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An evaluation of tolerance of roxithromycin in adults.

This review deals with tolerance of a new macrolide, roxithromycin from data collected from a number of studies in adults. A total of 2917 adults, 2519 given roxithromycin 150 mg bid, were recruited into 17 multicentre comparative or non-comparative studies. Nine studies were double-blind, against doxycycline, erythromycin estolate (EES), lymecycline or cephradine. Overall the drug was well tolerated: side-effects possibly or probably related to roxithromycin were noted in only 4.1% (120/2917) of all patients, and in 3.1% (15/480) of elderly subjects. The gastrointestinal tolerance of roxithromycin was significantly better than that of doxycycline in four trials, and better than that of erythromycin ethylsuccinate in one study. The incidence of drug-related liver function test abnormalities following roxithromycin therapy was low and compared favourably with data published on erythromycin. Roxithromycin shows a satisfactory safety profile at the recommended daily dosage of 150 mg bid in adults.

Adult↗

Roxithromycin alone and in combination with sulphamethoxazole against Haemophilus influenzae.

Haemophilus influenzae is only moderately susceptible to erythromycin but previous studies in vitro and in vivo have shown that it is fully susceptible when erythromycin is combined with sulphonamides. The purpose of this study was to evaluate whether the activity of the new macrolide antibiotic roxithromycin was improved after combination with sulphamethoxazole. One hundred and eighty fresh clinical isolates of Haemophilus influenzae, comprising 74 ampicillin-susceptible, beta-lactamase negative, and 106 ampicillin-resistant, beta-lactamase positive, strains, were tested for their susceptibility to erythromycin, roxithromycin, sulphamethoxazole, erythromycin-sulphamethoxazole and roxithromycin-sulphamethoxazole in a fixed ratio of 1:19. Bacteriostatic and bactericidal synergy was found between roxithromycin and sulphamethoxazole more commonly than between erythromycin and sulphamethoxazole. Antagonism, was less common between roxithromycin and sulphamethoxazole than erythromycin and sulphamethoxazole. These results suggest that the in-vitro activity of roxithromycin is improved by combination with sulphamethoxazole, making this combination more attractive in the oral therapy of infections due to H. influenzae.

Culture Media↗

Toxicity, uptake, and subcellular distribution in rat hepatocytes of roxithromycin, a new semisynthetic macrolide, and erythromycin base.

Rat hepatocytes were used to study the toxicity of a new semisynthetic macrolide, roxithromycin, in comparison with erythromycin base and erythromycin estolate. Roxithromycin caused lactate dehydrogenase leakage close to that of erythromycin estolate and higher than erythromycin base after 21 h of exposure to the drugs. This effect was, at least in part, explained by the higher uptake: roxithromycin was two to three times more concentrated by liver cells than erythromycin base. For both roxithromycin and erythromycin base, the uptake depended on time, temperature, and extracellular antibiotic concentration. The accumulated macrolides egressed rapidly when cells were incubated in antibiotic-free medium. No uptake and no loss of accumulated drugs were observed at 4 degrees C. After accumulation by hepatocytes, roxithromycin and erythromycin base underwent similar subcellular distribution, mostly concentrating in cytosol and lysosomes. The small amount accumulated in the other particulate fractions followed the order mitochondria much greater than nuclei greater than microsomes. Roxithromycin, however, was less concentrated than erythromycin base in the microsomes.

Animals↗

Bactericidal activity of ofloxacin versus roxithromycin in the treatment of Streptococcus pneumoniae.

