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PubMed1997

Azithromycin. A pharmacoeconomic review of its use as a single-dose regimen in the treatment of uncomplicated urogenital Chlamydia trachomatis infections in women.

In women, Chlamydia trachomatis infection often occurs in the urethra or cervix, with up to 70% of infections associated with few or no symptoms. Inadequate treatment may lead to infection of the upper genital tract and subsequent pelvic inflammatory disease (PID) in 10 to 40% of patients. PID causes an increased relative risk of ectopic pregnancy of 2.5 to 7.9 and PID may also lead to tubal infertility in about 17% of patients. 60% of infants born of mothers with C. trachomatis infection may become infected, leading to conjunctivitis in 23% and pneumonia in 21%. All of these sequelae of C. trachomatis infection may require in- or outpatient treatment. With > 4 million infections estimated to occur each year in the US, C. trachomatis is one of the most common and costly of the sexually transmitted pathogens. Treatment options for uncomplicated C. trachomatis infections in nonpregnant women include single-dose azithromycin 1000 mg or doxycycline 100 mg twice daily for 7 days orally. In clinical trials, the bacteriological cure rate of single dose azithromycin 1000 mg (95 to 100%) was similar to that of oral doxycycline 200 mg/day for 7 days (88 to 100%) in nonpregnant women. Azithromycin was at least as well tolerated as doxycycline and was associated with mainly mild gastrointestinal adverse effects including diarrhoea, nausea and abdominal pain. Pharmacoeconomic analyses have sought to determine if the 2.7- to 12-fold higher acquisition costs of azithromycin in comparison with doxycycline are offset by its simple single-dose regimen which is likely to aid patient compliance and so optimise drug efficacy. All analyses were retrospective cost-effectiveness decision-tree models and mainly considered direct costs. All models incorporated an estimate of noncompliance with doxycycline and its influence on efficacy. For the treatment of confirmed C. trachomatis infection, azithromycin saved around $US1200 per major outcome avoided (1993 values; third-party payer perspective in the US) or US$3502 per case of PID avoided (1993 values; US healthcare system perspective) compared with doxycycline. If infection was treated empirically, azithromycin was more costly than doxycycline by $US792 (1993 values), but the result was sensitive to changes of some parameters of the model. Azithromycin was more costly than doxycycline from the perspective of a public health clinic which paid for the treatment of initial infection and acute sequelae only. Thus, pharmacoeconomic data from the US support the use of azithromycin in the treatment of nonpregnant women with confirmed C. trachomatis urogenital infections from the perspective of the healthcare system or third-party payer; however, from the perspective of a public clinic, doxycycline is the less costly option. Decreases in doxycycline compliance or azithromycin acquisition cost are factors that favour azithromycin.

Anti-Bacterial Agents↗
PubMed2005

The disease-modifying effects of twice-weekly oral azithromycin in patients with bronchiectasis.

INTRODUCTION: Bronchiectasis is a chronic pulmonary process characterized by recurrent respiratory infections leading to destruction of airways secondary to inflammation. We investigated whether the addition of 6-months' twice-weekly azithromycin to the existing treatment regimen in patients with pulmonary bronchiectasis decreased the number of exacerbations and improved pulmonary function compared with a similar period of time without concurrent azithromycin. METHODS: Thirty patients with high-resolution computed tomography scan-confirmed bronchiectasis were to be recruited. In random order, patients received usual medications for 6 months, and usual medications plus oral azithromycin 500mg twice weekly for 6 months. Patients receiving azithromycin first had a 1-month washout period prior to entering the second phase. Patients recorded weekly peak flow (PF) measurements. Pulmonary function tests (PFTs), 24-hour sputum volume, and needs for intervention with medication or ancillary support were collected at baseline and every 3 months. Exacerbation incidence and sputum volume measurements were compared from baseline to the end of each study phase. RESULTS: Twelve patients were enrolled; 11 were included in the analysis. Owing to randomization, most patients received the azithromycin first, which was fairly well tolerated. PFTs did not change significantly during either study phase and PFs appeared to remain stable during azithromycin therapy and throughout the subsequent control phase. Azithromycin significantly decreased the incidence of exacerbations compared with usual medications (5 vs 16; p = 0.019). Mean 24-hour sputum volume significantly decreased (15% [p = 0.005]) during the active treatment phase, and remained decreased during the control phase (p = 0.028). Subjectively, patients reported increased energy and quality of life while receiving treatment with azithromycin. CONCLUSIONS: The addition of twice-weekly azithromycin significantly decreased the incidence of exacerbation and 24-hour sputum volume and may have stabilized the PFTs and PFs in this 11-patient pilot study. The results of this study justify further investigation of adding azithromycin to the treatment regimens of patients with bronchiectasis for its disease-modifying effects.

