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 217 records · Page 12Linked to original sources
PubMed1994

Orally administered clarithromycin for the treatment of systemic Mycobacterium avium complex infection in children with acquired immunodeficiency syndrome.

OBJECTIVE: To determine the safety, tolerance, pharmacokinetics, and antimycobacterial activity of orally administered clarithromycin in children with acquired immunodeficiency syndrome and disseminated Mycobacterium avium complex (MAC) infection. DESIGN: Phase I study with a 10-day pharmacokinetic phase followed by a 12-week continuation therapy phase. PATIENTS: Twenty-five patients with a median age of 8.3 years were enrolled. Ten were receiving zidovudine and 13 were receiving didanosine at the time of enrollment. INTERVENTION: Clarithromycin suspension was administered to each patient at one of three dose levels: 3.75, 7.5, and 15 mg/kg per dose every 12 hours. Clarithromycin and antiretroviral pharmacokinetics were measured during single-drug and concurrent-drug administration. Clinical and laboratory monitoring was performed biweekly. MEASUREMENTS AND MAIN RESULTS: Clarithromycin was well tolerated at all dose levels. Plasma clarithromycin concentrations increased proportionately with increasing doses, and significant pharmacokinetic interactions were not observed during concurrent administration with zidovudine or didanosine. Decreases in mycobacterial load in blood were observed only at the highest clarithromycin dose level. Decreased susceptibility to clarithromycin developed rapidly (within 12 to 16 weeks) in the majority of MAC strains isolated from study patients.

AIDS-Related Opportunistic Infections↗
PubMed2003

Effects of cysteine on the pharmacokinetics of intravenous clarithromycin in rats with protein-calorie malnutrition.

Effects of cysteine on the pharmacokinetics of clarithromycin were investigated after intravenous administration of the drug at a dose of 20 mg/kg to control rats (4-week fed on 23% casein diet) and rats with PCM (protein-calorie malnutrition, 4-week fed on 5% casein diet) and PCMC (PCM treated with 250 mg/kg for oral cysteine twice daily during the fourth week). Clarithromycin has been reported to be metabolized via hepatic microsomal cytochrome P450 (CYP) 3A4 to 14-hydroxyclarithromycin (primary metabolite of clarithromycin) in human subjects. It has also been reported that in rats with PCM, CYP3A23 level decreased to 40-50% of control level, but decreased CYP3A23 level in rats with PCM completely returned to control level by oral cysteine supplementation (rats with PCMC). Human CYP3A4 and rat CYP3A23 proteins have 73% homology. In rats with PCM, the area under the plasma concentration-time curve from time zero to time infinity, AUC (567, 853 and 558 microg min/ml for control rats and rats with PCM and PCMC, respectively) and percentage of clarithromycin remaining after incubation with liver homogenate (69.6, 83.9 and 71.7%) were significantly greater than those in control rats and rats with PCMC. Moreover, in rats with PCM, the total body clearance, CL (35.3, 23.4 and 35.8 ml/min/kg), nonrenal clearance, CL(NR) (21.3, 15.2 and 24.1 ml/min/kg) and maximum velocity for the disappearance of clarithromycin after incubation with hepatic microsomal fraction, V(max) (351, 211 and 372 pmol/min/mg protein) were significantly slower than those in control rats and rats with PCMC. However, above mentioned each parameter was not significantly different between control rats and rats with PCMC. The above data suggested that metabolism of clarithromycin decreased significantly in rats with PCM as compared to control due to significantly decreased level of CYP3A23 in the rats. By cysteine supplementation (rats with PCMC), some pharmacokinetic parameters of clarithromycin (AUC, CL, CL(NR) and V(max)) were restored fully to control levels because CYP3A23 level was completely returned to control level in rats with PCMC.

Administration, Oral↗
PubMed2002

Open-label, randomized comparison of the efficacy and tolerability of clarithromycin, levofloxacin, and cefuroxime axetil in the treatment of adults with acute bacterial exacerbations of chronic bronchitis.

