Population-based meta-analysis of roxithromycin pharmacokinetics: dosing implications of saturable absorption and protein binding

Objectives

The macrolide antibiotic roxithromycin has seen widespread clinical use for several decades; however, no population pharmacokinetic analysis has been published. Early studies indicated saturation of protein binding and absorption at doses within the approved range, which may impact pharmacodynamic target attainment since regimens of 150 mg twice daily and 300 mg once daily are used interchangeably in clinical practice. This study aimed to develop a population-based meta-analysis of roxithromycin pharmacokinetics, and utilize this model to inform optimal dosing regimens.

Methods

Following an extensive search, roxithromycin pharmacokinetic data were collected or digitized from literature publications. Population pharmacokinetic modelling was undertaken with ADAPT. Dosing simulations were performed to investigate differences in exposure and pharmacodynamic target attainment between dosing regimens.

Results

A two-compartment model with saturable absorption described the data ( n  =   63); changes in free drug exposure were simulated using a saturable protein binding model. Simulations indicated that a 300 mg daily regimen achieves a 37% and 53% lower total or free AUC ( f AUC), respectively, compared with 150 mg twice daily. These pharmacokinetic differences translated to significantly lower target attainment ( f AUC/MIC ratio >20) with a 300 mg daily regimen at MICs of 0.5 and 1 mg/L (51% and 7%) compared with patients receiving 150 mg twice daily (82% and 54%).

Conclusions

Roxithromycin displays saturable absorption and protein binding leading to lower exposure and lower target attainment at MICs ≥0.5 mg/L with widely used once-daily dosing regimens, indicating that twice-daily regimens may be preferable for pathogens less susceptible to roxithromycin.

Hepatic Veno-Occlusive Disease Associated with Immunosuppressive Cyclophosphamide Dosing and Roxithromycin

Objective:

To report on a patient developing hepatic veno-occlusive disease while being treated with immunosuppressive doses of cyclophosphamide (≤2 mg/kg).

Case Summary:

A 66-year-old woman with autoimmune hemolytic anemia developed hepatic veno-occlusive disease while being treated with immunosuppressive cyclophosphamide 100 mg/day in combination with roxithromycin (total dose 600 mg/day). After all drugs were stopped, the patient recovered within 2 weeks. The Naranjo probability scale indicated a probable relationship between veno-occlusive disease and treatment with cyclophosphamide in this patient.

Discussion:

Since roxithromycin inhibits CYP3A4, which is involved with cyclophosphamide metabolism, a drug-drug interaction could have been responsible. In addition, roxithromycin is an inhibitor of the drug transporter P-glycoprotein, possibly leading to accumulation of cyclophosphamide in endothelial cells. Alternatively, since cyclophosphamide has been reported to induce apoptosis, roxithromycin could have rendered endothelial cells more vulnerable for apoptosis.

Conclusions:

In specific patients, cyclophosphamide can be associated with hepatic veno-occlusive disease at immunosuppressive doses.

Inhibition of the partial nitritation by roxithromycin and Cu(II)

To facilitate the application of partial nitritation (PN) - anaerobic ammonium oxidation process in nitrogen removal from livestock wastewater, the inhibition of roxithromycin (ROX) and Cu(II) on the PN sludge was examined using a respirometric method. The results showed that the IC50 of ROX and Cu(II) on PN sludge were 346 and 74.3mgL(-1), respectively. The relative specific respiration rate (SRR) of ammonia-oxidizing bacteria (AOB) decreased from 87.4% to 17.7% with the ROX concentration increased from 0 to 500mgL(-1). When the concentration of Cu(II) increased from 0 to 160mgL(-1), the SRRs of AOB and nitrite-oxidizing bacteria decreased by 85.5% and 11.2%, respectively. According to the isobole plots analysis, combined suppression by ROX and Cu(II) was synergistic. Fourier transform infrared spectroscopy analyses showed that ROX exposure altered the positions of CO bonds, and the intensity of the absorption peak at 2100cm(-1) changed under Cu(II) exposure.

A novel RP-HPLC method for the detection and quantification of roxithromycin in topical delivery studies

A novel HPLC method with UV detection for the identification and quantification of roxithromycin (ROX) during in vitro skin penetration studies has been developed and validated. The method proved to be simple and rapid with isocratic elution (flow rate: 1.0 mL/min) of ROX, using a C18 column and UV detection at 205 nm. The mobile phase consisted of 0.06 M potassium di-hydrogen orthophosphate buffer (pH adjusted to 7.4 with sodium hydroxide) and acetonitrile in a 50:50 (v/v) ratio. This method showed linearity across the concentration range of 5 - 1000 μg/mL with a correlation coefficient of 0.9999. An average recovery of 101.78% was obtained. Limit of detection (LOD) and lower limit of quantification (LLOQ) values proved that ROX can still be detected at a concentration level of 0.3 μg/mL and accurately quantified at a concentration of 0.5 μg/mL. The specificity testing during method validation proved that this method is suitable for the accurate detection and quantification of ROX even when combined with different compounds typically used during the formulation of topical delivery systems.

[Myopathy and rhabdomyolysis after treatment with simvastatin, amlodipine, and roxithromycin]

This is a case report of a 71-year-old male with known diabetes, hypertension and diabetic nephropaty who over the course of one year developed an unrecognized myopathy due to concomitant treatment with high-dose simvastatin and amlodipin. Due to rhabdomyolysis he was after seven days of treatment with roxithromycin admitted to hospital with loss of the ability to walk. We wish to raise awareness of the potentially severe side effects of simvastatin and to emphasize that these can be limited by increased attention to patients with risk factors and to interactions with other drugs.

Use of clarithromycin and roxithromycin and risk of cardiac death: cohort study

OBJECTIVE

To assess the risk of cardiac death associated with the use of clarithromycin and roxithromycin.

DESIGN

Cohort study.

SETTING

Denmark, 1997-2011.

PARTICIPANTS

Danish adults, 40-74 years of age, who received seven day treatment courses with clarithromycin (n = 160,297), roxithromycin (n = 588,988), and penicillin V (n = 4,355,309).