Aged↗
PubMed2003

Pharmacokinetics and tissue concentrations of azithromycin in ball pythons (Python regius).

OBJECTIVE: To determine pharmacokinetics and tissue concentrations of azithromycin in ball pythons (Python regius) after IV or oral administration of a single dose. ANIMALS: 2 male and 5 female ball pythons. PROCEDURES: Using a crossover design, each snake was given a single dose of azithromycin (10 mg/kg) IV. After a 4-week washout period, each snake was given a single dose of azithromycin (10 mg/kg) orally. Blood samples were collected prior to dose administration and 1, 3, 6, 12, 24, 48, 72, and 96 hours after azithromycin administration. Azithromycin was quantitated by use of liquid chromatography-mass spectrometry. RESULTS: After IV administration, azithromycin had an apparent volume of distribution of 5.69 L/kg and a plasma clearance of 0.19 L/h/kg. Harmonic means for the terminal half-life were 17 hours following IV administration and 51 hours following oral administration. Mean residence times were 37 and 94 hours following IV and oral administration, respectively. Following oral administration, azithromycin had a peak plasma concentration (Cmax) of 1.04 microg/mL, a time to Cmax of 8.4 hours, and a prolonged mean absorption time of 57 hours. Mean oral bioavailability was 77%. Tissue concentrations ranged from 4 to 140 times the corresponding plasma concentration at 24 and 72 hours after azithromycin administration. CONCLUSIONS AND CLINICAL RELEVANCE: Azithromycin is well absorbed and tolerated by ball pythons. On the basis of plasma pharmacokinetics and tissue concentration data, we suggest an azithromycin dosage in ball pythons of 10 mg/kg, orally, every 2 to 7 days, depending upon the site of infection and susceptibil ity of the infective organism.

Animals↗
PubMed1992

Clarithromycin and azithromycin: new macrolide antibiotics.

The chemistry, mechanism of action, antimicrobial spectrum, pharmacokinetics, clinical efficacy, adverse effects, drug interactions, and dosage and administration of clarithromycin and azithromycin are described. Clarithromycin and azithromycin are new macrolide antibiotics that are similar in structure to erythromycin. Compared with erythromycin, clarithromycin demonstrates increased activity against Staphylococcus aureus, streptococci, Legionella pneumophila, Moraxella catarrhalis, and Chlamydia trachomatis. Clarithromycin also has in vitro activity against Mycobacterium avium complex (MAC) and Toxoplasma gondii. Azithromycin has increased gram-negative activity compared with erythromycin, including activity against Haemophilus influenzae, while maintaining activity against gram-positive organisms. Azithromycin also has activity against sexually transmitted organisms including Chlamydia trachomatis. The pharmacokinetic profiles of clarithromycin and azithromycin are characterized by good oral bioavailability, excellent tissue penetration and persistence, and long elimination half-lives, which allow for once-daily or twice-daily dosing. Initial data show that clarithromycin and azithromycin are effective for the treatment of upper-respiratory-tract and lower-respiratory-tract infections and infections of the skin and skin structures. Azithromycin has been shown to be effective for the treatment of sexually transmitted diseases caused by Chlamydia trachomatis. Clarithromycin and azithromycin have been used to treat MAC and Toxoplasma infections in patients with the acquired immunodeficiency syndrome. The most frequently reported adverse effects for both agents have been nausea, diarrhea, and abdominal pain. Oral formulations of clarithromycin and azithromycin have recently been approved by the FDA. Clarithromycin and azithromycin are new macrolide antibiotics that have potential advantages over erythromycin; however, the role of these agents will be better defined as results of more ongoing trials become available for evaluation.

Azithromycin↗
PubMed2005

A double-blind, randomized study of azithromycin compared to chloroquine for the treatment of Plasmodium vivax malaria in India.