BACKGROUND: In the absence of a confirmed pathogen, empiric antimicrobial treatment of patients with acute exacerbations of chronic bronchitis and acute bacterial exacerbations of chronic bronchitis (ABECB) is accepted as standard practice and recommended in treatment guidelines. OBJECTIVE: This study compared the efficacy and tolerability of a 10-day course of 3 antimicrobial regimens commonly used to treat adults with ABECB. METHODS: This prospective, open-label, randomized study assessed clarithromycin 500 mg twice daily, levofloxacin 500 mg once daily, and cefuroxime axetil 250 mg twice daily, each administered for 10 days with food, in patients with ABECB. Efficacy was determined on the basis of the clinical response to treatment and need for hospitalization and/or further antimicrobial therapy. RESULTS: A total of 283 patients (150 men, 133 women) with a mean age of 55 years (range, 29 to 86 years) were randomized to receive clarithromycin (n = 97), levofloxacin (n = 94), or cefuroxime axetil (n = 92). Of 262 clinically assessable patients, clinical cure or improvement occurred in 87.9% (80/91) of those treated with clarithromycin, 87.4% (76/87) of those treated with levofloxacin, and 79.8% (67/84) of those treated with cefuroxime axetil. Eight (8.8%) clarithromycin-treated patients, 6 (6.9%) levofloxacin-treated patients, and 12 (14.3%) cefuroxime axetil-treated patients required a change in antimicrobial therapy to achieve clinical cure/improvement; between-group differences were not significant. No patients treated with clarithromycin required hospitalization for further antimicrobial treatment, compared with 3.4% (3/87) of levofloxacin-treated and 3.6% (3/84) of cefuroxime axetil-treated patients (P = NS). A total of 6.2% (6/97) of clarithromycin-treated patients were prematurely discontinued from treatment due to adverse events, compared with 7.4% (7/94) and 8.7% (8/92) of levofloxacin- and cefuroxime axetil-treated patients, respectively. CONCLUSION: A high rate of clinical efficacy and tolerability was observed in this population of patients with ABECB treated with clarithromycin 500 mg twice daily, levofloxacin 500 mg once daily, or cefuroxime axetil 250 mg twice daily for 10 days.

Acute Disease↗
PubMed2002

A controlled, double-blind, multicenter study comparing clarithromycin extended-release tablets and levofloxacin tablets in the treatment of community-acquired pneumonia.

BACKGROUND: Macrolides and fluoroquinolones are frequently used for the empiric treatment of community-acquired pneumonia (CAP). OBJECTIVE: The aim of the study was to compare the safety profile and efficacy of clarithromycin extended-release (ER) tablets with those of levofloxacin tablets for the treatment of CAP in ambulatory adult patients. METHODS: In a Phase III, double-blind, randomized, parallel-group, multicenter study, ambulatory adult patients (> or = 18 years) with signs and symptoms of CAP received a 7-day course of treatment with either clarithromycin ER (two 500-mg tablets once daily) or levofloxacin (two 250-mg tablets once daily). A diagnosis of CAP was confirmed by radiography of the chest and physical examination, and sputum samples were analyzed to identify etiologic pathogen(s). Tolerability was assessed through subjective reports of adverse events and through changes in physical findings, concomitant medications, and laboratory values. RESULTS: There were no statistically significant differences between treatment groups in terms of sex, age, race, or body weight. The mean age was 50 years (range, 18-91 years). Of 299 patients randomized and treated, 252 were clinically evaluable (128 clarithromycin ER, 124 levofloxacin). The 95% CI for the difference between cure rates demonstrated equivalence of the 2 treatments. Among clinically evaluable patients at the test-of-cure visit, clinical cure rates were 88% (113/128) and 86% (107/124), and radiographic success rates were 95% (117/123) and 88% (104/118) for clarithromycin ER and levofloxacin, respectively. Both treatment regimens were effective in resolving and improving clinical signs and symptoms of CAP. Among clinically and bacteriologically evaluable pa- tients, bacteriologic cure rates were 86% (80/93) and 88% (85/97) for clarithromycin ER and levofloxacin, respectively. No statistically significant differences were observed between the 2 treatment groups in the overall incidence of adverse events. CONCLUSIONS: Clarithromycin ER demonstrated equivalent efficacy and tolerability to the fluoroquinolone levofloxacin in a group of ambulatory adult patients with CAP. Clarithromycin ER also appeared to be safe in the population studied.