MAIN OUTCOME MEASURES

The main outcome was risk of cardiac death associated with clarithromycin and roxithromycin, compared with penicillin V. Subgroup analyses were conducted according to sex, age, risk score, and concomitant use of drugs that inhibit the cytochrome P450 3A enzyme, which metabolises macrolides.

RESULTS

A total of 285 cardiac deaths were observed. Compared with use of penicillin V (incidence rate 2.5 per 1000 person years), use of clarithromycin was associated with a significantly increased risk of cardiac death (5.3 per 1000 person years; adjusted rate ratio 1.76, 95% confidence interval 1.08 to 2.85) but use of roxithromycin was not (2.5 per 1000 person years; adjusted rate ratio 1.04, 0.72 to 1.51). The association with clarithromycin was most pronounced among women (adjusted rate ratios 2.83 (1.50 to 5.36) in women and 1.09 (0.51 to 2.35) in men). Compared with penicillin V, the adjusted absolute risk difference was 37 (95% confidence interval 4 to 90) cardiac deaths per 1 million courses with clarithromycin and 2 (-14 to 25) cardiac deaths per 1 million courses with roxithromycin.

CONCLUSIONS

This large cohort study found a significantly increased risk of cardiac death associated with clarithromycin. No increased risk was seen with roxithromycin. Given the widespread use of clarithromycin, these findings call for confirmation in independent populations.

[Impact of treatment with low dose roxithromycin on stable bronchiectasis]

OBJECTIVE

To investigate the impact of treatment with low dose roxithromycin on clinical symptoms and CT scores in patients with stable bronchiectasis.

METHODS

Fifty patients with bronchiectasis in stable condition were randomly assigned to a control group and a treatment group. Patients in the control group received ambroxol hydrochloride tablet 90 mg 3 times a day. Patients in the treatment group received roxithromycin disperse tablet 0.15 g every day and ambroxol hydrochloride tablet 90 mg 3 times a day. The course of treatment lasted for 6 months. Quality of life was assessed using St. George's respiratory questionnaire (SGRQ). The British Medical Research Council (MRC) dyspnea scale was used to assess the degree of dyspnea. The score for CT evaluation of the thorax, quality of life and SGRQ were performed for all patients before and after the treatment.

RESULTS

After 6 months, the scores for quality of life (48 ± 13) were lower compared to that (58 ± 15) before treatment in the control group; however, the scores for bronchial wall thickening of bronchiectasis (1.8 ± 0.5) were higher than that (1.8 ± 0.4) before study. The scores for the extent of bronchiectasis (2.7 ± 1.6), the bronchial wall thickening of bronchiectasis (1.3 ± 0.4) and the global CT score (6.7 ± 2.5) were reduced after treatment as compared to those before treatment [(4.8 ± 2.3), (1.8 ± 0.5), (9.5 ± 3.3)] in the treatment group, (all P < 0.01). The degree of dyspnea (1.3 ± 0.4) and quality of life (42 ± 12) were lower than those before treatment [(1.89 ± 0.45), (56 ± 15)] in the treatment group. Furthermore, the scores for extent of bronchiectasis (2.7 ± 1.6), the scores for the bronchial wall thickening of bronchiectasis (1.3 ± 0.4) and the global CT score (6.7 ± 2.5) in the treatment group were significantly improved as compared with those [(4.8 ± 2.0), (1.8 ± 0.5), (9.7 ± 3.6)] in the control group respectively after treatment. At the same time, the degree of dyspnea (1.3 ± 0.4) in the treatment group was significantly improved as compared with that (1.7 ± 0.4) in the control group after treatment.

CONCLUSIONS

The scores for the bronchial wall thickening of bronchiectasis were increased in patients with stable bronchiectasis. Low dose roxithromycin combined with ambroxol hydrochloride significantly improved degree of dyspnea, reduced scores for extent of bronchiectasis, scores for the bronchial wall thickening of bronchiectasis and the global CT score as compared to treatment with ambroxol hydrochloride alone in patients with bronchiectasis in stable condition.

[Pharmacokinetics and relative bioavailability study of roxithromycin tablet in Chinese healthy volunteers by LC-MS/MS]

This is a study of assessing the comparative bioavailability of roxithromycin produced by two companies in 36 healthy volunteers. On the basis of informed consent, 36 healthy male volunteers received each medicine at the roxithromycin dose of 150mg in a cross-over study. There was a 1-week washout period among the doses. Plasma concentrations of roxithromycin were monitored by an LC-MS/MS for over a period of 72 hours after administration. In this study, roxithromycin was generally well tolerated. After an oral administration of roxithromycin capsule, the pharmacokinetic parameters of roxithromycin, such as AUC(0-72 h) (66 076 microg x L x h(-1) and 70 334 microg x L x h(-1) for test and reference capsule, respectively) and AUC(0-infinity) (68 153 microg x L x h(-1) and 72 362 microg x L x h(-1)) were significantly similar. For test and reference capsule, the values of C(max) were 6 631.5 microg x L(-1) and 7 033.9 microg x L(-1) respectively, of T1/2 were 15.39 +/- 4.61 h and 16.06 +/- 5.56 h, and of T(max) were 1.3 +/- 0.9 h and 1.4 +/- 0.7 h respectively. The relative bioavailability F was 94.9% +/- 22.4% of tested formulation. The values of 90% confidence interval around the ratios (test/reference) (obtained by analysis of variance, ANOVA) were 88.3%-101.2% for C(max), 86.2%-98.9% for AUC(0-72) h, being within the predefined acceptable range for the conclusion of bioequivalence. The results of statistical analysis suggest that the two formulations be bioequivalent.

[An empirical study of treating chronic sinusitis with low dose Roxithromycin]

OBJECTIVE

Observe the therapeutic effect of low dose Roxithromycin in treating chronic sinusitis and further discuss the mechanism of Roxithromycin facile endothelial cell apoptosis.

METHOD

All 47 patients who suffer chronic sinusitis at out-patient clinic from 2006. 10 to 2008. 03 were administered low dose Roxithromycin. Follow up all the patients and get polypi at 3-month and 6-month. AO/EB was employed to detect the apoptosis of endothelial cell.

