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PubMedDate not supplied

Pharmacokinetics of azithromycin in normal and impaired renal function.

Plasma and urine levels of 12 healthy subjects and 30 patients with renal insufficiency of different degrees were examined after oral administration of four 250 mg capsules azithromycin (total daily dose 1,000 mg). The concentrations were determined by cup plate method. The pharmacokinetic parameters were determined model-dependent and noncompartmentally. Neither the area under the plasma concentration curve nor the distribution volume in steady state (16 l/kg body weight) nor the maximal plasma concentration were significantly affected by renal insufficiency. Thus the dosage regimen of azithromycin in renal impairment may (and should) be the same as in patients with normal renal function. The nonrenal clearance is not affected by renal insufficiency, but the concentration of the substance in the tubular lumen (the "tubular load") may be increased.

Administration, Oral↗
PubMed1992

Inhibition of motility of Pseudomonas aeruginosa and Proteus mirabilis by subinhibitory concentrations of azithromycin.

Exposure to subinhibitory concentrations (4-8 micrograms/ml) of azithromycin resulted in loss of motility in Proteus mirabilis strains and a significant reduction of motility in Pseudomonas aeruginosa strains. Examination revealed that the loss of motility was due to a total absence of flagella in Proteus mirabilis while the poor motility observed in Pseudomonas aeruginosa was due to absence of flagella in the majority of the population. Since motility may be considered a pathogenicity trait in the two species, these results confirm the unusual ability of azithromycin to reduce the expression of virulence factors in gram-negative pathogens.

Azithromycin↗
PubMed1990

Comparative in vitro activity of azithromycin, clarithromycin, erythromycin and lomefloxacin against Mycoplasma pneumoniae, Mycoplasma hominis and Ureaplasma urealyticum.

The in vitro activity of three macrolides, azithromycin, clarithromycin and erythromycin and a new fluoroquinolone, lomefloxacin, against pathogenic mycoplasma (16 to 18 strains of Mycoplasma pneumoniae, 41 to 77 strains of Mycoplasma hominis, 65 to 104 strains of Ureaplasma urealyticum) was compared. The three macrolides were highly active against Mycoplasma pneumoniae. Clarithromycin was the most active macrolide against Ureaplasma urealyticum whereas azithromycin was somewhat more active than erythromycin against Mycoplasma hominis. Lomefloxacin was moderately active against all three mycoplasma species.

4-Quinolones↗
PubMed1991

An open study to compare the pharmacokinetics, safety and tolerability of a multiple-dose regimen of azithromycin in young and elderly volunteers.

An open, parallel study was conducted to compare the pharmacokinetics of oral azithromycin in young and elderly healthy volunteers. A total of 12 young subjects (six males, six females) with a mean age of 29 (range 22-39) years and another 12 elderly subjects (six males, six females) with a mean age of 72 (range 67-80) years were given a standard five-day therapeutic regimen of azithromycin (500 mg single dose on day 1 and 250 mg once daily on days 2-5). Pharmacokinetic results indicated that Cmax, Cmin and urinary excretion were similar in the two age groups. Mean AUC0-24 was significantly greater (2.7 micrograms.h/ml) at day 5 in the elderly subjects compared with the younger age group (AUC0-24 = 2.1 micrograms.h/ml) (p = 0.041). Similarly, tmax values on days 1 and 5 were significantly greater in the elderly subjects; 3.8 h compared with 2.5 h in young subjects (p = 0.005) on day 1 and 4.4 h, compared with 3.2 h (p = 0.047) on day 5. There was also evidence of an inverse relationship between creatinine clearance and AUC0-24 (p less than 0.01) but not urinary excretion or Cmax. Despite these observations, it is concluded that the differences between the two age groups were of insufficient magnitude to warrant a dose modification in elderly subjects with only mild renal impairment. Side effects, chiefly headache and gastrointestinal symptoms, were reported by seven subjects in each group. No subject, however, was withdrawn from the study and there were no treatment-related abnormalities in any of the laboratory parameters measured.

Administration, Oral↗
PubMed2001

[Confluent and reticulate papillomatosis. Successful therapy with azithromycin].

Confluent and reticulated papillomatosis is a fairly rare dermatosis of still unknown origin affecting mostly female young adults. The lesions are mainly localized in the midline of the trunk. Systemic treatment is the treatment of choice because the disease is resistant to topical therapy and recurrences are often seen. In recent publications retinoids and minocycline have been reported as the favourite therapeutic approaches. We successfully treated a 19-year-old-girl with azithromycin resulting in a complete healing of all skin lesions. The patient has been free of disease for five months. Based on our own case and data in literature, azithromycin is an effective, reasonable and safe therapeutic alternative.