Adult↗
PubMed2004

Efficacy and tolerability of once-daily oral telithromycin compared with clarithromycin for the treatment of community-acquired pneumonia in adults.

BACKGROUND: Telithromycin is a new antibacterial agent of the ketolide class designed to provide optimal treatment against common bacterial respiratory tract pathogens. Telithromycin was derived by structural modification of the basic macrolide molecule to allow tight binding to the bacterial ribosome that enhances potency and minimizes the risk for the development of resistant strains. OBJECTIVE: The aim of this study was to compare the efficacy and tolerability of telithromycin 800 mg once daily with those of high-dose clarithromycin (500 mg twice daily), each for 10 days, in the treatment of adult patients with community-acquired pneumonia (CAP). METHODS: This randomized, double-blind, double-dummy, parallel-group clinical trial was conducted at 54 centers in the United States, Canada, Argentina, and Chile. Patients aged >or=18 years with acute CAP were randomized to receive 10-day treatment with oral telithromycin 800 mg once daily (administered as two 400-mg encapsulated tablets in the morning) and placebo (administered as 2 encapsulated tablets identical to the telithromycin in the evening) or high-dose clarithromycin (500 mg administered as two 250-mg identical encapsulated tablets twice daily). The primary outcome measure was clinical outcome at the posttherapy, test-of-cure visit (days 17-24 after the completion of therapy) in the clinically assessable per-protocol population. Secondary efficacy variables included bacteriologic outcome at the posttherapy, test-of-cure visit, and clinical and bacteriologic outcomes at the late posttherapy visit (day 31-45). Tolerability was assessed using investigator observation, patient self-reporting, clinical laboratory data, a 12-lead electrocardiogram, and physical examination (including vital signs). RESULTS: A total of 493 patients were enrolled and 448 patients received >or=1 dose of study medication (224 patients/group). A diagnosis of CAP was confirmed in 416 patients (205 men, 211 women; median age, 43 years; telithromycin, n = 204; clarithromycin, n = 212). Clinical cure rates were 88.3% (143/162) in the telithromycin group and 88.5% ( 138/56) in the clarithromycin group. Bacterial eradication rates were comparable between treatment groups (telithromycin, (28/32) [87.5%]; clarithromycin, (29/30) [96.7%]. Both treatment were fairly well tolerated; adverse events were experienced in 57.0% of the patients treated with telithromycin and 49.1% of those treated with clarithromycin; most of these were assessed as mild. CONCLUSIONS: In this study of adult patients with CAP, telithromycin 800 mg once daily was an effective and fairly well-tolerated regimen for initial empiric treatment, with clinical and bacteriologic efficacy and tolerability equivalent to therapy with high-dose clarithromycin (500 mg twice daily).

Administration, Oral↗
PubMed2006

Effect of clarithromycin on cytokines and chemokines in children with an acute exacerbation of recurrent wheezing: a double-blind, randomized, placebo-controlled trial.

