Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Clarithromycin”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34Linked to original sources

Emergence and persistence of macrolide resistance in oropharyngeal flora and elimination of nasal carriage of Staphylococcus aureus after therapy with slow-release clarithromycin: a randomized, double-blind, placebo-controlled study.

To investigate the effect of slow-release (SR) clarithromycin on colonization and the development of resistance in oropharyngeal and nasal flora, a double-blind, randomized, placebo-controlled trial was performed with 8 weeks of follow-up. A total of 296 patients with documented coronary artery disease were randomized in the preoperative outpatient clinic to receive a daily dose of SR clarithromycin (500 mg) (CL group) or placebo tablets (PB group) until the day of surgery. Nose and throat swabs were taken before the start of therapy, directly after the end of therapy, and 8 weeks later. The presence of potential pathogenic bacteria was determined, and if they were isolated, MIC testing was performed. Quantitative culture on media with and without macrolides was performed for the indigenous oropharyngeal flora. In addition, analysis of the mechanism of resistance was performed with the macrolide-resistant indigenous flora. Basic patient characteristics were comparable in the two treatment groups. The average number of tablets taken was 15 (standard deviation = 6.4). From the throat swabs, Haemophilus parainfluenzae was isolated and carriage was not affected in either of the treatment groups. Nasal carriage of Staphylococcus aureus, however, was significantly reduced in the CL group (from 35.3 to 4.3%) compared to the PB group (from 32.4 to 30.3%) (P < 0.0001; relative risk [RR], 7.0; 95% confidence interval [CI], 3.1 to 16.0). Resistance to clarithromycin was present significantly more frequently in H. parainfluenzae in the CL group after treatment (P = 0.007; RR, 1.6; 95% CI, 1.1 to 2.3); also, the percentage of patients with resistance to macrolides in the indigenous flora after treatment was significantly higher in the CL group (31 to 69%) (P < 0.0001; RR, 1.9; 95% CI, 1.4 to 2.5). This persisted for at least 8 weeks. This study shows that besides the effective elimination of nasal carriage of S. aureus, treatment with SR clarithromycin for approximately 2 weeks has a marked and sustained effect on the development of resistance in the oropharyngeal flora for at least 8 weeks.

Aged↗

Impact of clarithromycin resistance on eradication of Helicobacter pylori in infected adults.

The outcome of Helicobacter pylori infection was analyzed in 114 dyspeptic patients treated with triple-drug therapy including clarithromycin. Clarithromycin resistance (in 20.2% of our isolates) was mainly caused by an A2142G mutation in the 23S rRNA gene of H. pylori. H. pylori eradication was obtained in all patients with clarithromycin-susceptible isolates but not in any patients with clarithromycin-resistant isolates (P = 0.0001). Therefore, it would be useful to conduct H. pylori antimicrobial susceptibility testing of the first gastric biopsy culture before choosing the first three drugs for therapy of infected patients.

Adult↗

PCR-based diagnosis of Helicobacter pylori infection and real-time determination of clarithromycin resistance directly from human gastric biopsy samples.

A novel PCR detection assay that amplifies the Helicobacter pylori-specific vacuolating cytotoxin gene (vacA) and thus enables rapid diagnosis of infection is described. Additionally, a real-time probe hybridization melting point analysis assay to detect all three mutations in the 23S rRNA gene associated with clarithromycin resistance was applied directly to antral gastric biopsy samples. Comparison with culture and an alternative PCR assay targeting the 16S rrn gene showed that the vacA assay was sensitive and specific when tested on biopsy samples from 121 patients. Clarithromycin susceptibilities could be determined in the majority (92.3%) of culture-positive gastric biopsy samples analyzed, four of which generated melting peaks indicative of clarithromycin resistance by either an A-->G or A-->C mutation. The presence of the mutations correlated with the clarithromycin disk diffusion sensitivities of matched cultures. This PCR-based system was simple to perform and could be completed in 3 to 4 h, thereby overcoming the delays associated with conventional culture methods for H. pylori identification and susceptibility testing.

Anti-Bacterial Agents↗

Eradication of Helicobacter pylori with clarithromycin and omeprazole.