Azithromycin has demonstrated activity in a prevention of Plasmodium vivax infection, but no controlled treatment studies have been performed. We conducted a double-blinded trial in P. vivax malaria in which patients were randomized to either azithromycin 1,000 mg q.d. x 3 or chloroquine 600 mg q.d. x 2 then 300 mg on Day 3 followed by primaquine on Days 7 through 20. Eighty-five of 97 (88%) of those on azithromycin and 101 of 102 (99%) of those on chloroquine [difference 11%; 95% CI: -18, -4] were clinically cured at Day 7. The Day 28 results were similar [89% versus 99%, azithromycin versus chloroquine, respectively]. Parasitologic success was seen in 81 of 97 (84%) on azithromycin and 100 of 102 (98%) on chloroquine [difference 14%; 95% CI: -22, -6]. The median parasite clearance time was 55 hours on azithromycin and 20 hours on chloroquine (P < 0.001). Drug-related adverse events were seen in 13 of 98 (13%) on azithromycin and 24 of 102 (24%) on chloroquine (P = 0.062). Resolution of parasitemia was significantly faster with chloroquine compared with azithromycin, but azithromycin was better tolerated. These data provide support for further study of azithromycin to better define its role in the treatment of P. vivax malaria, either alone as second-line treatment or in combination with other active therapies.

Adult↗
PubMed1995

Azithromycin for empirical treatment of the nongonococcal urethritis syndrome in men. A randomized double-blind study.

OBJECTIVE: To evaluate the use of single-dose azithromycin for empirical treatment of nongonococcal urethritis. DESIGN: Randomized, double-blind, multicenter trial comparing azithromycin vs doxycycline therapy, with a 2:1 randomization ratio. Patients were evaluated clinically and microbiologically for Chlamydia trachomatis and Ureaplasma urealyticum infection before therapy and at 2 and 5 weeks after study entry. SETTING: Eleven sexually transmitted disease clinics throughout the United States. PATIENTS: A total of 452 men aged 18 years or older with symptomatic nongonococcal urethritis of less than 14 days' duration. INTERVENTION: Patients were treated with either 1.0 g of azithromycin as a single oral dose or 100 mg of doxycycline taken orally twice daily for 7 days. MAIN OUTCOME MEASURES: Clinical resolution of symptoms and signs of nongonococcal urethritis, microbiological cure of C trachomatis and U urealyticum, and occurrence of adverse experiences. RESULTS: Of the 452 patients enrolled, 248 in the azithromycin-treated group and 123 in the doxycycline-treated group were evaluable for clinical response. The two treatment groups were comparable in terms of age, weight, ethnic distribution, sexual preference, sexual activity, and history of prior nongonococcal urethritis or gonorrhea. Sixteen percent of the azithromycin group and 24% of the doxycycline group were culture positive for C trachomatis before therapy, while 38% and 28%, respectively, were culture positive for U urealyticum. The cumulative clinical cure rate was 81% (95% confidence interval [CI], 75% to 85%) in the azithromycin-treated group and 77% (95% CI, 69% to 84%) in the doxycycline-treated group. Clinical cure rates in the two groups were also comparable when patients were stratified by presence or absence of infection with C trachomatis or U urealyticum prior to therapy. Among those infected with C trachomatis, overall microbiological cure rates were 83% (95% CI, 65% to 94%) for azithromycin-treated patients (n = 30) and 90% (95% CI, 68% to 98%) for doxycycline-treated patients (n = 21). Among those infected with U urealyticum, overall microbiological cure rates were 45% (95% CI, 34% to 57%) for azithromycin-treated patients (n = 75) and 47% (95% CI, 30% to 65%) for doxycycline-treated patients (n = 32). Adverse reactions were generally mild to moderate and occurred in 23% of the azithromycin-treated group and 29% of the doxycycline-treated group. CONCLUSIONS: For empirical treatment of the acute nongonococcal urethritis syndrome in men, a single oral dose of azithromycin was as effective as a standard 7-day course of doxycycline in achieving clinical cure. Further, clinical cure rates were comparable with either regimen, regardless of the presence or absence of Chlamydia or Ureaplasma infection.

