Azithromycin was well tolerated in the presence of a wide variety of concurrent illnesses and medications.

Adolescent↗
PubMed1995

Azithromycin and terfenadine: lack of drug interaction.

A double-blind placebo-controlled study was conducted in healthy men to determine the effect of coadministration of azithromycin on the pharmacodynamics and pharmacokinetics of terfenadine. Administration of 500 mg azithromycin for 1 day and 250 mg on 4 subsequent days did not affect the pharmacokinetics of the pharmacologically active terfenadine carboxylate metabolite when 60 mg terfenadine was given twice daily for 12 days, starting 7 days before azithromycin administration. Terfenadine alone resulted in a 0.010 msec increase in the rate-corrected QT interval (QTc), but the incremental effects of azithromycin and placebo on QTc in volunteers receiving terfenadine were not statistically different. It is concluded that the potentially life-threatening disorders that have been attributed to a pharmacokinetic interaction between macrolide antibiotics and terfenadine are unlikely to take place in patients treated simultaneously with azithromycin and terfenadine.

Adult↗
PubMed2005

Antibiotic prophylaxis with azithromycin or penicillin for childhood-onset neuropsychiatric disorders.

BACKGROUND: The acronym PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections) describes a subgroup of children with obsessive-compulsive disorder and/or tic disorder that experience symptom exacerbations following streptococcal infections. We hypothesized that the prevention of streptococcal infections among children in the PANDAS subgroup would decrease neuropsychiatric symptom exacerbations. METHODS: Twenty-three subjects with PANDAS were enrolled in a double blind, randomized controlled trial. Antibiotic prophylaxis with penicillin or azithromycin was administered for 12 months. Rates of streptococcal infections and neuropsychiatric symptom exacerbations were compared between the study year and the baseline year prior to entry. RESULTS: Significant decreases in streptococcal infections during the study year were found with a mean of .1 (.3 SD) per subject, compared to the baseline year with 1.9 (1.2 SD) in the penicillin group and 2.4 (1.1 SD) in the azithromycin group [p<.01]. Significant decreases in neuropsychiatric exacerbations during the study year were also found with a mean of .5 (.5 SD) per subject in the penicillin group and .8 (.6 SD) in the azithromycin group, compared to the baseline year with 2.0 (.9 SD) in the penicillin group and 1.8 (.6 SD) in the azithromycin group [p<.01]. CONCLUSIONS: Penicillin and azithromycin prophylaxis were found to be effective in decreasing streptococcal infections and neuropsychiatric symptom exacerbations among children in the PANDAS subgroup.

Antibiotic Prophylaxis↗
PubMed2004

Azithromycin reverses anticancer drug resistance and modifies hepatobiliary excretion of doxorubicin in rats.

The present study aims to investigate whether azithromycin reverses P-glycoprotein-dependent anticancer drug resistance in vitro and modifies the hepatobiliary excretion of doxorubicin, a substrate for P-glycoprotein in vivo. Azithromycin increased dose-dependently the intracellular accumulation of doxorubicin in adriamycin-resistant human myelogenous leukemia cells (K562/ADR) with no effect on the expression of P-glycoprotein in the cells. However, the inhibitory effect was much weaker than that of cyclosporin A and was comparable to that of erythromycin. When Sprague-Dawley (SD) rats, which have drug transporting P-glycoprotein and multidrug resistance-associated protein 2 (Mrp2) in the bile canalicular membrane of hepatocytes, received an infusion of doxorubicin, the steady-state biliary clearance of doxorubicin was significantly decreased for 40 min after a single intravenous injection of azithromycin. However, azithromycin did not increase the plasma concentration of doxorubicin. The biliary clearance of doxorubicin in Eisai hyperbilirubinemic rats (EHBRs), which have a hereditary deficiency in Mrp2, was significantly decreased compared with that in Sprague-Dawley rats, suggesting the involvement of Mrp2 in the biliary excretion of doxorubicin. The present findings suggest that azithromycin overcomes P-glycoprotein-dependent anticancer drug resistance of tumors by inhibiting the binding of doxorubicin to P-glycoprotein in K562/ADR cells and inhibits the hepatobiliary excretion of drugs that are substrates for P-glycoprotein and Mrp2.