Administration, Oral↗
PubMed2005

Accumulation and turnover of 23S ribosomal RNA in azithromycin-inhibited ribonuclease mutant strains of Escherichia coli.

Ribosomal RNA is normally a stable molecule in bacterial cells with negligible turnover. Antibiotics which impair ribosomal subunit assembly promote the accumulation of subunit intermediates in cells which are then degraded by ribonucleases. It is predicted that cells expressing one or more mutated ribonucleases will degrade the antibiotic-bound particle less efficiently, resulting in increased sensitivity to the antibiotic. To test this, eight ribonuclease-deficient strains of Escherichia coli were grown in the presence or absence of azithromycin. Cell viability and protein synthesis rates were decreased in these strains compared with wild type cells. Degradation of 23S rRNA and recovery from azithromycin inhibition were examined by 3H-uridine labeling and by hybridization with a 23S rRNA specific probe. Mutants defective in ribonuclease II and polynucleotide phosphorylase demonstrated hypersensitivity to the antibiotic and showed a greater extent of 23S rRNA accumulation and a slower recovery rate. The results suggest that these two ribonucleases are important in 23S rRNA turnover in antibiotic-inhibited E. coli cells.

Azithromycin↗
PubMed1998

Azithromycin and clarithromycin inhibition of 50S ribosomal subunit formation in Staphylococcus aureus cells.

The ID50 values for azithromycin and clarithromycin inhibition of translation and of 50S assembly in Staphylococcus aureus cells have been measured. For clarithromycin, 50% inhibition of growth occurred at 0.075 microg/ml, and the effects on translation and 50S formation were equivalent at 0.15 microg/ml. The inhibition of these processes by azithromycin was less effective, with an ID50 of 2.5 microg/ml for growth and 5 microg/ml for inhibition of translation and 50S formation. The additive effects of each of these drugs on translation and 50S formation account quantitatively for their observed influence on cellular growth rates. In macrolide-treated cells, there was also a direct relationship between the loss of ribosomal RNA from the 50S subunit and its accumulation as oligoribonucleotides. These results are compared with the previously described effects of erythromycin on these same processes.

Anti-Bacterial Agents↗
PubMed1999

Efficacy of treatment with paromomycin, azithromycin, and nitazoxanide in a patient with disseminated cryptosporidiosis.

A 24-year-old HIV-positive heterosexual woman with disseminated cryptosporidiosis was monitored from January 1998 to May 1999. During this period, consecutive stool, sputum, and bile examinations showed the constant presence of Cryptosporidium oocysts. Although the patient was repeatedly treated with oral paromomycin and azithromycin and, finally, nitazoxanide, her condition continued to deteriorate. In order to monitor the in vitro susceptibility of the parasite, specimens from various sites were collected periodically. When the first clinical isolate was tested, the antimicrobial agents used (azithromycin at a concentration of 8 mg/l, paromomycin at of 1 mg/ml, and nitazoxanide at 10 mg/l) produced a decrease in parasite counts of 26.5%, 63.4%, and 67.2%, respectively. Subsequent isolates of Cryptosporidium parvum showed similar susceptibilities. This case demonstrates that failure of clinical treatment corresponded to inadequate growth inhibition of the parasite in vitro.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Sensitivity in vitro of Giardia intestinalis to dyadic combinations of azithromycin, doxycycline, mefloquine, tinidazole and furazolidone.

The new macrolide antibiotic, azithromycin, produced significant growth inhibition of Giardia intestinalis at 100 micrograms/ml, but adherence inhibition was significant at concentrations as low as 1 microgram/ml for the two strains used in these experiments. The dyadic combinations of azithromycin-furazolidone, doxycycline-mefloquine, doxycycline-tinidazole and mefloquine-tinidazole were synergistic for inhibition of adherence. These results suggest that these dyadic combinations may be worthy of consideration for chemotherapy of recalcitrant giardiasis.

Animals↗
PubMed1991

High-performance liquid chromatographic assay with electrochemical detection for azithromycin in serum and tissues.