RESULT

At 3-month and 6-month the improvement of ventilation are 37.25 +/- 12.21, 63.15 +/- 22.78; Decrease of nasal discharge are 42.12 +/- 13.56, 74.45 +/- 28.79; alleviation of headache are 18.98 +/- 7. 66, 34.47 +/- 14.11; Improvement of olfactory are 21.23 +/- 8.41, 38.18 +/- 16.54; Apoptotic index are (39.54 +/- 6.86)% and (62.34 +/- 8.67)%, which are significantly different (P<0.05).

CONCLUSION

Low dose Roxithromycin has good long term curative effect in treating chronic sinusitis. Low dose Roxithromycin can greatly urge the apoptosis of endothelial cell.

Can long-term antibiotic treatment prevent progression of peripheral arterial occlusive disease? A large, randomized, double-blinded, placebo-controlled trial

PURPOSE

The purpose was to investigate in a large, randomized, double-blinded, placebo-controlled trial, whether antibiotic treatment can prevent progression of peripheral arterial disease (PAD).

MATERIAL AND METHODS

Five hundred and seven patients were included; all patients had an established diagnosis of PAD. Their mean age was 66 years (36-85), and 59% were males. Patients were randomized to Roxithromycin 300 mg daily for 28 days. Baseline investigations were ankle blood pressure, ankle-brachial blood pressure index (ABPI), walking distance, C. pneumoniae serology, cholesterol and medical history. Follow-up was performed every 6 months. Primary events were defined as death, peripheral revascularization and major lower limb amputation. Secondary events were thrombosis, stroke, transient cerebral ischaemic attack and myocardial infarction. Change in ABPI was also investigated. Data were analyzed mainly by Cox regression and linear regression.

RESULTS

Included patients with PAD were randomized. Two patients withdrew. Of the remaining, 248 received roxithromycin and 257 placebo. In the treatment group 55% were seropositive and 53% in the placebo group. Mean follow-up was 2.1 years (range 0.06-5.1 years). In the placebo group, 26 died and 80 primary events occurred in total. In the treatment group, 28 died and 74 primary events were observed. The hazard ratio of death was 1.13 (95% CI: 0.68; 1.90), and of primary events 0.92 (95% CI: 0.67; 1.26). Also on secondary events and ABPI changes, no significant differences were found.

CONCLUSION

Long-term treatment with roxithromycin is ineffective in preventing death, amputation, peripheral revascularization, myocardial infarction, stroke, transient cerebral ischaemic attack, thrombosis and decline in ABPI in patients with an established diagnosis of PAD.

Mechanisms of venoocclusive disease resulting from the combination of cyclophosphamide and roxithromycin

BACKGROUND

High doses (>or=500 mg/m) of cyclophosphamide are known to cause venoocclusive disease (VOD). The authors recently observed a patient treated with immunosuppressive cyclophosphamide doses (100 mg/day) and roxithromycin who developed VOD. Because roxithromycin inhibits cytochrome P450 (CYP) 3A4 and P-glycoprotein, the patient may have been exposed to higher cyclophosphamide and/or cyclophosphamide metabolite concentrations.

METHODS

The effect of roxithromycin on the metabolism and toxicity of cyclophosphamide was studied using human hepatic microsomes and a human endothelial cell line.

RESULTS

Cyclophosphamide or roxithromycin at concentrations from 0.05 to 500 micromol/L were not toxic to endothelial cells as assessed by lactate dehydrogenase (LDH) leakage assay. However, the combination of roxithromycin (500 micromol/L) and cyclophosphamide was toxic for all the tested cyclophosphamide concentrations (0.05 to 500 micromol/L) without clear concentration dependence (LDH ratio 38.3 +/- 11.0 [mean +/- SEM] for the combination with cyclophosphamide 0.05 micromol/L and 50.2 +/- 10.2 for the combination with cyclophosphamide 500 micromol/L; P <or= 0.005 for all tested combinations vs. control). Although roxithromycin did not favor the generation of toxic metabolites from cyclophosphamide, it led to cyclophosphamide accumulation due to inhibition of both CYP3A4 and CYP2B6. Although roxithromycin inhibited P-glycoprotein, this was not the mechanism by which cyclophosphamide toxicity was increased because cyclophosphamide in combination with other P-glycoprotein inhibitors was not toxic to endothelial cells. In the presence of roxithromycin (500 micromol/L), cyclophosphamide (500 micromol/L) induced apoptosis in endothelial cells (34.3 +/- 10.4% apoptotic cells [in % of total cells] for the combination of cyclophosphamide and roxithromycin, 0.7 +/- 0.25% for cyclophosphamide alone, 0% for roxithromycin alone; P < 0.0001) most probably by mitochondrial membrane permeability transition and release of cytochrome c.

CONCLUSIONS

The combination cyclophosphamide and roxithromycin, but not the individual compounds, is toxic to endothelial cells by inducing apoptosis. Inhibition of P-glycoprotein and formation of toxic metabolites are unlikely causes.

Long-term Antibiotic Treatment with Roxithromycin in Patients with Multiple Sclerosis

BACKGROUND

There are conflicting results concerning an association between Chlamydia pneumoniae and MS (multiple sclerosis). In the present study, we investigated a possible therapeutic option with antibiotics.

PATIENTS AND METHODS

In our randomized, placebo-controlled double-blind study, 28 patients with the confirmed diagnosis of MS [61% relapsing-remitting MS (RR-MS), 32% secondary chronic-progressive MS (SP-MS) and 7% primary chronic progressive MS (PP-MS)] were treated over a time period of 12 months with three cycles of a 6-week oral antibiotic therapy with roxithromycin (300 mg per day) or placebo.

RESULTS

No significant differences were observed in patients with RR-MS regarding the expanded disability status scale (EDSS) and the relapse rate when comparing treatment with roxithromycin and placebo.

CONCLUSION

Our study shows that the patients with MS do not profit from a long-term antibiotic treatment with roxithromycin compared to placebo treatment. A causative connection between bacterial infections with C. pneumonia and MS therefore does seem very unlikely.