BACKGROUND: Clarithromycin is postulated to possess immunomodulatory properties in addition to its antimicrobial activity. OBJECTIVE: To evaluate the effect of clarithromycin on serum and nasopharyngeal cytokine and chemokine concentrations in children with an acute exacerbation of recurrent wheezing. METHODS: Children with a history of recurrent wheezing or asthma and who presented with an acute exacerbation of wheezing were enrolled in a double-blind, randomized trial of clarithromycin vs placebo. Concentrations of tumor necrosis factor alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta), IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, RANTES, eotaxin, macrophage inflammatory protein 1alpha, macrophage inflammatory protein 1beta, and monocyte chemoattractant protein 1 were measured in serum and/or nasopharyngeal aspirates before, during, and after therapy. Mycoplasma pneumoniae and Chlamydophila pneumoniae infection were evaluated for by polymerase chain reaction and serologic testing. RESULTS: Nasopharyngeal concentrations of TNF-alpha, IL-1beta, and IL-10 were significantly and persistently lower in children treated with clarithromycin compared with placebo. There tended to be a greater effect of clarithromycin on nasopharyngeal cytokine concentrations in patients with evidence of M. pneumoniae or C. pneumoniae infection. No significant differences were detected in serum cytokines for children treated with clarithromycin compared with placebo. CONCLUSION: Clarithromycin therapy reduces mucosal TNF-alpha, IL-1beta, and IL-10 concentrations in children with an acute exacerbation of recurrent wheezing.

Acute Disease↗
PubMed1997

Metronidazole resistance reduces efficacy of triple therapy and leads to secondary clarithromycin resistance.

There has been a significant increase in the prevalence of H. pylori resistance to metronidazole in recent years, while clarithromycin resistance is still relatively rare. In this study we assessed: (1) the effect of primary H. pylori resistance to metronidazole and clarithromycin on the clinical efficacy of a one-week regimen consisting of omeprazole, metronidazole, and clarithromycin; and (2) the rate of acquisition of secondary antimicrobial resistance after treatment failure. Eighty-seven patients with duodenal ulceration or nonulcer dyspepsia were included in the study. The primary metronidazole and clarithromycin resistance rates were 35.6% and 3.4%, respectively (all three pretreatment clarithromycin resistant strains had concurrent metronidazole resistance). H. pylori was eradicated in 81.6% of patients. The eradication rate for fully sensitive isolates was 98.2% (55/56) but was significantly reduced to 57.1% (16/28) for isolates that were resistant to metronidazole alone and 0% (0/3) in cases of dual resistance (P < 0.001). Secondary resistance to clarithromycin was acquired in 58.3% of cases of treatment failure. In areas of high prevalence of primary metronidazole resistance, this is a significant cause of treatment failure with this triple therapy regimen. This leads to the selection of strains with dual resistance that are difficult to eradicate and may contribute to an increase in the prevalence of clarithromycin resistance. In such areas an alternative first-line treatment should be prescribed.

Adult↗
PubMed2001

Ranitidine bismuth citrate with clarithromycin alone or with metronidazole for the eradication of Helicobacter pylori.

BACKGROUND: Both triple therapy with ranitidine bismuth citrate (RBC) plus two antibiotics for 7 days and dual therapy of RBC with clarithromycin for 14 days have been extensively studied; both regimens effectively eradicate Helicobacter pylori. However, few studies have assessed the efficacy of dual therapy given for 7 days. AIM: To compare the efficacy and safety of RBC 400 mg with clarithromycin 500 mg, alone or with metronidazole 400 mg, given twice daily for 7 days for the eradication of H. pylori. METHODS: This single centre, randomized, double-blind study involved 118 patients with dyspepsia or a history of peptic ulcer disease. H. pylori infection was detected initially by CLO test, and confirmed in 109 patients by urea breath test and/or microbiology culture. H. pylori eradication was assessed 4 and 12 weeks after the end of treatment by urea breath test. H. pylori antibiotic susceptibility was assessed pre-study in all patients, and post-treatment in patients with a positive post-treatment urea breath test. Adverse events were recorded throughout the study. RESULTS: H. pylori was eradicated in 93% of patients who received RBC with clarithromycin and metronidazole and in 84% of patients who received RBC with clarithromycin (intention-to-treat rates). Per protocol eradication rates were 98% and 90% for triple therapy and dual therapy, respectively. The eradication of metronidazole-resistant H. pylori was achieved in 100% and 88% of patients following dual therapy and triple therapy, respectively, and acquired resistance to clarithromycin occurred in only one patient following treatment failure. Both treatments were well-tolerated; only one patient (2%) was withdrawn from each treatment group due to adverse events. CONCLUSIONS: RBC with clarithromycin and metronidazole is a highly effective and well-tolerated triple therapy regimen for the eradication of H. pylori. RBC with clarithromycin dual therapy has a similar efficacy, and offers an alternative to triple therapy when there are concerns about treatment with metronidazole or the use of multiple antibiotics. Both regimens are effective against antibiotic-resistant strains of H. pylori.