Adult↗
PubMed2006

Effect of telithromycin and azithromycin on nasopharyngeal bacterial flora in patients with acute maxillary sinusitis.

OBJECTIVE: To explore the efficacy of the ketolide telithromycin compared with azithromycin in eradicating S pneumoniae from the nasopharynx of adults with acute maxillary sinusitis. The growing resistance of Streptococcus pneumoniae to penicillin and macrolides brought about the development of a new class of antibiotics-the ketolides-that are effective against resistant pneumococci. SETTING: Otolaryngology clinic. PATIENTS: One-hundred five patients with acute maxillary sinusitis. INTERVENTIONS: Nasopharyngeal cultures were obtained before therapy and 10 to 12 days after initiation of treatment. Fifty-nine patients were treated with 500 mg of azithromycin daily for 3 days and 46 were treated with 800 mg of telithromycin daily for 5 days. RESULTS: Sixty-seven potential pathogens were recovered prior to initiation of therapy in 57 patients, 32 treated with telithromycin and 25 treated with azithromycin: S pneumoniae (31 isolates), Haemophilus influenzae (non-type b) (13), Staphylococcus aureus (8), Streptococcus pyogenes (8), and Moraxella catarrhalis (7). The distribution of the pathogens was similar in both groups. The number of S pneumoniae isolates in the azithromycin group was reduced following treatment from 14 to 8 (43% reduction), and 5 of these 8 isolates were resistant to azithromycin. In contrast, the number of S pneumoniae isolates in the telithromycin group was reduced following treatment from 17 to 1 (94% reduction) (P < .01). This isolate was susceptible to azithromycin and telithromycin. No differences were noted in the eradication rate of all of the other potential pathogens, which were all susceptible to both azithromycin and telithromycin. Development of resistance to the antimicrobial agents used (defined as increase in the minimal inhibitory concentration by at least 2 tubes) was found only in 5 isolates (4 S pneumoniae and 1 H influenzae) recovered only from patients who received azithromycin (P < .05). CONCLUSION: These data illustrate the superiority of telithromycin to azithromycin in the eradication of S pneumoniae from the nasopharynx.

Acute Disease↗
PubMed1991

The effects of an antacid or cimetidine on the serum concentrations of azithromycin.

The effects of an antacid and of cimetidine on the serum concentrations of azithromycin were examined in volunteers. Ten subjects were given 500 mg azithromycin alone and immediately after being given 30 mL Maalox (Rorer, Fort Washington, PA) in a crossover design. There were no statistically significant differences in Tmax or AUC0-48 after administration of azithromycin alone or with antacid, but mean values of Cmax were reduced by 24% (P = .015). Thus, although Cmax was decreased, the extent of absorption of azithromycin was not affected by coadministration with an antacid. Two groups of six volunteers were given 500 mg azithromycin on day 1. On day 8, one group was given 800 mg cimetidine 2 hours before a dose of azithromycin; the remaining group received placebo before azithromycin. There were no differences in the pharmacokinetic parameters produced by administration with cimetidine or placebo, relative to those on day 1. Thus, cimetidine administered 2 hours before a dose of azithromycin had no apparent effect on the serum concentrations of azithromycin.

Administration, Oral↗
PubMed1995

Efficacy and safety of azithromycin versus benzylpenicillin or erythromycin in community-acquired pneumonia.

Azithromycin, a recently introduced antibiotic, offers the potential advantages of short-course administration and lower toxicity compared to other macrolides. Approved for the treatment of mild pneumonia, this drug was investigated in a study of patients hospitalized for community-acquired pneumonia. In an open-labelled randomized study, oral azithromycin was compared with intravenous benzylpenicillin in patients suspected to have pneumococcal pneumonia. Azithromycin was also compared with erythromycin, both administered orally, in all other patients. Three hundred thirty-four patients with community-acquired pneumonia were hospitalized, 108 of whom were randomized; 104 could be evaluated. A need for intravenous therapy was the most common reason for exclusion. In the pneumococcal group, 35 patients received azithromycin and 29 benzylpenicillin. The clinical and radiological success rate achieved with azithromycin (83%) was considerably higher than that achieved with benzylpenicillin (66%), though the difference was not significant. In the non-pneumococcal group, 19 patients received azithromycin and 21 erythromycin; no differences in the success rate were found (79% and 76%, respectively). Eight patients on azithromycin had a blood culture positive for Streptococcus pneumoniae; in three of these patients therapy was changed. None of the five patients with pneumococcal bacteraemia who received benzylpenicillin required a change in therapy. It is concluded that oral azithromycin, administered as short-course therapy, is an appropriate antibiotic for treating patients with community-acquired pneumonia. However, it is not yet certain that azithromycin is a good choice for patients with pneumococcal bacteraemia.