Preparation of roxithromycin-polymeric microspheres by the emulsion solvent diffusion method for taste masking

Microspheres of roxithromycin with Eudragit S100 and silica were prepared by the emulsion solvent diffusion method to mask the bitter taste of the antibiotic. The effect of different polymers and drug-polymer ratios on the taste masking and the characteristics of the microspheres were investigated. It was found that Eudragit S100 was the best for masking the unpleasant taste of roxithromycin among the six kinds of polymers investigated. The results of DSC, X-ray diffraction and IR showed that there were several combinations of roxithromycin and Eudragit S100. The influence of other formulation factors, i.e. dichloromethane-acetone ratios and silica-polymer ratios on the properties of the microspheres were also examined. In conclusion, the results of the present study will be helpful for the preparation of oral forms of roxithromycin with an acceptable taste.

Impact of pharmaceutical dosage forms on the pharmacokinetics of roxithromycin in healthy human volunteers

OBJECTIVES

The impact of two different pharmaceutical preparations on the pharmacokinetics of roxithromycin was investigated in healthy human volunteers.

METHODS

The degradation kinetics and products of roxithromycin were investigated in simulated gastric fluid and simulated intestinal fluid. Two oral dosage forms of roxithromycin were employed: enteric-coated pellets and dispersible tablets.

RESULTS

The degradation half-time of roxithromycin in simulated gastric fluid was 0.23 h, and three main degradation products were characterized. In contrast, roxithromycin was stable in simulated intestinal fluid and remained unchanged after a 1.00 h incubation. The roxithromycin enteric-coated pellets exhibited higher bioavailability and a more potent serum antibacterial activity than the dispersible tablets.

CONCLUSIONS

The type of oral dosage forms of roxithromycin altered its pharmacokinetics. Whether or not this affects the in vivo antibacterial efficacy requires further study.

Progression of peripheral arterial occlusive disease is associated with Chlamydia pneumoniae seropositivity and can be inhibited by antibiotic treatment

A possible influence of Chlamydia pneumoniae seropositivity on the clinical course of peripheral arterial occlusive disease (PAOD) has not been investigated previously. Though roxithromycin therapy was found to inhibit progression of PAOD, the nature of this effect (antibiotic or anti-inflammatory) has remained elusive. The course of PAOD was prospectively assessed in elderly men during 4 years, comparing 51 C. pneumoniae seropositive (IgG>/=1:128) with 46 seronegative patients (IgG<1:64 and IgA<1:32). Twenty of the seropositive patients were treated with roxithromycin (400 mg daily) for 4 weeks. Limitation of the walking distance to 200 m or less was observed in 55% of the seropositive untreated patients as compared to 30% of both, seronegative and macrolide-treated patients. The number of invasive revascularizations per patient was 1.7 in the seropositive untreated group as compared to 0.5 in the seronegative and the macrolide-treated group. Considering possible confounding variables, such as classical vascular risk factors, ordinal regression analyses showed a significant association of C. pneumoniae seropositivity with limitation of the walking distance (p=0.027) and need for invasive revascularization (p=0.037). The effect of macrolide treatment on these outcome measures was marked (p<0.001 and p=0.040, respectively) during 2.7 years but decreased in the second part of the observation period. This study provides good evidence that C. pneumoniae are involved in the progression of PAOD and that antibiotic treatment directed against C. pneumoniae is effective in inhibiting this process.

Antibody levels against Chlamydia pneumoniae and outcome of roxithromycin therapy in patients with acute myocardial infarction. Results from a sub-study of the randomised Antibiotic Therapy in Acute Myocardial Infarction (ANTIBIO) trial

BACKGROUND

Results of studies concerning prevention of cardiovascular disease by treatment with macrolide antibiotics targeting C. pneumoniae infection are still controversial. This study describes the results of different tests for infection with C. pneumoniae as well as the effect of treatment with roxithromycin in patients with acute myocardial infarction (AMI) in relation to their serostatus against C. pneumoniae.

METHODS

We analysed blood of 160 patients who came from the ANTIBIOtic therapy after an AMI ( ANTIBIO-) study, a prospective, randomised, placebo-controlled, double-blind study to investigate the effect of roxithromycin 300 mg/OD for 6 weeks in patients with an AMI. Anti- Chlamydia IgG-, IgA-, and IgM-antibodies of these patients were analysed by means of different test systems.

RESULTS

There was a good correlation between the two IgG and IgA methods (r = 0.900, p < 0.001 and r = 0.878, p < 0.001, respectively), but marked differences in the prevalence of positive tests. This resulted in only moderate concordance values, as expressed by the Kappa coefficients, for IgG kappa = 0.611 (95% CI = 0.498-0.724, p < 0.001) and for IgA kappa = 0.431 (95% CI: 0.322-0.540, p < 0.001). No significant association between positive C. pneumonia titers and the combined clinical endpoint during the 12 month follow-up could be found. In all test systems used, patients with positive anti- C. pneumoniae titers did not benefit from roxithromycin therapy (p = ns).

CONCLUSION

Depending on the test system used, there are large differences in the prevalence of anti- C. pneumoniae seropositive patients. Clinical events during the 12 month follow-up after AMI did not depend on serostatus against C. pneumoniae and treatment with roxithromycin did not influence these events, independently of the serostatus against C. pneumoniae. However, the power of this subgroup analysis was low to detect small but significant differences.

Excretion of electrolytes in Brown Norway and Fischer 344 rats: effects of adrenalectomy and of mineralocorticoid and glucocorticoid receptor ligands