Ofloxacin is highly active against Gram-negative aerobic bacilli, but moderately active against Gram-positive cocci. The minimal inhibitory concentrations (MICs) against Streptococcus pneumoniae range between 1 and 2 mg/L. MICs of roxithromycin (RU 28965) against S. pneumoniae range between 0.004 and 0.03 mg/L, but Gram-negative bacilli are resistant. The bactericidal activities of ofloxacin and roxithromycin were evaluated against 15 strains of S. pneumoniae, which were isolated recently from clinical specimens. Killing activity was evaluated under conditions simulating serum pharmacokinetic parameters. Initial concentrations were 10 mg/L for roxithromycin and 2 mg/L for ofloxacin, and the half-life was 6 hours for both compounds. Under these conditions, roxithromycin was rapidly bactericidal. The speed at which pneumococci were killed was faster with roxithromycin than with ofloxacin. No regrowth was seen with roxithromycin, but regrowth occurred in 8 of 15 strains with ofloxacin.

Anti-Bacterial Agents↗

Roxithromycin. A review of its antibacterial activity, pharmacokinetic properties and clinical efficacy.

Roxithromycin is an acid-stable orally administered antibacterial macrolide structurally related to erythromycin. It has an in vitro antibacterial profile similar to that of erythromycin, with activity against Staphylococcus aureus, S. epidermidis, Streptococcus pneumoniae, S. pyogenes, Branhamella catarrhalis, Mycoplasma pneumoniae, Legionella pneumophila, Chlamydia trachomatis, Gardnerella vaginalis, Haemophilus ducreyi, some anaerobes and other less common pathogens. Roxithromycin has a pharmacokinetic profile that is characterised by excellent enteral absorption achieving high concentrations in most tissues and body fluids. The results of clinical studies with roxithromycin have confirmed the potential for its use in a variety of infections, which was suggested by its antibacterial activity in vitro and pharmacokinetic profile. Clinical efficacy has been confirmed in the treatment of respiratory tract infections, including community-acquired and atypical pneumonias, ear, nose and throat infections, genitourinary tract infections, and skin and soft tissue infections. In a relatively small number of patients roxithromycin has generally been shown to be as effective as erythromycin and other appropriate antibacterial drugs in some of the above indications. Roxithromycin is well tolerated and has less potential than erythromycin to produce clinically significant drug interactions. Thus, roxithromycin is an orally active drug which should prove a useful alternative when selecting antibacterial therapy for indications where macrolides are appropriate.

Female↗

Roxithromycin antagonism with essential and trace elements.

In order to ascertain the role of various essential and trace element complexation on the antibacterial activity of various macrolide antibiotics, the synergistic or antagonistic behavior of roxithromycin metal complexes have been studied and compared with the parent drug. Metal complexes of roxithromycin with magnesium, calcium, chromium, manganese, iron, cobalt, nickel, copper, zinc and cadmium have been investigated for their antibacterial activity and compared with roxithromycin by observing the changes in minimum inhibitory concentration (MIC) and by measuring the zone of inhibition of complexes against both Gram-negative and Gram-positive microorganisms. Various microorganisms used were Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Salmonella typhi, Proteus vulgaris, Shigella dysentery, Klebsiella pneumoniae and Staphylococcus epidermidis. For MIC observation, serial dilution method was employed and zone sizes were determined by diffusion disk method. Our investigations divulge that formation of roxithromycin complexes results in antagonistic behavior against few microorganisms where in MIC is increased with respect to the parent drug, while against most of the microorganism, there was no effect on the MIC of the roxithromycin metal complexes with respect to parent roxithromycin.

Journal Article↗

[Interaction of roxithromycin with human polymorphonuclear neutrophils in vitro and ex vivo].

Roxithromycin (RU 28965) a new semisynthetic macrolide has been reported to display an antibacterial spectrum and activity in vitro similar to those of others macrolides. However, roxithromycin seems more efficient than erythromycin in in vivo experimental infections (mice). We have previously reported that roxithromycin increases the ability of human neutrophils (PMN) for bactericidal activity (S. aureus) or phagocytosis (K. pneumoniae) in vitro without altering other PMN functional parameters. In this study, roxithromycin (single dose-300 mg) was given to 6 human volunteers. The neutrophils collected 90 min after ingestion display a significant increased ability to phagocytose and kill S. aureus and K. pneumoniae. Furthermore chemotaxis, oxidative burst and myeloperoxidase activity of the PMN after roxithromycin ingestion were enhanced compared to those of PMN before ingestion. This discrepancy between immunomodulating effect of roxithromycin in vitro and in vivo outlines the complexity of in vivo experimental models and requires further studies in vivo in particular in patients suffering from sepsis.