Administration, Oral↗
PubMed2003

The macrolide antibiotic azithromycin interacts with lipids and affects membrane organization and fluidity: studies on Langmuir-Blodgett monolayers, liposomes and J774 macrophages.

The macrolide antibiotic azithromycin was shown to markedly inhibit endocytosis. Here we investigate the interaction of azithromycin with biomembranes and its effects on membrane biophysics in relation to endocytosis. Equilibrium dialysis and 31P NMR revealed that azithromycin binds to lipidic model membranes and decreases the mobility of phospholipid phosphate heads. In contrast, azithromycin had no effect deeper in the bilayer, based on fluorescence polarization of TMA-DPH and DPH, compounds that, respectively, explore the interfacial and hydrophobic domains of bilayers, and it did not induce membrane fusion, a key event of vesicular trafficking. Atomic force microscopy showed that azithromycin perturbed lateral phase separation in Langmuir-Blodgett monolayers, indicating a perturbation of membrane organization in lateral domains. The consequence of azithromycin/ phospholipid interaction on membrane endocytosis was next evaluated in J774 macrophages by using three tracers with different insertion preferences inside the biological membranes and intracellular trafficking: C6-NBD-SM, TMA-DPH and N-Rh-PE. Azithromycin differentially altered their insertion into the plasma membrane, slowed down membrane trafficking towards lysosomes, as evaluated by the rate of N-Rh-PE self-quenching relief, but did not affect bulk membrane internalization of C6-NBD-SM and TMA-DPH. Azithromycin also decreased plasma membrane fluidity, as shown by TMA-DPH fluorescence polarization and confocal microscopy after labeling by fluorescent concanavalin A. We conclude that azithromycin directly interacts with phospholipids, modifies biophysical properties of membrane and affects membrane dynamics in living cells. This antibiotic may therefore help to elucidate the physico-chemical properties underlying endocytosis.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2000

[Azithromycin: an anti-inflammatory effect in chronic recurrent multifocal osteomyelitis? A preliminary report].

In this preliminary communication we report our experience with Azithromycin in patients with Chronic Recurring Multifocal Osteomyelitis (CRMO). Seven out of 13 patients, mainly teenager, showed a fast clinical improvement after they were started on Azithromycin. The immediate therapeutic effect of Azithromycin in patients with CRMO was surprising and lead us to the hypothesis that Azithromycin could have an antiphlogistic in addition to it's antibiotic effect in this disease setting. In patients with reactive chronic pelvic osteomyelitis Azithromycin obviously had a direct influence on the sympathic coxitis. Half of the patients reported an immediate reduction of pain and a significant improvement in range of movement after they were started on Azithromycin. In all cases the clinical and radiographic signs on MRI showed a reduction of the inflammatory process. Experimental animal models have recently shown that macrolids have independent additional antiinflammatory and immunomodulatory effects. The assumed local immunomodulatory effect of Azithromycin potentially is an additional activity to the already known synergistic antimicrobial and antiinflammatory effect. Right now we are in the process of collecting data from patients with SAPHO Syndrome who underwent bone-biopsies for microbiologic and histomorphologic investigations. All patients with the growth of propionibacterium acnes were started on a long-term antibiotic therapy with Azithromycin. This study will possibly help to answer the question of the additional antiphogistic/immunomodulatory effect of Azithromycin in this disease entity and the related CRMO.

Adolescent↗
PubMed2006

Effect of the antibiotic azithromycin on thermotropic behavior of DOPC or DPPC bilayers.