Our previous studies showed that adrenalectomy (ADX) has surprisingly no effect on body weight and fluid intake in the Brown Norway rat strain, suggesting that mineralocorticoid receptor (MR)-mediated effects are present even in absence of corticosteroids in this strain. Moreover, glucocorticoid receptor (GR)-mediated mechanisms are more effective in Brown Norway than in Fischer 344 rats. Such functional differences in corticosteroid receptor pathways between Brown Norway and Fischer 344 rats led us to compare the effect of ADX and MR/GR-mediated actions on sodium and potassium excretion between these two rat strains. To this end, we first measured the effect of an acute high dose of aldosterone on the urinary Na+/K+ concentration ratio in intact and ADX Brown Norway and Fischer 344 rats. Second, to discriminate mineralocorticoid from glucocorticoid actions, we treated chronically ADX rats with increasing doses of aldosterone or RU28362, a pure GR agonist, in the drinking fluid. As sodium homeostasis involves salt appetite regulation, behaviour under mineralocorticoid control, we also measured saline preference in Brown Norway and Fischer 344 rats. Our data illustrate: (1) the very limited effect of ADX on body weight, food and fluid intake, diuresis, natriuresis, kaliuresis and salt appetite in Brown Norway rats, supporting the presence of MR signalling pathways in the absence of adrenal steroids in these rats; (2) the insensitivity of MR to aldosterone in intact Brown Norway rats, and the reduced sensitivity of MR to aldosterone in ADX Brown Norway rats compared with ADX Fischer 344 rats; and (3) the greater sensitivity of GR-related mechanisms to RU28362 in Brown Norway than in Fischer 344 rats in terms of body weight gain and electrolyte excretion. Considering that both MRs and GRs regulate hypothalamic-pituitary-adrenal axis processes, such functional differences in corticosteroid receptors could be at the origin, at least partly, of the strain differences in corticotropic activity/reactivity to stress previously described.

Effect of a short antibiotic treatment with roxithromycin on circulating adhesion molecules after coronary stenting: a single-center pilot trial

BACKGROUND

The aim of this study was to assess the effect of periprocedural antibiotic treatment with roxithromycin on circulating cell adhesion molecules and restenosis after coronary stent implantation.

METHODS

Case-control study enrolling 25 consecutive patients submitted to coronary stenting for stable, single-vessel coronary artery disease, treated with 300 mg roxithromycin once daily for 5 days, starting 2 days before the procedure (group R). Twenty-five patients, matched for lesion site, length and diameter, as control group (group C). The serological status for Chlamydia pneumoniae (CP) infection (IgG, ELISA) was assessed in all patients. The plasma concentrations of soluble intercellular adhesion molecule-1 (sICAM-1), E-selectin and C-reactive protein at 1 month after coronary stenting were compared with baseline values. Binary restenosis (> or = 50%) was also evaluated at 6 months.

RESULTS

sICAM-1 significantly decreased at 1 month in group R vs group C (371 +/- 181 vs 573 +/- 273 ng/ml, p = 0.005). This decrease was more evident in patients with a positive serology for CP (CP+) (group R 373 +/- 131 vs group C 597 +/- 255 ng/ml, p = 0.014). Antibiotic treatment had no effects on circulating E-selectin levels at 1 month (56.7 +/- 97 vs 49.8 +/- 62 ng/ml, p = 0.54). The restenosis rate (9/50, 18%) was similar in the two groups (group R 5/25 [20%], group C 4/25 [16%]). The restenosis rate was similar in the CP+ vs CP- group (6/35 [17%] vs 3/15 [20%]).

CONCLUSIONS

A short course of treatment with roxithromycin at the time of coronary stenting induces a significant reduction in the sICAM-1 levels at 1 month but apparently does not influence the restenosis rate.

A case of cellulitis complicating Campylobacter jejuni subspecies jejuni bacteremia and review of the literature

Infection with Campylobacter species is a predominant cause of food-borne gastroenteritis in the industrialized world. Bacteremia is detected in <1% of patients with diarrhea, mainly in immunocompromised hosts or those in the extremes of age. Reported here is the case of a 78-year-old, immunocompromised male patient with Campylobacter jejuni subsp. jejuni bacteremia complicated by cellulitis. The infection was characterized by a protracted course with several recurrences and refractoriness to multiple antibiotic regimens, responding only to a prolonged course of meropenem treatment. The frequency of cellulitis as reflected in previously reported series of Campylobacter bacteremia and the clinical characteristics of this difficult-to-treat infection are reviewed.

Clinical evaluation of roxithromycin: a double-blind, placebo-controlled and crossover trial in patients with acne vulgaris

We clinically evaluated roxithromycin (ROM) in a double blind, placebo-controlled, and crossover trial in patients with inflammatory acne. Patients with inflammatory acne who were attending our outpatient clinic for treatment and who had not received topical or systemic treatment for the previous month were enrolled in this study. Patients were randomly separated into two groups. Group I consisted of 26 patients. The patients received 2x150 mg/day ROM orally in the first period and 2x1 placebo tablets/day in the second period. Group II consisted of 20 patients. These patients received 2x1 placebo tablets/day in the first period and 2x150 mg/day ROM orally in the second period. The first period was the first four weeks, and then there was a washout period of two weeks (5th and 6th). The second period was the next four weeks (7th to 10th weeks) after the washout period. Median acne scores had clearly decreased in both groups at the end of the study. Differences of median acne scores were statistically significant in both groups between at baseline and at the end of the study (p<0.001). The results showed that ROM is a safe and effective alternative in the treatment of inflammatory acne with few side effects and good compliance.

Suppressive activity of macrolide antibiotics on nitric oxide production from nasal polyp fibroblasts in vitro

The influence of macrolide antibiotics on nitric oxide (NO) generation was examined using human nasal polyp fibroblasts (NPFs) in vitro. Addition of roxithromycin (RXM) at a concentration of > 7.5 microg/ml to cell cultures was shown to suppress NO production in response to stimulation with 25.0 ng/ml tumor necrosis factor (TNF)-alpha. However, jyosamycin (JM) did not suppress NO production from NPFs induced by TNF-alpha stimulation in vitro, even when added to cell cultures at a concentration of 20.0 microg/ml. We then examined the influence of RXM on inducible nitric oxide synthase (iNOS) mRNA expression in NPFs. Addition of RXM at a dose of 7.5 microg/ml to cell cultures caused reduction of iNOS mRNA expression, which was enhanced by TNF-alpha stimulation in vitro.

[Metabolism of roxithromycin in dogs]

AIM

To investigate the metabolic profile of roxithromycin in dogs and the effects of oral and intravenous administrations on the metabolism of roxithromycin.

METHODS

Liquid chromatography-tandem mass spectrometry (LC-MSn) was used for separation and analysis of roxithromycin and its metabolites in dog bile after an oral dose or intravenous dose of roxithromycin. The metabolites were identified by comparisons of their mass spectra and LC behaviors with the references.

RESULTS

Totally 13 metabolites were detected in dog bile, including N-demethylated derivatives, N, N-didemethylated derivatives, O-dealkylether derivatives, decladinose derivatives, and the geometric isomers of parent drug and its metabolites.