Adult↗
PubMed1997

The mechanism of cyclosporine toxicity induced by clarithromycin.

AIMS: Recently a number of case reports have described the interaction of clarithromycin with cyclosporine A, resulting in cyclosporine toxicity. This interaction is presumed to take place via the hepatic cytochrome P450 enzyme system. METHODS: Following a case of cyclosporine toxicity and acute renal failure in a transplant patient started on clarithromycin, we investigated the effect of oral clarithromycin on the hepatic P450 system in five healthy normal male volunteers, by means of the erythromycin breath test. RESULTS: Cytochrome P4503A (CYP3A) activity was reduced in all subjects by a mean level of 26% following clarithromycin treatment. This would result in a significant reduction in cyclosporine clearance in patients receiving clarithromycin. CONCLUSIONS: As clarithromycin was shown to inhibit CYP3A activity in all subjects tested, we recommend that a high degree of caution be exercised when clarithromycin is administered to patients receiving cyclosporine therapy or other drugs known to be eliminated by CYP3A-mediated metabolism.

Anti-Bacterial Agents↗
PubMed2000

Clarithromycin-resistance and point mutations in the 23S rRNA gene in Helicobacter pylori isolates from Japan.

BACKGROUND: Resistance of Helicobacter pylori to clarithromycin is mostly due to the point mutations in the 23S rRNA. In Japan, however, the frequency of these mutations has not been fully investigated. Furthermore, no study has used gastric biopsy specimens to detect these point mutations. METHODS: The frequency of primary clarithromycin-resistant H. pylori was examined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Eighty-two strains (42 isolated from patients with gastric cancer and 40 isolated from patients with chronic gastritis) were examined. Two biopsy specimens obtained from patients in whom eradication therapy including clarithromycin had failed were also studied. RESULTS: Either A2143G or A2144G point mutation was detected in 90% of clarithromycin-resistant H. pylori strains. Eight out of 82 strains (9.8%) had either A2143G or A2144G point mutation. Only one out of 42 strains in patients with gastric cancer had A2143G mutation, whereas five strains had A2144G and two had A2143G mutations in 40 strains isolated from control subjects. The proportion was significantly lower in patients with early gastric cancer (P < 0.05). This PCR-RFLP was also applicable for DNA samples extracted from biopsy specimens and infection of clarithromycin-resistant H. pylori was observed. CONCLUSION: The results suggest that the point mutation in the 23S rRNA gene is commonly seen in clarithromycin-resistant H. pylori and it contributes to the treatment failure in Japan. The PCR-RFLP system is a sensitive method by which to diagnose H. pylori infection as well as a simple method for detecting clarithromycin resistance without bacterial culture.

Anti-Bacterial Agents↗
PubMed2004

Studies on the bioequivalence of different strengths of tablets containing clarithromycin.