Azithromycin is a macrolide antibiotic known to bind to lipids and to affect endocytosis probably by interacting with lipid membranes [Tyteca, D., Schanck, A., Dufrene, Y.F., Deleu, M., Courtoy, P.J., Tulkens, P.M., Mingeot-Leclercq, M.P., 2003. The macrolide antibiotic azithromycin interacts with lipids and affects membrane organization and fluidity: studies on Langmuir-Blodgett monolayers, liposomes and J774 macrophages. J. Membr. Biol. 192, 203-215]. In this work, we investigate the effect of azithromycin on lipid model membranes made of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Thermal transitions of both lipids in contact with azithromycin are studied by (31)P NMR and DSC on multilamellar vesicles. Concerning the DPPC, azithromycin induces a suppression of the pretransition whereas a phase separation between the DOPC and the antibiotic is observed. For both lipids, the enthalpy associated with the phase transition is strongly decreased with azithromycin. Such effects may be due to an increase of the available space between hydrophobic chains after insertion of azithromycin in lipids. The findings provide a molecular insight of the phase merging of DPPC gel in DOPC fluid matrix induced by azithromycin [Berquand, A., Mingeot-Leclercq, M.P., Dufrene, Y.F., 2004. Real-time imaging of drug-membrane interactions by atomic force microscopy. Biochim. Biophys. Acta 1664, 198-205] and could help to a better understanding of azithromycin-cell interaction.

Anti-Bacterial Agents↗
PubMed1999

Efficacy of azithromycin in prevention of Pneumocystis carinii pneumonia: a randomised trial. California Collaborative Treatment Group.

BACKGROUND: Azithromycin in combination with sulphonamides is active against Pneumocystis carinii pneumonia (PCP) in animals. We assessed the clinical efficacy of azithromycin for PCP prophylaxis in human beings. METHODS: We identified HIV-1-infected patients with PCP during a prospective randomised trial comparing azithromycin, rifabutin, and the two drugs in combination for prevention of disseminated Mycobacterim avium infection. Patients had CD4-cell counts less than 100/microL at entry and received PCP prophylaxis according to the standard practice of their clinician. Analysis was by intention to treat. FINDINGS: Patients receiving azithromycin, either alone (n=233) or in combination with rifabutin (n=224), had a 45% lower risk of developing PCP than those receiving rifabutin alone (n=236; p=0.008). Compared with rifabutin alone, hazard ratio for azithromycin was 0.54 (95% CI 0.32-0.94), for azithromycin plus rifabutin was 0.55 (0.32-0.94), and for regimens containing azithromycin was 0.55 (0.35-0.86). The most common side-effects involved the gastrointestinal tract with dose-limiting toxicities, and were mainly seen in patients receiving combination therapy. INTERPRETATION: Azithromycin as prophylaxis for M. avium complex disease provides additional protection against P. carinii over and above that of standard PCP prophylaxis. Use of azithromycin is beneficial only as primary prophylaxis.

AIDS-Related Opportunistic Infections↗
PubMed2002

A multicenter, open-label, randomized comparison of levofloxacin and azithromycin plus ceftriaxone in hospitalized adults with moderate to severe community-acquired pneumonia.

BACKGROUND: Changing etiologic patterns and the growing problem of antimicrobial resistance, particularly an increase in macrolide-resistant pneumococcal bacteremia, are causing physicians to adopt new approaches to the treatment of community-acquired pneumonia (CAP). OBJECTIVE: The relative efficacy and tolerability of levofloxacin monotherapy and azithromycin and ceftriaxone combination therapy were assessed in hospitalized adults with moderate to severe CAP. METHODS: This Phase IV, multicenter, open-label, randomized trial compared 2 treatment regimens: (1) levofloxacin 500 mg PO or IV q24h, and (2) azithromycin 500 mg IV q24h for > or = 2 days plus ceftriaxone 1 g IV q24h for 2 days, followed by an optional transition to azithromycin 500 mg PO q24h at the investigator's discretion. The total duration of therapy was to be a minimum of 10 days in both treatment groups. Ceftriaxone was included in the initial azithromycin regimen to ensure coverage against pneumococcal bacteremia. RESULTS: Of 236 patients in the intent-to-treat population, completion or withdrawal information was available for 110 patients in the levofloxacin group and 114 in the azithromycin group. Baseline demographic and disease characteristics were comparable between groups. At the end of treatment, the clinical success rate (cured + improved) in clinically evaluable patients was 94.1% in the levofloxacin group and 92.3% in the azithromycin group. The respective posttherapy microbiologic eradication rates were 89.5% and 92.3%. Levofloxacin was as well tolerated as azithromycin, with an incidence of drug-related adverse events (AEs) for all body systems of 5.3% and 9.3%, respectively. None of the drug-related AEs were considered serious [corrected]. CONCLUSIONS: In this study in hospitalized patients with moderate to severe CAP, levofloxacin monotherapy was at least as effective as a combination regimen of azithromycin and ceftriaxone in providing coverage against the current causative pathogens in CAP. In addition, levofloxacin was as well tolerated as the combination of azithromycin and ceftriaxone.