Adult↗

The in vitro activity of roxithromycin (RU 28965) compared with four oral antibiotics.

The in vitro activity of roxithromycin (RU 28965), a new semisynthetic macrolide, was compared with that of amoxycillin, cephradine, doxycycline and erythromycin against 160 respiratory and skin isolates including 10 methicillin-resistant Staph. aureus, 10 beta-lactamase-producing Haemophilus influenzae and 30 anaerobes. The MIC determinations were performed by an agar dilution method using a final inoculum of 10(4)-10(5) c.f.u./ml and results were recorded as the lowest concentration of the drug that inhibited visible growth (MIC). All organisms were incubated aerobically at 37 degrees C for 18 h, except anaerobes which were incubated in an anaerobic chamber at 37 degrees C for 48 h. The MICs of roxithromycin against staphylococci (30 strains, 10 of which were erythromycin-resistant, MIC greater than or equal to 2 mg/l) ranged from 0.03 to greater than or equal to 16 mg/l. The MIC90 against erythromycin-sensitive staphylococci was 1.0 mg/l. The MICs of roxithromycin ranged from 0.03-4 mg/l (MIC90 0.25 mg/l) against streptococci (50 strains), from 1 to 32 mg/l (MIC90 8 mg/l) against Haemophilus spp. (40), and from 0.06 to 0.25 mg/l (MIC90 0.125 mg/l) against B. catarrhalis (10). Roxithromycin was less active than erythromycin against fusobacteria (MIC 0.05 to greater than or equal to 128 mg/l) and against Veillonella spp. (MIC greater than 128 mg/l). Roxithromycin was more active than cephradine, doxycycline and amoxycillin against the aerobic organisms (except for amoxycillin against streptococci, where the activity was similar) but less active against the anaerobes examined. Taken together with reported kinetic advantages, these results suggest that roxithromycin may be a useful antibiotic in selected circumstances and studies to determine its efficacy seem indicated.

Aerobiosis↗

Roxithromycin 150 mg b.i.d. versus amoxycillin 500 mg/clavulanic acid 125 mg t.i.d. for the treatment of lower respiratory tract infections in general practice.

Two hundred and forty-two patients over 16 years of age with community-acquired lower respiratory tract infection (LRTI), matched for age and sex, were randomised to receive either roxithromycin 150 mg b.i.d. or amoxycillin 500 mg/clavulanic acid 125 mg t.i.d. for 7 days, with a further 7 days if insufficient response was seen. Clinical efficacy at 7 days was 69% for roxithromycin and 56% for amoxycillin/clavulanic acid (p = 0.05) and at study end it was 91% for both antibiotics. There were fewer second treatment courses in the roxithromycin group (26% vs. 38%, p = 0.04) and a shorter treatment duration (8.29 days vs. 9.34 days, p > 0.05). Twelve patients (9.8%) treated with roxithromycin and 19 (17.1%) treated with amoxycillin/clavulanic acid had adverse effects possibly, or probably, related to the antibiotic. Roxithromycin appears to be a more appropriate choice than amoxycillin/clavulanic acid for the treatment of LRTI in the community given its more appropriate in vitro spectrum, efficacy against most common and atypical pathogens, greater cost-effectiveness, more convenient dosage regimen (b.i.d.), and superior tolerability profile.

Adolescent↗

Potential role of roxithromycin against the Mycobacterium avium complex.

