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PubMed2005

Levofloxacin versus ceftriaxone plus clarithromycin in the treatment of adults with community-acquired pneumonia requiring hospitalization.

Consecutive adult patients admitted to the hospital with community-acquired pneumonia from January 2000 to September 2003 were included in this prospective observational cohort study. A total of 459 patients, 259 treated with levofloxacin in single drug therapy at a dose of 500 mg once a day and 209 with the combination of ceftriaxone plus clarithromycin at a dose of 2 g once a day and 500 mg every 12 h, respectively, were included. The hospital admission decision was made using a clinical guideline based on the Pneumonia Severity Index (PSI). Fifteen (6%) patients died in the group treated with levofloxacin in single drug therapy and 25 (12%) in the group treated with ceftriaxone plus clarithromycin (P = 0.024). The mortality differences between both treatment groups, adjusted by the PSI score, show an OR of 0.39 (95% CI 0.17-0.87). There were no statistically significant differences between the duration of treatments or hospital stay. These data suggest that levofloxacin as single drug therapy is more effective than the combination of ceftriaxone plus clarithromycin in the treatment of moderate to severe pneumonia that requires hospitalization.

Aged↗
PubMed2005

Clarithromycin treatment selects for persistent macrolide-resistant bacteria in throat commensal flora.

The aim of the study was to determine the effect of clarithromycin treatment on resistance development in the commensal throat flora. Alpha-haemolytic streptococci and Neisseria spp. were isolated from patients receiving clarithromycin for eradication of Helicobacter pylori. The treatment resulted in an immediate increase in the number of macrolide-resistant streptococci, which remained for one year after treatment, but declined to background level three years later. The most prevalent resistance gene was mef(A). Neisseria spp. were less affected by the treatment: the number of resistant isolates increased in only in one case during treatment. In conclusion, a one-week standard therapy with clarithromycin selects for an increased prevalence of macrolide-resistant streptococci that persisted for more than one year.

Anti-Bacterial Agents↗
PubMed2005

Heterogeneous susceptibility to metronidazole and clarithromycin of Helicobacter pylori isolates from a single biopsy in adults is confirmed in children.

The aim of this study was to assess the resistance to metronidazole and clarithromycin of individual colonies of Helicobacter pylori from a single biopsy taken from 14 adults and 14 children. The Etest was used to determine the minimum inhibitory concentrations (MICs) of these two antimicrobial drugs for ten individual H. pylori colonies isolated from each initial gastric biopsy culture. We confirmed the heterogeneity in metronidazole and clarithromycin resistance in children as seen in adults before anti-H. pylori treatment. The number of resistant individual colonies ranged from two to nine depending on the subject. All individual colonies from the same biopsy that were resistant to clarithromycin were genetically identical according to randomly amplified polymorphic DNA testing and exhibited the same point mutation according to polymerase chain reaction-restriction fragment length polymorphism.

Adult↗
PubMed2005

Sensitive determination of clarithromycin in human plasma by high-performance liquid chromatography with spectrophotometric detection.

A rapid, selective and sensitive high-performance liquid chromatographic method with spectrophotometric detection was developed for the determination of clarithromycin in human plasma. Liquid-liquid extraction of clarithromycin and norverapamil (as internal standard) from plasma samples was performed with n-hexane/1-butanol (98:2, v/v) in alkaline condition followed by back-extraction into diluted acetic acid. Chromatography was carried out using a CN column (250 mm x 4.6 mm, 5 microm) under isocratic elution with acetonitrile-50 mM aqueous sodium dihydrogen phosphate (32:68, v/v), pH 4.5. Detection was made at 205 nm and analyses were run at a flow-rate of 1.0 ml/min at 40 degrees C. The analysis time was less than 11 min. The method was specific and sensitive with a quantification limit of 31.25 ng/ml and a detection limit of 10 ng/ml in plasma. The mean absolute recovery of clarithromycin from plasma was 95.9%, while the intra- and inter-day coefficient of variation and percent error values of the assay method were all less than 9.5%. Linearity was assessed in the range of 31.25-2000 ng/ml in plasma with a correlation coefficient of greater than 0.999. The method was used to analyze several hundred human plasma samples for bioavailability studies.

Anti-Bacterial Agents↗
PubMed2006

Determination of clarithromycin in human serum by high-performance liquid chromatography after pre-column derivatization with 9-fluorenylmethyl chloroformate: application to a bioequivalence study.