High-performance liquid chromatographic methods using reversed-phase chromatography and electrochemical detection have been developed for the quantitation of azithromycin in serum and tissues of laboratory animals and humans. Serum sample preparation involved addition of internal standard, alkalinization, and solvent extraction. Tissue sample preparation involved Polytron homogenization in acetonitrile containing internal standard, evaporation of the supernatant, alkalinization of the residue, and solvent extraction. Serum samples were chromatographed on an alkylphenyl-bonded silica column eluted with pH 6.8-7.2 mobile phase with a dual-electrode coulometric detector operated in the oxidative screen mode. Serum and tissue samples were chromatographed on a gamma RP-1 alumina column with pH 11 mobile phase with a glassy carbon amperometric detector. Recovery of azithromycin was 87% from serum and 85% from tissues. Linear standard curves were prepared in serum over two concentration ranges (0.01-0.20 and 0.20-2.0 micrograms/ml) and in tissues over several concentration ranges (0.1-2, 1-10, 10-100, and 100-1000 micrograms/g). In serum and tissues, intra- and inter-assay precision ranged from 1 to 8% and 4 to 11%, respectively. The tissue assay has been applied to liver, kidney, lung, spleen, muscle, fat, brain, tonsil, lymph nodes, eye, prostate and other urological tissues, and gynecological tissues.

Azithromycin↗
PubMed1992

Equivalence of a high-performance liquid chromatographic assay and a bioassay of azithromycin in human serum samples.

Two sensitive methods for the determination of the azalide antibiotic azithromycin in human serum were compared. High-performance liquid chromatography (HPLC) and a microbiological assay were simultaneously applied to 768 serum samples obtained in a clinical study. There was excellent agreement between the azithromycin concentrations measured by HPLC and by the bioassay. The correlation coefficient for the two methods was r2 = 0.96. The precision and the sensitivity of the methods were found to be very similar.

Azithromycin↗
PubMed2005

A pooled analysis of seven randomized crossover studies of the palatability of cefdinir oral suspension versus amoxicillin/clavulanate potassium, cefprozil, azithromycin, and amoxicillin in children aged 4 to 8 years.

OBJECTIVE: This analysis of the results of 7 trials compared the taste and smell acceptability scores of cefdinir oral suspension and 4 other pediatric antibiotic oral suspensions--amoxicillin/clavulanate potassium, cefprozil, azithromycin, or generic amoxicillin--using a visual smile-face scale. METHODS: Data from 7 randomized, single-blind, cross-over trials were pooled and analyzed. In each study, children aged 4 to 8 years were asked to taste and smell 2 different antibiotic suspensions and assign preference using a visual smile-face scale. Ratings were converted to a numeric score ranging from 5 (really good) to 1 (really bad). RESULTS: A total of 1011 healthy subjects were randomly assigned to 1 of 2 treatment-order groups; 965 were evaluable for the taste and smell analyses. Baseline demographics of evaluable subjects were similar among test groups. Approximately even proportions of participants were female or male (50.1 % vs 49.9%), most (84.1%) were white, and slightly more participants were aged 7 or 8 years rather than younger (age 4 years, 16.0%; age 5 years, 17.4%; age 6 years, 18.7%; age 7 years, 23.2%; age 8 years, 24.8%). Of the 965 children who tasted both antibiotic suspensions and determined their preference, 798 (82.7%) rated the taste of cefdinir as really good or good (the highest possible ratings); 712 (73.8%) assigned the same ratings to amoxicillin/clavulanate potassium, cefprozil, azithromycin, or generic amoxicillin (P < or = 0.001). With regard to smell, 671 (69.5%) rated the smell of cefdinir as really good or good; 636 (65.9%) assigned these same ratings to the comparator agents (P = NS). CONCLUSION: In this pooled analysis of data from 7 randomized, single-blind, crossover trials, children between the ages of 4 and 8 years preferred the taste of cefdinir oral suspension to that of other pediatric antibiotic suspensions. Based on smile-face scores, subjects found the smell of cefdinir oral suspension to be at least as good as that of the comparators.

Administration, Oral↗
PubMed2004

Susceptibility testing of Singapore strains of Mycoplasma hominis to tetracycline, gatifloxacin, moxifloxacin, ciprofloxacin, clindamycin, and azithromycin by the Etest method.

The minimal inhibitory concentrations of tetracycline, gatifloxacin, moxifloxacin, ciprofloxacin, clindamycin and azithromycin for 28 Singapore clinical Mycoplasma hominis strains were studied using the Etest method. Different incubation conditions did not affect susceptibility categories, except for tetracycline intermediate-susceptibility strains. Tetracycline-susceptibility was only 35.7%. All strains were susceptible to the fluoroquinolones and clindamycin but resistant to azithromycin.