Adult↗
PubMedDate not supplied

Azithromycin versus amoxicillin/clavulanate in the treatment of acute sinusitis.

PURPOSE: To compare the efficacy and tolerability of a 3-day course of azithromycin with a 10-day course of amoxicillin/clavulanic acid in the treatment of acute sinusitis in adults. PATIENTS AND METHODS: One hundred adult patients with acute sinusitis were included in an open, randomized study. Clinical diagnosis of sinusitis was confirmed by nasal endoscopy, sinus radiography, and (when possible) by culture of sinus aspirate. Patients were randomized to receive azithromycin (500 mg once daily for 3 days) or amoxicillin/clavulanate (625 mg every 8 hours for 10 days). RESULTS: A significantly faster resolution of signs and symptoms of sinusitis was observed in the azithromycin-treated patients. By the end of therapy (days 10-12), 95% of the patients in the azithromycin group and 74% in the amoxicillin/clavulanate group were cured. The remaining patients' conditions were improved. By the follow-up visit, cure was achieved in 98% of the azithromycin-treated patients, and 91% of the amoxicillin/clavulanate-treated patients. Treatment failure was observed in three patients from the amoxicillin/clavulanate group, and relapse occurred in one patient from each group. Bacteriologic eradication was achieved in 23 of 23 and 21 of 24 patients treated with azithromycin and amoxicillin/clavulanate, respectively. Both drugs were well tolerated. Two patients (4%) from the azithromycin group and five patients (10%) from the amoxicillin/clavulanate group reported mild gastrointestinal disturbances. CONCLUSIONS: In adults with acute sinusitis, a 3-day course of azithromycin was as effective and well tolerated as a 10-day course of amoxicillin/clavulanic acid. A significantly simpler dosage regimen and faster clinical effect were the advantages of azithromycin.

Acute Disease↗
PubMed2002

Pharmacokinetics of azithromycin in foals after i.v. and oral dose and disposition into phagocytes.

The properties of azithromycin suggest that it may be an alternative to erythromycin for treatment of Rhodococcus equi pneumonia in foals. To investigate this possibility, the disposition of azithromycin in plasma, polymorphonuclear leukocytes (PMN), and alveolar cells was examined after a single administration in foals. Azithromycin suspension was administered orally (p.o.) at a dose of 10 mg/kg to five healthy 2-3-month-old foals. Two weeks later, azithromycin for injection was administered by intravenous (i.v.) infusion at a dose of 5 mg/kg to the same foals. Plasma samples were collected after p.o. and i.v. administration. Peripheral blood PMN and bronchoalveolar lavage fluid and alveolar cells were collected after p.o. administration. Azithromycin concentrations were determined by reverse-phase high-performance liquid chromatography (HPLC) with coulometric electrochemical detection. Azithromycin p.o. absorption was variable with a mean systemic availability of 39% (+/-20%). The plasma half-life was 16 and 18.3 h after i.v. and p.o. administration, respectively. Azithromycin had a very large volume of distribution (V(d)) of 11.6 L/kg [V(d(ss))] and 12.4 L/kg [V(d(area))]. The large V(d) can be attributed to high tissue and intracellular concentrations, exhibited by the high concentration of azithromycin in PMN and alveolar cells. The PMN half-life was 49.2 h. Dosage of 10 mg/kg of azithromycin p.o. once daily for foals with R. equi pneumonia is recommended for further study.

Actinomycetales Infections↗
PubMed2001

Azithromycin, a lysosomotropic antibiotic, impairs fluid-phase pinocytosis in cultured fibroblasts.