A sensitive liquid chromatographic method for the analysis of clarithromycin, a macrolide antibiotic, in human serum using pre-column derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) is described. The method involved liquid-liquid extraction of the drug and an internal standard (amantadine) followed by pre-column derivatization of the analytes with FMOC-Cl. A mixture of 0.05 M phosphate buffer containing triethylamine (2 mL L(-1); pH 3.8) and methanol (17:83, v/v) was used as mobile phase and chromatographic separation was achieved on a Shimpack CLC-ODS column. The eluate was monitored by a fluorescence detector with respective excitation and emission wavelengths of 265 and 315 nm. The analytical method was linear over the concentration range of 0.025-10 microg mL(-1) of clarithromycin in human serum with a limit of quantification of 0.025 microg mL(-1). The assay is sensitive enough to measure drug levels obtained in human single dose studies. In the present method, sensitivity and run time of analysis have been improved, and successfully applied in a bioequivalence study of three different clarithromycin preparations in 12 healthy volunteers.

Anti-Bacterial Agents↗
PubMed2006

Determination of clarithromycin in human plasma by liquid chromatography-electrospray ionization tandem mass spectrometry.

A rapid and sensitive method has been developed for the determination of clarithromycin in human plasma with liquid chromatography-tandem mass spectrometry. Clarithromycin and the internal standard, telmisartan were precipitated from the matrix (50 microl) with 200 microl acetonitrile and separated by HPLC using formic acid:10 mM ammonium acetate:methanol (1:99:400, v/v/v) as the mobile phase. The assay based on detection by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring mode was finished within 2.4 min. Linearity was over the concentration range 10-5000 ng/ml with a limit of detection of 0.50 ng/ml. Intra- and inter-day precision measured as relative standard deviation were <3.73% and <9.93%, respectively. The method was applied in a bioequivalence study of two tablet formulations of clarithromycin.

Anti-Bacterial Agents↗
PubMed1996

Depression of the N-demethylation of erythromycin, azithromycin, clarithromycin and clindamycin in murine Toxoplasma infection.

The N-demethylation of macrolides was studied in a murine model of infection. Mice were infected with a cystogenic strain of Toxoplasma gondii (20 or 40 cysts/mouse) and microsomes were prepared from liver homogenates and jejunum villus tip enterocytes on day 10 post-infection. The rate of N-demethylation of the anti-Toxoplasma macrolides azithromycin, clarithromycin and clindamycin was investigated and compared to that of the macrolide erythromycin, a marker of activity of the cytochrome P-450 3A (CYP3A) mono-oxygenases. In infected mice (20 cysts/mouse), the rate of N-demethylation fell in the liver and jejunum for erythromycin (-25% and -35%, respectively), azithromycin (-12% and -10%, respectively), clarithromycin (-23% and -21%, respectively) and clindamycin (-20% and -28%, respectively). The degree of hepatic depression was more marked in mice receiving a 40-cysts burden: for erythromycin (-54%), azithromycin (-29%), clarithromycin (-49%) and clindamycin (-47%).

Animals↗
PubMed2001

[Phlebitis due to intravenous administration of macrolide antibiotics. A comparative study of erythromycin versus clarithromycin].

BACKGROUND: To know and to compare the incidence of phlebitis due to intravenous administration of macrolide antibiotics erythromycin and clarithromycin. PATIENTS AND METHOD: Non-randomized prospective study of consecutive patients who were diagnosed of community pneumonia and treated with intravenous macrolides (19 with erythromycin and 25 with clarithromycin). RESULTS: The cumulative incidence of phlebitis in patients treated with erythromycin was 78.9% (incidence rate of 0.40 episodes/patient-day) and in those treated with clarithromycin 76% (incidence rate of 0.35 episodes/patient-day). CONCLUSIONS: The risk of phlebitis is high and similar with intravenous administration of both macrolides.

Anti-Bacterial Agents↗
PubMed2001

Comparative serum bactericidal activity of clarithromycin and azithromycin against macrolide-sensitive and resistant strains of Streptococcus pneumoniae.

The serum pharmacodynamics of clarithromycin and azithromycin were studied against isolates of S. pneumoniae, including efflux resistant (M. phenotype) strains, by analyzing their serum bactericidal activity (SBA) over time. Normal healthy subjects were given a single 500 mg oral dose of these macrolides and serum samples were collected over 12 hrs. Paired isolates with MICs ranging from 0.25 ug/ml to 8.0 ug/ml were analyzed. Prolonged (at least 6 hrs) SBA was observed with clarithromycin for strains with MICs < or = 2.0 ug/ml. No SBA was observed in strains with MICs >or = 4.0 ug/ml. Azithromycin exhibited SBA for at least 6 hrs for strains up to a MIC = 0.5 ug/ml. No SBA was observed for isolates with MICs > or = 1.0 ug/ml. In contrast to azithromycin, clarithromycin exhibited SBA for at least one-half of its normal dosing interval against S. pneumoniae strains well above its current susceptibility breakpoint concentration of 0.25 microg/ml. These findings may have relevance to the ongoing debate as to the appropriate susceptibility breakpoints for the newer macrolides.