Until the recent experience with azithromycin and clarithromycin, macrolides were not considered to be important agents against mycobacteria. Clinical evidence is now growing that the newer 14 and 15 membered macrolide compounds have therapeutic activity against Mycobacterium avium, Mycobacterium chelonae and Mycobacterium leprae. Several years ago, when evaluating the activity of roxithromycin using one of the more virulent M. avium in our collection, the authors found that roxithromycin exerted a bacteriostatic effect in cultured human macrophages. However, in combination with tumour necrosis factor, which induces macrophage activation, roxithromycin caused enhanced intracellular killing. The significance of this finding is that tumour necrosis factor can be elaborated by activated macrophages during the course of infection. The roxithromycin doses that were chosen for these studies were less than achievable blood levels. More recently, the in vitro effect of roxithromycin against a panel of isolates from AIDS patients has been assessed and it was found that some (but not all) of the inhibitory concentrations, by the T-100 method of Inderlied, are within achievable serum levels. This, however, may not be the basis for anticipating in vivo activity since macrolide compounds are known to be concentrated within cells and particularly within phagolysosomes. Demonstration of effect in an in vitro test system is encouraging, but should be considered only as a preliminary step to careful assessments in experimental animals, such as the beige mouse, and studies in humans.

AIDS-Related Opportunistic Infections↗

Roxithromycin in the treatment of Lyme disease--update and perspectives.

Spirochaetal infections have been successfully treated with penicillin; more recently, erythromycin has been used in cases with known penicillin allergy. The discovery of the spirochaete Borrelia burgdorferi and the elaboration of a new generation of macrolides with properties that differ from older macrolides have led to new ways of treating spirochaetal disease with these compounds. This paper presents data on the in vitro and in vivo efficacy of a combination of roxithromycin and co-trimoxazole against B. burgdorferi. In vitro (checkerboard technique; B. burgdorferi strain B31; modified BSK II medium) it was found that while roxithromycin showed excellent efficacy against B. burgdorferi (MIC 0.031 mg/l), co-trimoxazole had no effect. However, the combination of both chemotherapeutics led to a minor synergistic effect, decreasing the MIC for roxithromycin by one dilution step at concentrations of co-trimoxazole from 256 to 8 mg/l. In addition, a clearly reduced growth of microorganisms was seen at concentrations of roxithromycin as low as 0.015 mg/l in combination with 256 to 4 mg/l co-trimoxazole, when compared to the positive controls. Most interestingly, however, the motility of B. burgdorferi was markedly reduced even when the two drugs were combined at very low concentrations. In an in vivo, non-randomised, open, prospective pilot study it was found that of 17 patients with confirmed late Lyme borreliosis (stage II/III), treated with combined roxithromycin (300 mg b.i.d.) and co-trimoxazole for 5 weeks, 13 (76%) recovered completely by the end of treatment, and four continued to have symptoms on follow-up at 6 and 12 months. This success rate is similar to that seen with i.v. penicillin and ceftriaxone. It appears that the reduced motility of B. burgdorferi makes the pathogen more accessible to the immune system.

Administration, Oral↗

Effect of roxithromycin on the pharmacokinetics of lovastatin in volunteers.

OBJECTIVE: To investigate the influence of concomitant administration of roxithromycin on the plasma pharmacokinetics of lovastatin. METHODS: In an open, randomized, crossover study, 12 healthy volunteers received 80 mg lovastatin orally either alone or concomitantly with 300 mg roxithromycin after 5-day pretreatment with roxithromycin 300 mg daily. Plasma concentrations of lovastatin (lactone and acid) were determined using high-performance liquid chromatography, and the pharmacokinetic parameters were estimated. RESULTS: The mean (+/- SD) pharmacokinetic parameters of lovastatin lactone with and without roxithromycin were maximum concentration (Cmax) 8.49+/-6.80/16.3+/-9.4 ng ml(-1), time to Cmax (tmax) 1.8+/-0.4/1.7+/-0.6 h, terminal plasma half-life (t1/2) 4.3+/-2.0/3.7+/-2.5 h, area under the plasma concentration-time curve from zero to infinity (AUC0-infinity) 53+/-60/85+/-67 ng ml(-1) h. The respective parameters of lovastatin acid were Cmax 24.6+/-13.4/17.8+/-11.0 ng ml(-1), tmax 3.7+/-1.1/4.1+/-0.7 h, t1/2 3.2+/-2.5/4.3+/-2.8 h, AUC0-infinity 149+/-123/105+/-58 ng ml(-1) h. Mean bioavailability of lovastatin lactone was lower and that of lovastatin acid was higher with concomitant treatment. However, the differences were significant only with respect to lovastatin lactone (AUC and Cmax) and Cmax of lovastatin acid. CONCLUSION: Roxithromycin does not influence the pharmacokinetics of lovastatin in such a way that dosage adjustment of lovastatin seems to be necessary during co-administration.