CONCLUSION

Roxithromycin underwent 4 metabolic pathways in which geometric isomerization and decladinose metabolism were found to be markedly different between the two administration routes.

Determination of roxithromycin by liquid chromatography/mass spectrometry after multiple-dose oral administration in broilers

A highly sensitive and specific method for the determination of roxithromycin in broiler tissues by LC/MS was developed and validated. A dichloromethane extract of the sample was separated on C18 reversed-phase column with acetonitrile-50 mM ammonium acetate (80:20, v/v) as the mobile phase and analyzed by LC/MS via atmospheric pressure ionization/electrospray ionization interface. The limit of detection and limit of quantitation were 1 ng/g and 5 ng/g. The method has been successfully applied to determine for roxithromycin in various tissues of broilers. Residue concentrations were associated with administered dose. At the termination of treatment, roxithromycin was found in all collected samples for both dose groups. Liver was detected to have the highest residual concentration of roxithromycin. Residue concentrations of roxithromycin were lower than its LOQ in all tissues from both dose groups 10 days after the treatment of roxithromycin mixed with drinking water at a dose rate of 15 mg/L or 60 mg/L to each broiler for 7 days.

Roxithromycin treatment of scrub typhus (tsutsugamushi disease) in children

BACKGROUND

Although chloramphenicol and doxycycline have been used for the treatment of scrub typhus, a difficulty exists in determining which drug to use in treating children because of such potential complications as aplastic anemia or tooth discoloration. We evaluated the effect of roxithromycin, a macrolide antibiotic, on scrub typhus in children.

METHODS

A retrospective analysis was conducted on 39 children with scrub typhus who were treated with doxycycline (DC), chloramphenicol (CM) or roxithromycin (RM) between 1991 and 2000. We divided the patients into the DC-treated group (DC group; 16 children), CM-treated group (CM group; 14 children) and RM- treated group (RM group; 9 children) and compared these groups.

RESULTS

Most cases (97%) occurred in October and November. Fever and rash were observed in all 39 cases, and an eschar was noted in 36 cases (92%). No statistical differences could be found between the 3 groups in mean age, duration of fever before admission, white blood cell (WBC) count and complications including abnormal liver enzymes. In most cases defervescence after treatment was within 24 h (34 cases, 87%) and during 24 to 48 h in 2 cases in the DC group, 1 case in the CM group and 2 cases in the RM group (no statistical difference).

CONCLUSION

Roxithromycin was as effective as conventional doxycycline or chloramphenicol in children with scrub typhus and may be safer to use.

Inhibitory effects of 14-membered ring macrolide antibiotics on bleomycin-induced acute lung injury

14-membered ring macrolides have been reported to have anti-inflammatory effects and to decrease neutrophil infiltration into the airways in chronic lower respiratory tract diseases. This study investigated the potential inhibitory effects of macrolide antibiotics on bleomycin-induced acute lung injury. Four drugs were studied: two 14-membered ring macrolides, clarithromycin (CAM) and roxithromycin (RXM); a 15-membered ring macrolide, azithromycin (AZM); and a 16-membered ring macrolide, josamycin (JM). Their effects were compared with macrolide untreated, pretreated, and post-treated groups. An acute lung injury was inhibited by pretreatment with CAM or RXM, which significantly ameliorated the bleomycin-induced increases in the total cell and neutrophil counts in bronchoalveolar lavage (BAL) fluids and the wet lung weight. The pretreatment with CAM or RXM also suppressed inflammatory cell infiltration and interstitial lung edema in the histopathological study. These inhibitory effects were associated with a decreased KC concentration in the BAL fluid and a decreased number of apoptotic cells in the lungs. Posttreatment with CAM or RXM had no marked inhibitory effects. Pretreatment with AZM was much less effective, and JM showed no inhibitory effects. These findings suggest that 14-membered ring macrolides have different effects on inflammatory lung disease than 15- and 16-membered ring macrolides and may be therapeutic agents for acute lung injury and pulmonary fibrosis.

Quantitative comparison of the cytocidal effect of seven macrolide antibiotics on human periodontal ligament fibroblasts

The cytocidal effect of seven macrolide antibiotics on human periodontal ligament fibroblasts (Pel cells) was studied. Pel cells were exposed for 48 h to erythromycin (EM), clarithromycin (CAM), roxithromycin (RXM), azithromycin (AZM), josamycin (JM), midecamycin (MDM), and rokitamycin (RKM), and allowed to form colonies. The cytocidal effect of the macrolides was measured as a decrease in colony-forming efficiency and was found to increase with the concentration. To obtain a quantitative measure of the cytocidal effect, the LD50, i.e. the concentration that decreases colony-forming efficiency 50% relative to control cells, was extrapolated from the concentration-response curves. The rank of the macrolides according to their cytocidal effect (LD50) was RKM > RXM > CAM > AZM > JM > MDM approximately EM. RKM, RXM, CAM, AZM, and JM were at least 1.7-12.2 times more cytocidal than MDM or EM. When extrapolated from the concentration-response curves, the relative survival of the Pel cells exposed to each of the macrolides at the MIC90 concentrations for periodontopathic bacteria was estimated to be: > or = 53.8% for RKM, > or = 92.7% for RXM, > or = 94.6% for CAM, > or = 97.1% for AZM, and > or = 86.2% for EM. The effect of the antibiotics on the mRNA expression of alkaline phosphatase (ALP) and type I procollagen (COL) was examined in Pel cells exposed for 48 h to RXM, CAM, AZM, and EM, which exhibited strong, moderate, and weak cytocidal activity. The constitutive levels of both ALP and COL mRNA were retained in cells exposed to RXM at < or = 3 microM, CAM at < or = 10 microM, and AZM or EM at < or = 3 microM. The MIC90 against periodontopathic bacteria is < or = 4.8 microM for RXM, 5.3 microM for CAM, 2.7 microM for AZM, and 21.8 microM for EM. These results suggest that topical administration of CAM or AZM to the gingival crevice at their MIC90 concentration for periodontopathic bacteria would have little adverse effect on the growth and differentiation of the periodontal ligament. It is important to note, however, that these findings have yet to be extrapolated to in vivo conditions.