Administration, Oral↗
PubMed1997

Susceptibility of twenty penicillin-susceptible and -resistant pneumococci to levofloxacin, ciprofloxacin, ofloxacin, erythromycin, azithromycin, and clarithromycin by MIC and time-kill.

This study uses MIC and time-kill methodology to examine the antipneumococcal activity of levofloxacin, ciprofloxacin, ofloxacin, erythromycin, azithromycin, and clarithromycin against 20 pneumococci. Ten strains had levofloxacin MICs of 1.0 microgram/ml, and ten levofloxacin MICs of 2.0 micrograms/ml. Five strains in each group were macrolide susceptible, and five were macrolide resistant. MICs for ciprofloxacin and ofloxacin ranged from 0.5 to 4.0 micrograms/ml and 1.0 to 8.0 micrograms/ml, respectively. MICs of erythromycin, azithromycin, and clarithromycin were similar for macrolide susceptible strains, ranging between 0.004 to 0.06 microgram/ml, and were > or = 128.0 micrograms/ml for macrolide resistant strains. The three quinolones were bactericidal (99.9% killing) for all macrolide-susceptible strains at 2 x MIC at 24 h. The three quinolones yielded 99% killing of all strains after 12 h at 2 x MIC, and 90% killing of all strains after 6 h at the MIC of levofloxacin and ciprofloxacin and 2 x MIC for ofloxacin. Levofloxacin yielded 90% killing of all strains after 4 h at 2 x MIC and ofloxacin at 4 x MIC. For macrolide-susceptible strains, erythromycin and clarithromycin were bactericidal for 9 of 10 strains after 24 h at 4 x and 2 x MIC, respectively, and azithromycin was bactericidal after 24 h at 2 x MIC for 8 of 10 strains. All three macrolides were bactericidal after 12 h only, while 90% killing occurred in 9 of 10 strains at 8 x MIC after 6 h. Quinolone kill kinetics were similar for the 10 macrolide-resistant strains. For macrolide-resistant strains, at 64 to 128.0 micrograms/ml, virtually no decrease in count was seen, with no bactericidal effect.

Anti-Bacterial Agents↗
PubMed1998

Comparison of bactericidal activity after multidose administration of clarithromycin, azithromycin, and ceruroxime axetil against Streptococcus pneumoniae.

The objective of this study was to compare the duration of serum bactericidal activity (SBA) for clarithromycin, azithromycin, and cefuroxime axetil in 12 young healthy volunteers after 5 days of therapy (dosed to steady-state) against two strains each of penicillin (PCN)-susceptible, -intermediate, and -resistant Streptococcus pneumoniae. This was a randomized, 3-way crossover study. All isolates were susceptible to clarithromycin (MICs 0.125 mg/l) and azithromycin (MICs 0.25-0.5 mg/l), while cefuroxime axetil susceptibilities correlated with PCN. Results showed that SBA was maintained for 100% of the dosing interval for clarithromycin and 50-100% for azithromycin regardless of PCN susceptibility when standard doses were employed. Cefuroxime axetil was active only against the PCN-susceptible isolate for 50% of the dosing interval, indicating that it should only be used for PCN-susceptible S. pneumoniae.

Anti-Bacterial Agents↗
PubMed2002

Surgery for Mycobacterium avium complex lung disease in the clarithromycin era.