Adult↗

Penetration of roxithromycin into gingival tissue.

Roxithromycin is a new macrolide with an antibacterial spectrum similar to that of erythromycin. Absorption is rapid and complete, resulting in high serum levels and a long half-life. Tissue distribution is extensive and sustained, as shown by the high concentrations measured in the lung, prostate, ovaries, liver, kidney, and skin. In this study, we measured the penetration of roxithromycin into gingival tissue at steady state in 30 patients treated orally with 150 mg every 12 hr for 5 days. Tissue specimens were sampled at 2, 4, 6, 8, or 12 hr (n = 6 each time) after dose 10, and blood samples were taken simultaneously. Serum and tissue concentrations of roxithromycin were measured by high-performance liquid chromatography. The peak serum level, reached 4 hr after dosing, was 6.60 +/- 1.15 micrograms/ml. The peak tissue level was 4.63 +/- 1.84 micrograms/g and was reached after 8 hr. From 4 to 10 hr after dosing, tissue concentrations were greater than 2 micrograms/g, that is, higher than the MIC90 of roxithromycin against most oral pathogens. These data support the use of roxithromycin in the treatment of oral infections.

Absorption↗

A randomized double-blind controlled trial of roxithromycin and cefaclor in the treatment of acute lower respiratory tract infections in general practice.

A multicenter, randomized, double-blind, single-dummy placebo-controlled study is being undertaken by the Research Unit of the Royal New Zealand College of General Practitioners to compare the efficacy and tolerance of 150 mg twice daily roxithromycin with 250 mg three times daily cefaclor in the treatment of 250 general practice patients with acute lower respiratory tract infections (LRTIs). Interim analysis of 200 patients reveals no statistically significant differences in the study parameters. Of the patients on roxithromycin and cefaclor, 83% and 67%, respectively, had a moderate or severe illness. Based on efficacy criteria, 96% of roxithromycin recipients and 99% of cefaclor recipients had a satisfactory or improved response. On an intention-to-treat basis, this was reduced to 95% for both treatment groups. Sputum grading and semiquantitative culturing was performed according to NCCLS standards. The most common isolates in order were Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae. Efficacy for bacteriologically evaluable cases was 87.5% for roxithromycin and 57% for cefaclor. Four patients on roxithromycin (3.9%) and 11 patients on cefaclor (11.3%) withdrew because of side effects probably or possibly related to the study treatment. The study is ongoing.

Acute Disease↗

Roxithromycin versus doxycycline in the treatment of acute exacerbations of chronic bronchitis.

The efficacy and safety of roxithromycin (300 mg once daily) and doxycycline (200 mg once daily) in the treatment of acute exacerbations of chronic bronchitis in general practice were compared in a multicenter, double-blind, double-dummy trial. The data presented here are the results of an interim analysis of 76 patients. A satisfactory clinical response was obtained in 81% of patients treated with roxithromycin and 80% of those treated with doxycycline. Among patients receiving roxithromycin, 12.2% volunteered adverse events, compared with 33% of those receiving doxycycline; the test treatments were considered possibly or probably responsible for the adverse events in 9.8% and 21.2% of cases, respectively. Though patient numbers are too small for statistically significant differences to be detected, we conclude that the results to date suggest that roxithromycin and doxycycline are equivalent in terms of efficacy, but that roxithromycin is better tolerated.