Randomized double-blind controlled trial of roxithromycin for prevention of abdominal aortic aneurysm expansion

BACKGROUND

Macrolide treatment has been reported to lower the risk of recurrent ischaemic heart disease. The influence of macrolides on the expansion rate of abdominal aortic aneurysms (AAAs) remains unknown. The aim was to investigate the effect of roxithromycin on the expansion rate of small AAAs.

METHODS

A total of 92 subjects with a small AAA were recruited from two populations. One population consisted of 6339 men aged 65-73 years who were offered a hospital-based mass screening programme for AAA. From this population 66 subjects were recruited. The remaining 26 men were recruited from among 49 subjects diagnosed at interval screening for an initial aortic diameter between 25 and 29 mm. Subjects were randomized to receive either oral roxithromycin 300 mg once daily for 28 days or matching placebo, and followed for a mean of 1.5 years.

RESULTS

During the first year the mean annual expansion rate of AAAs was reduced by 44 [corrected] per cent in the intervention group (1.56 mm per year), compared with 2.80 mm per year following placebo (P = 0.02). During the second year the difference was only 5 per cent [corrected]. Multiple linear regression analysis showed that roxithromycin treatment and initial AAA size were significantly related to AAA expansion when adjusted for smoking, diastolic blood pressure and immunoglobulin A level of 20 or more [corrected]. Logistic regression analysis confirmed a significant difference in expansion rates above 2 mm annually between the intervention and placebo groups: odds ratio = 0.09 (95 per cent confidence interval 0.01-0.83) [corrected].

CONCLUSION

In comparison to placebo, roxithromycin 300 mg daily for 4 weeks reduced the expansion rate of AAAs.

Improvement in right lung atelectasis (middle lobe syndrome) following administration of low-dose roxithromycin

Middle lobe syndrome is a distinct clinical entity characterized by right middle lobe atelectasis. Prompt diagnosis and initiation of medical therapy including the administration of antibiotics and the avoidance of irritating agents may be effective. However, abnormal shadows on chest radiography remain unchanged even when acute symptoms have disappeared, suggesting latent lesional inflammation or recurrence. We describe 2 cases of atelectasis in the middle lobe of the right lung which resolved completely after administration of low-dose roxithromycin. Thus, low-dose therapy with a macrolide could be of interest or some value in these cases, but it is too early to draw a definite conclusion.

Postantibiotic effects and postantibiotic sub-MIC effects of erythromycin, roxithromycin, tilmicosin, and tylosin on Pasteurella multocida

When intermittent dosing is used during treatment, the concentrations of antibiotics fluctuate and subinhibitory concentrations may occur between doses. Postantibiotic effects (PAEs) and postantibiotic subinhibitory effects (PA SMEs) on bacteria may provide additional, valuable information for the rational use of a drug in clinical practice. In this study tilmicosin was the most active antibiotic tested against P. multocida type D with MICs ranging from 4-16 mg/l. Roxithromycin and tilmicosin induced a statistically significantly longer PAE than did tylosin against P. multocida types A and D (P < 0.05). The duration of PAEs and PA SMEs were proportional to the concentrations of drugs used for exposure. The PA SMEs were substantially longer than PAEs on P. multocida. Tilmicosin had a longer PA SME compared with erythromycin, roxithromycin and tylosin for P. multocida. The computerized incubator used in the present study provided an efficient and convenient determination of PAE and PA SME, allowing frequent measurements of the bacterial growth.

Diffuse panbronchiolitis observed in a white man in Turkey

Diffuse panbronchiolitis (DPB) is a distinct clinicopathological entity which is characterized by chronic recurrent sinopulmonary infection and inflammation. It is prevalent in the Far East, but extremely rare in western countries. In this report, we described the first Turkish case of DPB and also evaluated demographic and diagnostic characteristics of 18 patients with DPB, previously reported from non-Asian countries. We believe that DPB patients described from these countries may also increase if this disease is taken into consideration in differential diagnosis of sinopulmonary diseases. Another consideration is that, since the treatment and prognosis of DPB are different from other obstructive pulmonary diseases, it should not be mistaken for others.

Optimization study on the formulation of roxithromycin dispersible tablet using experimental design

This study set out to improve the physical and pharmaceutical characteristics of the present formulation using an appropriate experimental design. The work described here concerns the formulation of the dispersible tablet applying direct compression method containing roxithromycin in the form of coated granules. In this study 2(3) factorial design was used as screening test model and Central Composite Design (CCC) associated with response surface methodology was used as optimization study model to develop and to optimize the proper formulation of roxithromycin dispersible tablet. The three independent variables investigated were functional excipients like binder (X1), disintegrant (X2) and lubricant (X3). The effects of these variables were investigated on the following responses: hardness (Y1), friability (Y2) and disintegration time (Y3) of tablet. Three replicates at the center levels of the each design were used to independently calculate the experimental error and to detect any curvature in the response surface. This enabled the best formulations to be selected objectively. The effect order of each term to all response variable was X3> X2> X1> X1*X2> X2*X2> X2*X3> X3*X3> X1*X3> X1*X1 and model equations on each response variables were generated. Optimized compositions of formula were accordingly computed using those model equations and confirmed by following demonstration study. As a result, this study has demonstrated the efficiency and effectiveness of using a systematic formulation optimization process to develop the tablet formulation of roxithromycin dispersible tablet with limited experiment.