OBJECTIVE: Since the introduction of clarithromycin, it has been assumed that pulmonary Mycobacterium avium complex (MAC) disease can be treated with medication alone. This study examines whether surgery can still play an important role in the management of MAC lung disease in the current era. METHODS: Between April 1993 and January 2001, 21 patients (11 men and 10 women) underwent a pulmonary resection for MAC infection. The median age of the patients was 56 years (range: 27-67 years). None of the patients were immunocompromised. Regimens employing clarithromycin were initiated preoperatively in all patients. The indications for surgery were failure of drug therapy in 19 patients and discontinuation of chemotherapy because of drug toxicity in two patients. The pulmonary resections (19 right lung, 2 left lung) performed included lobectomy in 16 patients, pneumonectomy in three, bilobectomy in one, and lobectomy plus segmentectomy in one. RESULTS: All of the patients survived the surgery. Six major postoperative complications occurred in six patients (28.6%) and these included two bronchopleural fistulas after right pneumonectomy, two space problems, one prolonged air leak, and one case of interstitial pneumonia. All postoperative complications were manageable, and four of these were treated surgically. All patients had sputum-negative status after their operation. Relapse occurred in two patients (9.5%) at six months and two years postoperative, respectively. The first patient, who originally had a right upper lobectomy, underwent a left upper lobectomy during the follow-up period, attaining sputum conversion. The second patient underwent a right pneumonectomy and then died of respiratory failure four years postoperatively. This one late death was the only fatality. CONCLUSIONS: Although it is associated with relatively high morbidity, surgery provides a high sputum conversion rate for patients whose MAC disease responds poorly to drug therapy. Even in the present clarithromycin era, pulmonary resection remains the treatment of choice when MAC lung disease has not been successfully eradicated by drug treatment alone.

Adult↗
PubMed2002

Sensitive liquid chromatography-tandem mass spectrometry method for the determination of clarithromycin in human plasma.

A sensitive method for the determination of clarithromycin in plasma is described, using high-performance liquid chromatographic separation with tandem mass spectrometric detection. Samples were prepared using liquid-liquid extraction and separated on a Supelco Discovery C18 column with a mobile phase consisting of acetonitrile, methanol and acetic acid. Detection was performed by a PE SCIEX API 2000 mass spectrometer in the multiple reaction monitoring (MRM) mode (LC-MS-MS) using TurbolonSpray ionization and monitoring the transition of the protonated molecular ion for clarithromycin at m/z 748.5 (M+1) to the predominant product ion of m/z 158.2. The mean recovery of clarithromycin was 87.3%, with a lower limit of quantification of 2.95 ng/ml when using 0.3-ml plasma. This high-throughput method was used to quantify 230 samples per day, and is sufficiently sensitive to be employed in pharmacokinetic studies.

Anti-Bacterial Agents↗
PubMed2000

Acid-catalyzed degradation of clarithromycin and erythromycin B: a comparative study using NMR spectroscopy.

One of the major drawbacks in the use of the antibiotic erythromycin A is its extreme acid sensitivity, leading to degradation in the stomach following oral administration. The modern derivative clarithromycin degrades by a different mechanism and much more slowly. We have studied the pathway and kinetics of the acid-catalyzed degradation of clarithromycin and of erythromycin B, a biosynthetic precursor of erythromycin A which also has good antibacterial activity, using (1)H NMR spectroscopy. Both drugs degrade by loss of the cladinose sugar ring and with similar rates of reaction. These results suggest that erythromycin B has potential as an independent therapeutic entity, with superior acid stability compared with erythromycin A and with the advantage over clarithromycin of being a natural product.

Acids↗
PubMed2000

Factors that may affect treatment outcome of triple Helicobacter pylori eradication therapy with omeprazole, amoxicillin, and clarithromycin.

Factors affecting Helicobacter pylori eradication rate with omeprazole (OME), clarithromycin (CL), and amoxicillin (AMO) have not been extensively studied. We have investigated the effect of age, sex, smoking, ulcer disease, compliance with therapy, H. pylori colonization density, degree and activity of antral gastritis, the coexistence of corpus gastritis, and the presence of lymphoid follicles on H. pylori eradication rate. We studied 80 consecutive H. pylori-positive patients, with duodenal ulcer (N = 35) or nonulcer dyspepsia (N = 45) treated with OME 20 mg, CL 500 mg, and AMO 1 g, each given twice daily for 10 days. H. pylori was eradicated in 71/80 (88.8%, 95% CI 82-96%) patients. The regimen failed to eradicate the only strain (1.8%, 95% CI 0-5.2%) that was clarithromycin resistant. Multivariate discriminant analysis showed that two histological variables (Wilks lambda = 0.74, chi2 = 23.41, df = 2, P< 0.001), absence of lymphoid follicles in routine gastric biopsies (F = 13.63, P<0.001) and coexistence of antral and body gastritis (F = 13.68, P<0.001), significantly increased H. pylori eradication rate. No other factor examined predicted H. pylori eradication with this regimen. Our data suggest that body gastritis is a positive and presence of lymphoid follicles in routine gastric biopsies is a negative predictive factor of treatment outcome with the omeprazole, clarithromycin, and amoxicillin regime.