Adult↗

Randomised trial of roxithromycin in non-Q-wave coronary syndromes: ROXIS Pilot Study. ROXIS Study Group.

BACKGROUND: There is serological evidence for an association between Chlamydia pneumoniae and coronary heart disease. We investigated the hypothesis that an antichlamydial macrolide antibiotic, roxithromycin, can prevent or reduce recurrent major ischaemic events in patients with unstable angina. METHODS: The effect of roxithromycin was assessed in a double-blind, randomised, prospective, multicentre, parallel-group, placebo-controlled pilot study of 202 patients with unstable angina or non-Q-wave myocardial infarction. Patients were randomly assigned either roxithromycin 150 mg orally twice a day (n = 102) or placebo orally twice a day (n = 100). The treatment was for 30 days. Patients were followed up for 6 months. We report the primary clinical endpoints (cardiac ischaemic death, myocardial infarction, and severe recurrent ischaemia), assessed at day 31, in 202 patients on an intention-to-treat basis. FINDINGS: A statistically significant reduction in the primary composite triple endpoint rates was observed in the roxithromycin group: p = 0.032. The rate of severe recurrent ischaemia, myocardial infarction, and ischaemic death was 5.4%, 2.2%, and 2.2% in the placebo group and 1.1%, 0%, and 0%, in the roxithromycin group, respectively. No major drug-related adverse effects were observed. INTERPRETATION: Antichlamydial antibiotics may be useful in therapeutic intervention in addition to standard medication in patients with coronary-artery disease. Large-scale trials are needed to confirm these preliminary observations.

Adult↗

Solution conformation of methylated macrolide antibiotics roxithromycin and erythromycin using NMR and molecular modelling. Ribosome-bound conformation determined by TRNOE and formation of cytochrome P450-metabolite complex.

Conformational study of methylated derivatives of macrolide antibiotics roxithromycin (6-OMe-roxithromycin and 6,11-OMe-roxithromycin) has been achieved by NMR in solution and molecular dynamics (MD) simulations and compared to 6-OMe-erythromycin (clarithromycin). A complete conformational study by NMR has been led by determination of homonuclear coupling constants and NOEs. Heteronuclear 1H-13C coupling constants were also measured to investigate the orientation of the sugar moieties with respect to the erythronolide. MD simulations were performed using the crystallographic coordinates as the starting conformation. For each compound, experimental results were compared to calculated conformations in order to identify eventual conformational equilibrium in solution. It is shown that the effect of the methylation is opposite for roxithromycin compared to erythromycin especially on motional properties as the roxithromycin derivatives gain in mobility while the erythromycin derivatives behaves as a more restrained molecule. The study of macrolide-ribosome interactions has been investigated using transferred NOESY 1H NMR experiments and the conformations weakly bound to bacterial ribosomes were determined. Biological interactions of these compounds with membranar liver protein cytochrome P450 was also discussed with regard to their structural properties.

Anti-Bacterial Agents↗

Inhibition of tumor angiogenesis by roxithromycin, a 14-membered ring macrolide antibiotic.

We examined the effects of roxithromycin, a 14-membered ring macrolide antibiotic, on tumor angiogenesis using a mouse dorsal air sac model. The inhibitory effect of roxithromycin was dose-dependent and 100 mg/kg of roxithromycin administered intraperitoneally twice a day reduced the dense capillary network area to about 20% of the control. However, at concentrations of up to 50 microM, roxithromycin had no effect on lung cancer cells and human vascular endothelial cell growth and lung cancer cell production of the angiogenesis-inducing factors interleukin-8 and vascular endothelial growth factor. Roxithromycin at concentrations greater than 20 microM inhibited endothelial cell migration and tube formation.

Animals↗