The dicationic macrolide antibiotic azithromycin inhibits the uptake of horseradish peroxidase (HRP) by fluid-phase pinocytosis in fibroblasts in a time- and concentration-dependent fashion without affecting its decay (regurgitation and/or degradation). The azithromycin effect is additive to that of nocodazole, known to impair endocytic uptake and transport of solutes along the endocytic pathway. Cytochemistry (light and electron microscopy) shows a major reduction by azithromycin in the number of HRP-labeled endocytic vesicles at 5 min (endosomes) and 2 h (lysosomes). Within 3 h of exposure, azithromycin also causes the appearance of large and light-lucentlelectron-lucent vacuoles, most of which can be labeled by lucifer yellow when this tracer is added to culture prior to azithromycin exposure. Three days of treatment with azithromycin result in the accumulation of very large vesicles filled with pleiomorphic content, consistent with phospholipidosis. These vesicles are accessible to fluorescein-labeled bovine serum albumin (FITC-BSA) and intensively stained with filipin, indicating a mixed storage with cholesterol. The impairment of HRP pinocytosis directly correlates with the amount of azithromycin accumulated by the cells, but not with the phospholipidosis induced by the drug. The proton ionophore monensin, which completely suppresses azithromycin accumulation, also prevents inhibition of HRP uptake. Erythromycylamine, another dicationic macrolide, also inhibits HRP pinocytosis in direct correlation with its cellular accumulation and is as potent as azithromycin at equimolar cellular concentrations. We suggest that dicationic macrolides inhibit fluid-phase pinocytosis by impairing the formation of pinocytic vacuoles and endosomes.

Adenosine Triphosphate↗
PubMed2006

Azithromycin combination therapy with artesunate or quinine for the treatment of uncomplicated Plasmodium falciparum malaria in adults: a randomized, phase 2 clinical trial in Thailand.

BACKGROUND: Because antimalarial drug resistance is spreading, there is an urgent need for new combination treatments for malaria, which kills >1 million people every year. Azithromycin is a macrolide antibiotic that is particularly attractive as an antimalarial because of its safety in children and the extensive experience with its use during pregnancy. METHODS: We undertook a randomized, controlled, 28-day inpatient trial involving patients with acute, uncomplicated Plasmodium falciparum malaria. We compared the safety and efficacy of 2 azithromycin-artesunate combinations and 2 azithromycin-quinine regimens in adults with malaria. Treatments were as follows: cohort 1 received 3 days of azithromycin (750 mg twice daily) plus artesunate (100 mg twice daily), cohort 2 received 3 days of azithromycin (1000 mg once daily) plus artesunate (200 mg once daily), cohort 3 received 3 days of azithromycin (750 mg twice daily) plus quinine (10 mg/kg twice daily), and cohort 4 received 3 days of azithromycin (500 mg 3 times daily) plus quinine (10 mg/kg 3 times daily). The enrollment target was 25 evaluable subjects per group. RESULTS: The 28-day cure rates were similarly high in the artesunate and the standard-dose quinine cohorts: 92.0% (95% confidence interval [CI], 74.0%-99.0%), 88.9% (95% CI, 70.8%-97.6%), and 92.0% (95% CI, 74.0%-99.0%), for cohorts 1, 2, and 4, respectively. Late R1 treatment failures were seen in each of the artesunate and the standard-dose quinine cohorts. The cure rate for cohort 3 was 73.3% (95% CI, 44.9%-92.2%). In this cohort, 3 early treatment failures led to the termination of enrollment after 16 subjects had been enrolled. With mean parasite and fever clearance times (+/-SD) of 34+/-13 h and 20+/-20 h, the artesunate combinations were found to have led to a significantly (P<.001) faster clinical and parasitological improvement than occurred in the quinine cohorts (74+/-32 h and 43+/-37 h, respectively). Treatment-related adverse events were significantly more common in the quinine cohorts (P<.001). No deaths or drug-related serious adverse events were observed. In vitro results suggest that the treatment failures--particularly in the low-dose quinine cohort--were associated with decreased susceptibility to quinine, as well as with mefloquine cross-resistance. CONCLUSIONS: These data suggest that azithromycin-artesunate, even when given only once daily for 3 days, and azithromycin-quinine, given 3 times daily, are safe and efficacious combination treatments for uncomplicated falciparum malaria, and they deserve additional study in special patient populations.

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