Amoxicillin↗
PubMed2001

Clarithromycin resistance, but not CYP2C-19 polymorphism, has a major impact on treatment success in 7-day treatment regimen for cure of H. pylori infection: a multiple logistic regression analysis.

Mutations in the gene encoding the CYP2C-19 enzyme for PPI metabolism have been shown to enhance the chance for a cure in a H. pylori-positive patients using a two-week dual-therapy regimen involving omeprazole and amoxicillin. However, the impact of CYP2C-19 genetic polymorphism on eradication rates of a one-week triple-therapy regimen has not been examined. In this cohort study, 156 H. pylori-positive peptic ulcer or NUD patients who presented to our university hospital were recruited. They were treated by one-week omeprazole-amoxicillin-clarithromycin therapy. Host and bacterial predictive factors including H. pylori susceptibility and CYP2C-19 genotyping, as well as cure rate for H. pylori infection, were studied. Cure rate was 85.9% (95% CI: 79-91%) on an intent to treat (ITT) basis. By multiple logistic regression analysis, only clarithromycin resistance had a significant impact on treatment success (odds ratio 28.7: 95% CI: 6-172). CYP2C-19 genetic polymorphism was not associated with a significant change in cure rate. These observations indicate only clarithromycin susceptibility, not CYP2C-19 polymorphism, has a major impact on the treatment success when using a seven-day OAC H. pylori treatment regimen.

Amoxicillin↗
PubMed1998

One-week triple therapy with lansoprazole, clarithromycin, and metronidazole to cure Helicobacter pylori infection in peptic ulcer disease in Korea.

The efficacy and acceptability of classical bismuth triple therapy may be limited by poor patient compliance and adverse effects. It is widely agreed that improved, simpler, and reliable therapies are needed to cure Helicobacter pylori infection and foster patient compliance. We evaluated the efficacy and side effects of a Bazzoli triple therapy substituting lansoprazole for omeprazole for H. pylori infection in active peptic ulcer in Korea (30 mg of lansoprazole, 250 mg of clarithromycin, and 400 mg of metronidazole, all twice daily). H. pylori status was evaluated by rapid urease test, histology, and culture at entry and four or more weeks after ending antimicrobial therapy. Fifty-eight patients (mean age: 43 years) with gastric (N = 30) or duodenal ulcer (N = 28) and H. pylori infection were studied. H. pylori was cured in 47 (81%, 95% CI = 69-90%). Mild side effects, including vomiting, diarrhea, and itching, were observed in four patients (7%). Compliance averaged 95%. Fifty-five ulcers (95%) were healed. Pretreatment pylorobulbar deformity was observed in 49 patients (85%), and in 43 (88%) the deformity disappeared after treatment. Pretreatment metronidazole and clarithromycin resistance was observed in 87% and 2% of patients, respectively. The cure rate of H. pylori infection was significantly higher in patients >50 years of age than those <50. Treatment with low-dose one-week lansoprazole, clarithromycin, and metronidazole resulted in a relatively low cure rate, but was well tolerated. Studies to define the optimal duration, dose, and dosing interval of this combination therapy in Korea are needed.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1999

Effect of intravenous clarithromycin on interdigestive gastroduodenal motility of patients with functional dyspepsia and Helicobacter pylori gastritis.

Gastroduodenal motility of 16 patients complaining of functional dyspepsia and Helicobacter pylori gastritis was recorded by means of a low-compliance manometric system with four recording ports in the stomach and four in the duodenum. Clarithromycin (CLA) 250 mg (group A: 8 patients) or normal saline solution (group B: 8 patients) was infused intravenously randomly and in double-blind manner 30 min after the end of the first recorded activity front (AF) of the migrating motor complex or, in the absence of AFs, after 200 min of recording, continuing the recording until an AF was observed during the subsequent 200 min. CLA administration was followed by a typical gastroduodenal AF in a significantly higher number of patients than saline administration. In addition, the time-lag between the drug administration and the appearance of AFs was 22 min +/-7.4 (mean +/- SD), significantly shorter than after saline (109+/-56 min) and the CLA-related duodenal AFs showed a duration of 7.4 min +/-1.6 in group A, significantly longer than that of the spontaneous AFs (3.5 min +/-1), while in group B AF duration after saline was not significantly different from that of the spontaneous ones. In conclusion, clarithromycin is able to stimulate cyclic interdigestive gastroduodenal motility. This prokinetic property of clarithromycin is not unexpected because it is a macrolide like erythromycin, the prokinetic activity of which is well known, and could be utilized for therapeutic uses.

Adolescent↗