Clarithromycin, a new and well tolerated, acid stable macrolide antibiotic, has a similar antimicrobial spectrum to erythromycin but a better in vitro MIC90 (0.03 microgram/l-1) against Helicobacter pylori (H pylori). This study aimed at determining the eradication rate using clarithromycin 500 mg thrice daily and omeprazole 40 mg daily for two weeks. Patients were given an endoscopy and H pylori status assessed by antral culture (microaerobic conditions, for up to 10 days), antral and corpus histology tests (haematoxylin and eosin/Gimenez stains), and 13C-urea breath test (13C-UBT, European standard protocol, positive result = excess delta 13CO2 excretion > 5 per mil). Compliance was assessed by returned tablet counts. H pylori clearance at the end of treatment and eradication four weeks after finishing treatment were assessed by the 13C-UBT. Seventy three patients (54 men, median age 45 years) with duodenal ulcers (n = 42) or duodenitis/non-ulcer dyspepsia (n = 31) all with a positive 13C-UBT (mean (SEM) excess delta-13CO2 excretion = 26.6 (4.9) per mil) and either positive antral histology (n = 72) or positive antral culture (n = 35) were studied. Before treatment 2/27 (7%) isolates of H pylori were resistant to clarithromycin and five isolates were resistant to metronidazole. In 70/73 (96%) the 13C-UBT was negative immediately after finishing treatment. Four weeks later the 13C-UBT was negative in 57/73 (mean (SEM) excess delta 13CO2 excretion = 1.2 (0.3) per mil, eradication rate = 78%). Forty eight (66%) patients experienced a metallic taste while taking the tablets. Although four (5%) patients, however, could not complete the course of treatment, in only one of these four was H pylori not eradicated. These results show that duel therapy with clarithromycin and omeprazole is well tolerated. With an eradication rate of 78% it is an effective treatment for metronidazole resistant H pylori and may be an alternative to standard triple therapy.

Adult↗

Helicobacter pylori specific nested PCR assay for the detection of 23S rRNA mutation associated with clarithromycin resistance.

BACKGROUND: Clarithromycin is one of the most important antibiotics for Helicobacter pylori eradication. However, 5-10% of strains are reported to be resistant. It has been shown that one point mutation in the 23S rRNA gene is associated with resistance to clarithromycin. AIMS: To establish a polymerase chain reaction (PCR) system which amplifies a segment of the 23S rRNA gene containing the mutation points with primers specific for H pylori, so that H pylori infection and the mutation associated with clarithromycin resistance can be examined simultaneously. METHODS: To detect H pylori infection and the mutation simultaneously, primers specific for the H pylori 23S rRNA gene were designed based on sequence conservation among H pylori strains and sequence specificity as compared with other bacteria. DNA from 57 cultured strains and from 39 gastric juice samples was amplified in the seminested 23S rRNA PCR. Clinical applicability was evaluated in 85 patients. RESULTS: DNA samples from 57 cultured strains were all amplified. The novel assay and the urease A PCR agreed in 37/39 gastric juice samples with no false positives. The assay did not amplify the DNA of bacteria other than H pylori. Eight of 85 samples had the mutation before treatment. In clarithromycin based treatment, eradication was achieved in 2/5 (40%) with the mutation and 29/34 (85%) without the mutation. CONCLUSION: The assay using gastric juice is quick (within 12 hours) and non-invasive (endoscopy not required), enabling rapid initiation of appropriate antibiotic treatment.

Anti-Bacterial Agents↗

In vitro effects of clarithromycin on human polymorphonuclear leukocyte functions.

BACKGROUND: It has been shown that antibacterial agents affect polymorphonuclear leukocytes (PMNs), which are active in the body's first line of defense, in different ways. However, few studies have investigated the effects of tablet dosage forms as opposed to pure powder forms. There is a need to demonstrate the clinical relevance of previous results with commercially available products. METHODS: We examined the effects of clarithromycin solutions, prepared separately from either pure powder or commercially available tablets (250 mg), on human PMNs. The in vitro effects of each solution, adjusted to therapeutic concentration (1 mg/l), on PMN adherence, chemotaxis, phagocytosis, candidacidal capacity and superoxide production were studied. RESULTS: Solutions prepared from pure clarithromycin powder did not affect the adherence, phagocytosis or superoxide production of PMNs, but did inhibit (p<0.05) chemotaxis and candidacidal capacity. By contrast, a decrease (p<0.05) in all functions except phagocytosis was observed with solutions prepared from the tablet dosage form of clarithromycin. CONCLUSION: The results of this study suggest that the tablet dosage form of clarithromycin may have a more pronounced inhibitory effect on human PMN functions than solutions prepared from the pure powder form.