Animals↗
PubMed2005

Modulation of neutrophil and inflammation markers in chronic obstructive pulmonary disease by short-term azithromycin treatment.

The anti-inflammatory potential of azithromycin in chronic obstructive pulmonary disease (COPD) patients was explored following a standard oral dosing regimen. Patients with moderate and severe COPD were treated with azithromycin (500 mg, n=16) or placebo (n=8) once daily for 3 days in a randomized, double blind design, to compare effects on inflammation markers with those seen in a previous study in healthy volunteers. A battery of tests was made on serum, blood neutrophils and sputum on days 1 (baseline), 3, 4, 11, 18 and 32. In comparison to placebo, azithromycin resulted in an early transient increase in serum nitrites plus nitrates (day 3), associated with a tendency towards an increase in the blood neutrophil oxidative burst to phorbol myristic acetate. Subsequently, prolonged decreases in blood leukocyte and platelet counts, serum acute phase protein (including C reactive protein) and soluble E-selectin and blood neutrophil lactoferrin concentrations and a transient decrease in serum interleukin-8 were observed. Blood neutrophil glutathione peroxidase activity showed a prolonged increase after azithromycin treatment. The biphasic facilitatory-then-inhibitory response to azithromycin seen in healthy volunteers is not so clearly detectable in COPD patients, only potential anti-inflammatory effects. Treatment for longer periods may give therapeutic anti-inflammatory benefit in these patients.

Adult↗
PubMed2006

Anti-inflammatory activity of azithromycin attenuates the effects of lipopolysaccharide administration in mice.

Macrolide antibacterials inhibit the production of various cytokines and the migration of inflammatory cells. These anti-inflammatory actions of macrolides may be beneficial in attenuating inflammatory processes involved in bacterial sepsis. Therefore, we investigated the ability of azithromycin to attenuate the deleterious effects of lipopolysaccharide (LPS), in three different LPS-induced inflammatory models. Our results show that azithromycin (10 and 100 mg/kg) significantly attenuated the intraperitoneal LPS-induced increase in plasma TNF-alpha concentration. It also increased survival rate in a septic shock model in mice challenged with intravenous LPS. Oral treatment with azithromycin (up to 300 mg/kg) was less effective in suppressing neutrophil infiltration into the lungs 24 h after intranasal LPS challenge, possibly because of a slower onset of action or inadequate dosing. In the same model, azithromycin given intraperitoneally significantly improved inflammatory markers (total cell number, neutrophil percentage and MIP-2 concentration) in bronchoalveolar lavage fluid. In conclusion, azithromycin exhibits significant anti-inflammatory properties but the potency of such effects varies depending on the experimental model and route of administration.

Administration, Oral↗
PubMed2005

Efficacy and safety of a novel, single-dose azithromycin microsphere formulation versus 10 days of levofloxacin for the treatment of acute bacterial sinusitis in adults.

OBJECTIVE: To compare the efficacy and safety of a single 2.0-g dose of a novel azithromycin microsphere formulation with that of 10 days of levofloxacin, 500 mg/d, when used to treat adults with uncomplicated acute bacterial maxillary sinusitis (ABS). STUDY DESIGN AND SETTING: An international, multicenter, randomized, double-blind, double-dummy trial. Eligible outpatients > or =18 years of age with clinical and radiographic evidence of ABS underwent maxillary sinus aspiration before randomization. Primary endpoint was clinical efficacy at the test-of-cure visit (day 17-24). RESULTS: Clinical success rates were 94.5% (242/256) in azithromycin-microspheres-treated patients and 92.8% (233/251) in the levofloxacin group. In patients with documented Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis, clinical cure rates were 97.3% (36/37), 96.3% (26/27), and 100% (8/8), respectively, for the azithromycin group and 92.3% (36/39), 100% (30/30), and 90.9% (10/11), respectively, for the levofloxacin group. CONCLUSIONS: Single-dose azithromycin microspheres provided clinical and bacteriologic efficacy and safety comparable to 10 days of levofloxacin. SIGNIFICANCE: A novel microsphere formulation of azithromycin given as a single dose was safe and effective for the treatment of ABS.

Acute Disease↗