Anti-Bacterial Agents↗
PubMed2004

In vitro activity of fluoroquinolones, azithromycin and doxycycline against chlamydia trachomatis cultured from men with chronic lower urinary tract symptoms.

INTRODUCTION: Little is known about chlamydia survival in the presence of fluoroquinolones in patients with chronic prostatitis syndrome (CPS). In vitro activities of four fluoroquinolones, azithromycin and doxycycline against C. trachomatis in patients with CPS being not treated with antibiotics earlier were investigated and compared. MATERIAL AND METHODS: Chlamydia survival in 304 patients with CPS being not treated with antibiotics earlier was analysed and compared. Infection by C. trachomatis was determined in the urethra and expressed prostatic secretion by cell culture test. RESULTS: Azithromycin and ofloxacin were found to be the most active antichlamydial agent with ciprofloxacin and doxycycline being least active. CONCLUSION: Ofloxacin can be recommended as the primary drug in the treatment of chlamydia-infected patients with CPS. The decision on the prescription of other fluoroquinolones should be made individually. The investigation of chlamydia survival in the presence of antibiotics in patients with CPS and C. trachomatis prior to treatment is recommended.

Adult↗
PubMed2004

Azithromycin treatment follow-up: antibacterial susceptibility of Chlamydia trachomatis in patients with chronic prostatitis.

The antibacterial susceptibility of Chlamydia trachomatis in 138 patients with chronic prostatitis (CP) and clinical failures after antibacterial treatment with azithromycin (AZI) were investigated. Azithromycin was not found to be top-of-the-line drug in the follow-up treatment, showing only average results in vitro. The investigation of the susceptibility of chlamydia to antibiotics in causes of chronic prostatitis is highly recommended.

Anti-Bacterial Agents↗
PubMed2006

In vitro activity of azithromycin and nine comparator agents against 296 strains of oral anaerobes and 31 strains of Eikenella corrodens.

At this time in the USA there are no antimicrobials with specific indications for oral infections, and many of those currently used have limited efficacy against oral anaerobic strains. We tested the activity of azithromycin against a broad range of anaerobic oral pathogens and, at pH 8, found it to be effective against 98% of strains, including all fusobacteria and beta-lactamase-producing strains of Prevotella spp. All strains of Eikenella corrodens were also susceptible to azithromycin but resistant to erythromycin, clindamycin, metronidazole and cefalexin. Other comparator agents were penicillin, amoxicillin/clavulanic acid, tetracycline, levofloxacin and ciprofloxacin. Minimum inhibitory concentrations obtained on agar adjusted to pH 8 were generally one dilution lower than those obtained on agar at pH 7.

Anti-Bacterial Agents↗
PubMed2007

Human serum activity of telithromycin, azithromycin and amoxicillin/clavulanate against common aerobic and anaerobic respiratory pathogens.

Telithromycin is a new ketolide antimicrobial with a good in vitro activity against both aerobic and anaerobic respiratory pathogens. In this study, we evaluated the antibacterial activity over time of telithromycin (800mg), azithromycin (500mg), and amoxicillin/clavulanate (875/125mg) in serum following single oral doses of these agents to 10 healthy subjects. Inhibitory and bactericidal titers were determined at 2, 6, 12, and 24h after each dose and the median titer was used to determine antibacterial activity. Against two azithromycin-resistant strains of Streptococcus pneumoniae, both telithromycin (MIC=0.25 and 0.5 microg/mL) and amoxicillin/clavulanate exhibited inhibitory and cidal activity for at least 6h. All three antibiotics provided prolonged (>or=12h) inhibitory activity against strains of Hemophilus influenzae (telithromycin MIC=4.0 microg/ml). Both telithromycin and amoxicillin/clavulanate exhibited rapid and prolonged inhibitory activity (>or=12h) against each of the anaerobes studied (Finegoldia [Peptostreptococcus] magna Peptostreptococcus micros, Prevotella bivia, and Prevotella melaninogenica). Moreover, both agents provided bactericidal activity against both Prevotella species. In this ex vivo pharmacodynamic study, we found that telithromycin provided rapid and prolonged antibacterial activity in serum against macrolide-resistant strains of S. pneumoniae, beta-lactamase-positive and -negative strains of H. influenzae, and common respiratory anaerobic pathogens. These findings suggest that telithromycin could have clinical utility in the treatment of community-acquired mixed aerobic-anaerobic respiratory tract infections, including chronic sinusitis and aspiration pneumonia.

Administration, Oral↗