Anti-Bacterial Agents↗

Triple therapy with omeprazole, amoxicillin and clarithromycin is effective against Helicobacter pylori infection in gastric ulcer patients as well as in duodenal ulcer patients. Results of a randomized controlled trial in Japan.

BACKGROUND/AIMS: There have been few reliable published studies permitting assessment of therapeutic regimens for Helicobacter pylori infection in gastric ulcer (GU) patients. The aim of the present study was to evaluate the efficacy of omeprazole-based dual and triple therapy regimens, both including clarithromycin, for the cure of H. pylori infection in active GU and duodenal ulcer (DU) patients. The study was conducted in Japan, a country in which GU is more prevalent than DU. METHODS: Two hundred and thirty-four consecutive peptic ulcer patients (GU: n = 124; DU: n = 103; GDU: n = 7) suffering from H. pylori infection were randomly treated with either omeprazole 20 mg b.i.d. + amoxicillin 500 mg q.i.d. + clarithromycin 400 mg b.i.d. (OAC) or with omeprazole 20 mg b.i.d. + clarithromycin 400 mg b.i.d. (OC) for 14 days. H. pylori infection was evaluated by histology and culture from antral and corpus biopsies 6 weeks after completing antimicrobial therapy. RESULTS: Follow-up data were available in 202 patients. The cure rates of H. pylori infection in GU patients were 83.9% (47/56) with OAC and 59. 2% (29/49) with OC. Corresponding rates in DU patients were 91.5% (43/47) and 70.5% (31/44), respectively. The cure rates with OAC were significantly higher than those with OC (p < 0.001, chi2 test). The cure rates in GU patients were lower than those in DU patients for both regimens, but these differences were not statistically significant. Side effects were generally mild and did not interfere with compliance. One patient in the OAC group and 2 patients in the OC group complained of severe side effects that led to therapy discontinuation. CONCLUSIONS: Triple therapy with omeprazole, amoxicillin and clarithromycin is a safe and effective regimen for the cure of H. pylori infection in GU patients as well as in DU patients. We recommend this triple regimen as a first-line treatment in all patients with peptic ulcers associated with H. pylori infection in Japan.

Adolescent↗

Prospective evaluation of the impact of amoxicillin, clarithromycin and their combination on human gastrointestinal colonization by Candida species.

BACKGROUND: Amoxicillin and clarithromycin have been used extensively for the eradication of Helicobacter pylori. However, no study has examined the impact of their combination on the Candida albicans concentration of the gastrointestinal (GI) tract. This is the first study examining and comparing directly the effect of amoxicillin, clarithromycin and their combination on the C. albicans concentration of the human GI tract. METHODS: Thirty-three adult patients (11 in each antibiotic group) were studied prospectively. Quantitative stool cultures for Candida were conducted at the beginning, the end and 1 week after the discontinuation of antibiotic treatment. RESULTS: All three regimens increased the GI colonization in patients by Candida. The combination of amoxicillin with clarithromycin caused the highest increase; however, this was not statistically significant. CONCLUSION: Amoxicillin and clarithromycin used either alone or in combination cause a small to moderate increase in GI colonization by Candida. Hence, these drugs could be safely used in patients at risk for candidiasis originating from the GI tract.

Administration, Oral↗

High-dose omeprazole plus amoxicillin or clarithromycin cures Helicobacter pylori infection in duodenal ulcer disease.