Comparative pharmacodynamic analysis of Q-T interval prolongation induced by the macrolides clarithromycin, roxithromycin, and azithromycin in rats

In order to evaluate the arrhythmogenic potency of macrolide antibiotics in a quantitative manner, we analyzed the influence of clarithromycin (CAM), roxithromycin (RXM), and azithromycin (AZM) on Q-T intervals from pharmacokinetic and pharmacodynamic points of view and in comparison with the potency of erythromycin (EM) previously reported by us for rats. Male Sprague-Dawley rats were anesthetized, and CAM (6.6, 21.6, and 43.2 mg/kg of body weight/h), RXM (20 and 40 mg/kg/h), and AZM (40 and 100 mg/kg/h) were intravenously injected for 90 min to obtain the time courses of drug concentrations in plasma and the changes in the Q-T intervals during and after the drug injections. Distinct Q-T interval prolongation of up to 10 ms was observed with CAM at its clinical concentrations. RXM and AZM evoked Q-T interval prolongation at concentrations higher than their clinical ranges. The potencies for Q-T interval prolongation, assessed as the slope of the concentration-response relationship, were 6.09, 0.536, and 0.989 ms. ml/microg for CAM, RXM, and AZM, respectively. There was hysteresis between the change in the Q-T intervals and the time course of the plasma concentration of each drug. The rank order of clinical arrhythmogenicity was estimated to be EM > CAM > RXM > AZM, as assessed from the present results and our previous report for EM. In conclusion, RXM and AZM were estimated to be less potent at provoking arrhythmia than EM and CAM. These results should be useful for making a safer choice of an appropriate agent for patients with electrocardiographic risk factors.

An open trial of oral macrolide treatment for psoriasis vulgaris

Seventeen patients were included in a clinical open trial of macrolides for treatment of psoriasis vulgaris. PASI scores, itch and ointment scores were used to evaluate their effectiveness. PASI scores dropped from 22.8 to 13.7; this was statistically significant. Itch reduced in 11 out of 13 patients, and the extent of itch reduced significantly by 54% on average. Ointment scores reduced from 44.9 to 34.4, which was also statistically significant. Macrolides are known not only as potent anti-biotics, but also as immunomodulatory agents. These data suggest that macrolides could be used as one of the adjunctive therapies of psoriasis vulgaris, and this study is a first step toward the future evaluation of macrolides in a double blind trial.

[Role of macrolides in antibacterial therapy of otitis media in children]

A new macrolide vilprafen (jozamicine) was used as monotherapy or in combination with rhinopront and mucopront in 50 children with inflammation in the middle ear. Otorrhea ceased in 41 patients. Vilprafen is recommended after failure of penicilline or cephalosporine treatment, in allergic reaction to these antibiotics, in simultaneous adenoiditis and exacerbation of chronic tonsillitis.

Two weeks triple therapy with lansoprazole, amoxycillin and roxythromycin is better than dual therapy with lansoprazole and amoxycillin for H. pylori infection: a randomised, clinical trial

AIMS

To compare the efficacy of 2 weeks of dual therapy of Lansoprazole and Amoxycilline with triple therapy of Lansoprazole, Amoxycilline and Roxythromycin for H. pylori eradication.

SUBJECTS

Twenty-five suffering from dyspepsia and found H. pylori positive (CLO) during upper GI endoscopy.

METHODS

Patients were divided into 2 groups, one group received Lansoprazole (30 mg) once a day, and amoxycilline (500 mg) three times a day (group I), while the second group received Lansoparazole and amoxycillin in similar dosage with the addition of Roxythromycin (150 mg) twice a day (group II). H. pylori status was confirmed on endoscopy using CLO test at entry to the protocol and then at 4 weeks.

RESULTS

H. pylori eradication was 57% in group I and 86% in group II with healing of lesions in all cases.

CONCLUSION

Better response with triple therapy (group II) indicates enhanced eradication of the pathogens with triple therapy while using roxythromycin (JPMA 50:157, 2000).

Prognostic factors of chronic rhinosinusitis under long-term low-dose macrolide therapy

We studied the immunological and histopathological factors that affect the prognosis of chronic rhinosinusitis under long-term low-dose macrolide therapy. Sixteen patients with chronic rhinosinusitis were given 200 mg clarithromycin or 150 mg roxithromycin orally once a day without other concurrent treatments for 2-3 months. Measurement of the serum IgE level, blood cell count and differential leukocyte count of the peripheral blood, cytological assessment of the nasal smear and computed tomographic (CT) scans of the paranasal sinuses were performed before treatment. The opacity of the sinuses was estimated and scored by the CT images. After treatment, anterior ethmoidal mucosa samples were collected, an infiltrated inflammatory cells, interferon (IFN)-gamma-positive cells and interleukin (IL)-4-positive cells were examined histologically and immunohistochemically. The severity of nasal symptoms was scored before and after treatment, and the improvement rate of the score (symptomatic improvement rate) was calculated. Patients with normal levels of serum IgE (</=250 U/ml) showed a significantly higher symptomatic improvement rate than those with high levels of serum IgE (42.1 +/- 11.2 vs. 4.9 +/- 3.1%, p = 0.046). The symptomatic improvement rate was inversely correlated with the eosinophil counts in the peripheral blood (r = -0.51, p = 0.04), in the nasal smear (r = -0.54, p = 0.045) and in the sinus mucosa (r = -0.54, p = 0.02). Meanwhile, the CT score, the number of IFN-gamma-positive cells and IL-4-positive cells in the sinus mucosa and neutrophil counts in the nasal smear and in the sinus mucosa failed to correlate with the symptomatic improvement rate. These results suggest that macrolide therapy is indicated for patients without atopy or smear/tissue/peripheral blood eosinophilia. On the contrary, the severity of the disease, Th1/Th2 dominance in the sinus mucosa and neutrophilia are unlikely to be prognostic factors of chronic rhinosinusitis under long-term low-dose marolide therapy.

Roxithromycin and clarithromycin, 14-membered ring macrolides, potentiate the antitumor activity of cytotoxic agents against mouse B16 melanoma cells

We previously reported antiangiogenic activity of roxithromycin and clarithromycin, 14-membered ring macrolide antibiotics. In the present study, we examined the antitumor effects of roxithromycin and clarithromycin, alone and in combination with several cytotoxic drugs, on mouse B16BL6 melanoma cells in vivo and in vitro. Both roxithromycin and clarithromycin potentiated the inhibition of tumor growth induced by cyclophosphamide, cis-diamminedichloroplatinum(II), Adriamycin and vindesine in vivo. However, neither roxithromycin nor clarithromycin, altered the cytotoxicity of 4-hydroperoxycyclophosphamide, cis-diamminedichloroplatinum(II), Adriamycin or vindesine in an in vitro cell proliferation assay. These results suggest that the antiangiogenic activity of roxithromycin and clarithromycin may provide beneficial effects in combination with cytotoxic therapies against solid tumors.