Treatment with omeprazole plus amoxicillin or clarithromycin resulted in encouraging Helicobacter pylori cure rates in pilot and controlled studies. The present prospective, randomized study was designed to compared the efficacy and safety of amoxicillin and clarithromycin as constituents of omeprazole-enhanced antibiotic therapy of H. pylori infection. Fifty patients with active duodenal ulcer disease and histologically and/or culturally confirmed H. pylori colonization of the gastric mucosa were treated with omeprazole (day 1-14: 40 mg twice daily, day 15-42: 20 mg once in the morning). The patients were randomly assigned to receive either amoxicillin (1 g twice daily; group I: n = 25) or clarithromycin (500 mg twice daily; group II: n = 25) during the first 2 weeks of treatment. The patients of group I and II had comparable demographic and clinical characteristics. One patient of group I was lost to follow-up. H. pylori infection was cured in 87.5% of group I and 84.0% of group II (p = 1.00). All ulcers had healed after 6 weeks of omeprazole treatment. Pain relief occurred within the first day of treatment in the majority of patients of both groups (p = 0.89). Minor side effects were recorded in 6 patients of group I and in 4 patients of group II (25 vs. 16%; p = 0.50). In 1 female patient amoxicillin had to be withdrawn after 3 days because of nausea and emesis. In conclusion, 2 weeks of treatment with omeprazole plus amoxicillin or clarithromycin are highly and equally effective regimens to cure H. pylori infection in patients with duodenal ulcer disease.

Amoxicillin↗

Pharmacokinetic interactions between erythromycin, clarithromycin, roxithromycin and phenytoin in the rat.

The effects of the macrolide antibiotics, erythromycin, clarithromycin and roxithromycin, on the pharmacokinetic profile of phenytoin were studied in rats. Animals were injected with phenytoin (100 mg/kg, i.p.) daily for 4 days and then they were given phenytoin (20 mg/kg, i.p.) alone or the same dose of phenytoin together with erythromycin (50 mg/kg, i.p.), clarithromycin (50 mg/kg, i.p.) or roxithromycin (50 mg/kg, i.p.). In another set of experiments, the same protocol was followed except that erythromycin (100 mg/kg), clarithromycin (100 mg/kg) and roxithromycin (100 mg/kg) were given by the oral route. The concentrations of phenytoin in plasma were determined using a high-performance liquid chromatographic method. The area under the curve the maximum plasma concentration and the elimination half-life (t1/2) of phenytoin were significantly (p < 0.05) increased by the macrolides. In addition, the macrolides significantly (p < 0.05) reduced the level of hepatic cytochrome P-450 in the rats. These results suggest that a potentially harmful drug-drug interaction may occur if phenytoin is administered concurrently with erythromycin, clarithromycin or roxithromycin.

Animals↗

Effect of clarithromycin on nasal mucus properties in healthy subjects and in patients with purulent rhinitis.

Erythromycin inhibits mucus glycoconjugate secretion from airway cells in vitro and may increase mucus clearance in patients with asthma or diffuse panbronchiolitis. Because mucus hypersecretion is common in purulent rhinitis, we questioned whether clarithromycin would change the properties of nasal mucus from subjects without sinus disease and from patients with acute purulent rhinitis. Nasal secretions were collected before and after nasal methacholine challenge from 10 adults without nasal symptoms and without methacholine from 10 patients with purulent rhinitis. After 2 wk of oral clarithromycin (500 mg twice daily), secretions were again collected from both groups. Secretions were analyzed for viscoelasticity, cohesion, hydration, and ciliary and airflow (sneeze) transportability. Compared with secretions from healthy subjects, rhinitis secretions had decreased wettability (contact angle on Teflon 100 degrees versus 84.67 degrees; p = 0.001), increased cohesion (36.8 versus 24.3 mm; p = 0.003), decreased sneeze clearability (20.6 versus 32 mm; p = 0.04), and increased percent solids (4.61 versus 2.82%; p = 0.04). After clarithromycin, the rheology, hydration, cohesion, and transportability of the rhinitis secretions were similar to those of the postclarithromycin secretions from the healthy subjects. Secretion volume also decreased (500.1 versus 28.3 mg; p = 0.01), and mucociliary transportability increased by 30% (0.76 versus 0.99; p = 0.005). Although clarithromycin reduced mucus secretion in both rhinitis patients and normal subjects, it did not alter the secretory response to methacholine.

Acute Disease↗

Effect of clarithromycin regimen for Mycobacterium avium complex pulmonary disease.

We have investigated the efficacy of a clarithromycin-containing four-drug regimen for Mycobacterium avium complex (MAC) pulmonary disease in 46 patients without acquired immunodeficiency syndrome (AIDS). The patients were 14 males and 32 females with a mean age of 60.9 +/- 11.5 yr. Patients received 10 mg/kg/d of clarithromycin plus ethambutol, rifampin, and initial kanamycin and subsequent quinolone for 24 mo. Seven patients (15.2%) were dropped in the first 6 mo. Among 39 patients who received more than 6 mo of therapy, 28 patients (71.8%) converted their sputa to negative: 26 of 31 patients (83.9%) infected with clarithromycin-susceptible strains and two of eight patients (25.0%) with resistant or intermediate strains. The timing of sputum conversion was 3.6 +/- 1.9 mo, with a range of 2 to 9 mo. The conversion rate was significantly lower in patients who were infected with clarithromycin-resistant or intermediate strains, who had had prior therapy (55.0% versus 89.5%), or who were acid-fast bacilli (AFB) smear-positive at entry (60.7% versus 100%). The age and sex of patients, the species of pathogen (M. avium or M. intracellulare), type and extent of the disease, and the use of kanamycin did not significantly affect the conversion rate. Although the regimen was efficacious for newly treated patients, frequent adverse reactions and a low conversion rate of sputum in retreated patients are problems that remain to be solved.

Adult↗

Assessing the clinical significance of botanical supplementation on human cytochrome P450 3A activity: comparison of a milk thistle and black cohosh product to rifampin and clarithromycin.

Phytochemical-mediated modulation of cytochrome P450 enzymes (CYPs) may underlie many herb-drug interactions. This study's purpose was to assess the effects of milk thistle and black cohosh supplementation on CYP3A activity and compare them to a clinically recognized inducer, rifampin, and inhibitor, clarithromycin. Healthy volunteers were randomly assigned to receive a standardized milk thistle (900 mg) or black cohosh (80 mg) supplement for 14 days. Subjects also received rifampin (600 mg) and clarithromycin (1000 mg) for 7 days as positive controls for CYP3A induction and inhibition, respectively. Midazolam was administered orally before and after each supplementation and control period. The effects of milk thistle, black cohosh, rifampin, and clarithromycin on midazolam pharmacokinetics were determined using noncompartmental techniques. Unlike those observed for rifampin and clarithromycin, midazolam pharmacokinetics was unaffected by milk thistle or black cohosh. Milk thistle and black cohosh appear to have no clinically relevant effect on CYP3A activity in vivo.

Adult↗

Clinical efficacy and tolerance of two new macrolides, clarithromycin and josamycin, in the treatment of patients with acute exacerbations of chronic bronchitis.

The efficacy and safety of oral 500 mg clarithromycin given twice daily and 500 mg josamycin given three times daily were compared for up to 14 days in the treatment of 103 out-patients with acute exacerbations of chronic bronchitis in an open, randomized study. The predominant pathogens isolated were Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus. Clinical cures were experienced by 85% of the clarithromycin-treated patients, with an additional 10% showing improvement. In josamycin-treated patients, 76% of the patients experienced clinical cures and an additional 19% showed improvement. Eradication of the causative pathogen occurred in approximately 95% of the patients in both treatment groups. Adverse events, which all involved the gastro-intestinal tract and were mild, transient and probably related to therapy, were experienced by 5.8% and 7.8%, respectively, of the clarithromycin- and josamycin-treated patients. It is concluded that clarithromycin given twice daily is as effective as josamycin given three times daily.

Adolescent↗

Azithromycin compared with clarithromycin in the treatment of adult patients with acute purulent tracheobronchitis: a cost of illness study.

Adult, professionally active patients with acute purulent tracheobronchitis were treated with azithromycin (3 or 5 days; n = 62) or clarithromycin (7 to 10 days; n = 69) in an open, randomized study. Bronchitis-related costs and treatment efficacy were assessed at day 5-6 and day 14-21. Both antibiotics were of equal clinical efficacy, although the median time to improvement of symptoms was significantly shorter for azithromycin patients than for clarithromycin patients. Some 77% of azithromycin patients and 78% of clarithromycin patients were unable to work for at least 1 day. The total time when patients were unable to work was shorter for azithromycin patients than for clarithromycin patients, but this difference did not remain significant when weekends and holidays were taken into account. Further studies are needed to assess the impact of azithromycin on time to clinical improvement, on lost working days, and on the associated costs.

Absenteeism↗

Bactericidal activity of moxifloxacin compared to grepafloxacin and clarithromycin against Streptococcus pneumoniae and Streptococcus pyogenes investigated using an in vitro pharmacodynamic model.

The aim of the present investigation was to study and compare the killing activity of two new fluoroquinolone compounds, moxifloxacin and grepafloxacin, and a new generation macrolide, clarithromycin, against three clinical isolates of Streptococcus pneumoniae (penicillin-susceptible, -intermediate and -resistant) and two Streptococcus pyogenes (erythromycin-susceptible and -resistant) strains by simulating their human pharmacokinetics in a pharmacodynamic model. Results were achieved by measuring the reduction in viable bacterial count during the 24-h experimental period. All three antimicrobials led to a continuous reduction in the bacterial counts of penicillin-susceptible S. pneumoniae and erythromycin-susceptible S. pyogenes strains, the maximal reduction observed after 8-10 hours being 5-6 logs for moxifloxacin and 3 logs for grepafloxacin; clarithromycin exhibited a similar reduction of 5 logs only after 24 h. No regrowth was observed for any strain after 24 h with any of the antibiotics. The bactericidal activity of both the fluoroquinolones was not affected by penicillin resistance of S. pneumoniae and erythromycin resistance of S. pyogenes. In contrast, clarithromycin was not able to reduce the bacterial count of penicillin-resistant S. pneumoniae and erythromycin-resistant S. pyogenes strains. Moxifloxacin exhibited, within 24 h, higher and faster bactericidal activity than grepafloxacin and clarithromycin against S. pneumoniae, and was not affected by penicillin resistance. These results suggest that moxifloxacin is a promising new agent for treatment of streptococcal infections.

Anti-Bacterial Agents↗

Studies on the development and stability of resistance of Helicobacter pylori to metronidazole and clarithromycin.

Thirty-one strains of Helicobacter pylori, susceptible to metronidazole and clarithromycin, were isolated from 31 biopsy samples from patients with various gastric pathologies. We investigated the possibility of selecting resistant strains and the stability of resistance by exposing isolates to increasing subinhibitory concentrations of metronidazole and clarithromycin using a serial passages technique. Resistance to metronidazole was obtained in 100% of the isolates, while 32.2% displayed resistance to clarithromycin. Resistance to metronidazole was stable in 93.5% (29 of 31) of the isolates, whereas 100% (10 of 10) of the strains were stably resistant to clarithromycin. The stability of the resistance that occurred after three passages on medium containing the two drugs was statistically significant (P <0.001). Thus, the technique of serial passages in vitro could be useful as a first screening in selecting drugs for use in therapeutic protocols for clinical trials.

Anti-Bacterial Agents↗

Comparative analysis of azithromycin and clarithromycin efficacy and tolerability in the treatment of chronic prostatitis caused by Chlamydia trachomatis.

A total of 123 patients, older than 18 years of age, with symptoms of chronic prostatitis and inflammatory findings as well as the presence of Chlamydia trachomatis confirmed by DNA/RNA DIGENE hybridization method in expressed prostatic secretion or in voided bladder urine collected immediately after prostatic massage, were examined. The patients were randomized to receive a total of 4.5 g of azithromycin for 3 weeks, given as a 3-day therapy of 1 x 500 mg weekly or clarithromycin 500 mg b.i.d. for 15 days. Patients' sexual partners were treated at the same time. Clinical and bacteriological efficacy were evaluated 4-6 weeks after the end of therapy. In the group of patients with chronic chlamydial prostatitis the eradication rates (azithromycin 37/46, clarithromycin 36/45) and the clinical cure rates (azithromycin 32/46, clarithromycin 32/45) were not significantly different with regards to the administered drug (p > 0.05). In the group of patients with asymptomatic chlamydial prostatitis the eradication rates (azithromycin 11/16, clarithromycin 10/15) were not significantly different with regards to the administered drug (p = 1.00, OR = 1.1).

Adolescent↗