The aim of the present studies, performed in two different groups of volunteers, was to compare the bioavailability of clarithromycin (CAS 81103-11-9) tablets (Klaromin, test tablets) containing 250 mg (study 1) or 500 mg (study 2) of the drug with reference tablets of the same strength. Each study was conducted according to an open, randomized, single-dose, two-period crossover design in healthy volunteers with a wash-out period from 7 to 14 days. Blood samples were taken up to 24 h in both studies, and concentrations of clarithromycin and its principal active 14-hydroxy metabolite were determined by HPLC method. In the first study, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of clarithromycin were between 0.93 and 1.05 (AUC0-t) as well as between 0.90 and 1.18 (Cmax). In the second study, i.e. after administration of clarithromycin 500 mg tablets, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of clarithromycin were between 0.90 and 1.08 (AUC0-t) as well as between 0.85 and 1.22 (Cmax). All these values were within the acceptance ranges for bioequivalence studies. In both studies, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of 14-hydroxy-clarithromycin were also within the acceptance ranges, although the confidence intervals for these parameters were not planned to be compared with the acceptance ranges. In the light of the results of the studies reported here it can be concluded that the clarithromycin 250 mg and 500 mg test tablets are bioequivalent to the respective reference formulations.

Adolescent↗
PubMed2004

Clarithromycin suspension: bioequivalence studies on two different strengths.

Two studies were performed in different groups of volunteers, with the aim to prove the bioequivalence of test (Klaromin) and reference clarithromycin (CAS 81103-11-9) suspensions containing in 5 mL either 125 mg (study 1) or 250 mg (study 2) of the drug, administered as an oral dose of 10 mL. Each study was conducted according to an open, randomized, single-dose, two-period cross-over design in healthy volunteers with a wash-out period from 7 to 14 days. Blood samples were taken up to 24 h in both studies, and concentrations of clarithromycin and its principal active 14-hydroxy metabolite were determined by HPLC. In the first study, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of clarithromycin were between 0.84 and 1.03 (AUC0-t) and between 0.89 and 1.03 (Cmax). In the second study, i.e. after administration of clarithromycin suspension 250mg/5mL, the 90% confidence interval for intra-individual ratios of AUC0-inf and Cmax of clarithromycin were between 1.01 and 1.17 (AUC0-inf) and between 1.01 and 1.16 (Cmax). All these values were within the acceptance ranges for bioequivalence studies. In both studies, the 90% confidence interval for intra-individual ratios of AUC0-inf and Cmax of 14-hydroxy-clarithromycin were also within the acceptance ranges. In the light of the results of the studies reported here it can be concluded that the clarithromycin test formulations are bioequivalent to the respective reference formulations, i.e. suspensions containing 125 mg/5 mL and 250 mg/5 mL of the drug.

Adolescent↗
PubMed1999

Clarithromycin for experimental Staphylococcus aureus keratitis.

PURPOSE: Clarithromycin, a macrolide antibiotic not previously tested against the common causes of bacterial keratitis, was analyzed for its effectiveness in reducing the number of viable bacteria in a Staphylococcus keratitis model. An in vivo comparison of the effectiveness of clarithromycin to erythromycin, minocycline, and tetracycline for three strains of Staphylococcus aureus was done. METHODS: Rabbit eyes were intrastromally injected with 100 colony forming units of one of three strains of S. aureus. Two strains were methicillin-sensitive (ATCC 25923 and MSSA 309) and one strain methicillin-resistant (COL). Eyes were treated every 30 minutes with 0.3% clarithromycin, erythromycin, tetracycline, or minocycline from 4 to 9 hours postinfection. The number of colony forming units (CFU) per cornea in all eyes was determined at 10 hours postinfection. RESULTS: Vehicle-treated and untreated eyes (controls) contained over 6 logs of CFU per cornea, a value significantly higher than any of the antibiotic-treated eyes (P < or = 0.0001). Clarithromycin or erythromycin therapy significantly decreased the number of CFU per cornea by approximately 5 logs in the eyes infected with the methicillin-sensitive strains and by approximately 4 logs in the eyes infected with the methicillin-resistant strain. Tetracycline and minocycline were also successful in treating these strains, but overall showed less effectiveness than clarithromycin and erythromycin. CONCLUSIONS: Clarithromycin proved to be an effective ocular medication for the therapy of experimental S. aureus keratitis. The effectiveness of clarithromycin in this model and its known effectiveness for a variety of bacterial pathogens suggests a role for this drug as a useful ocular antibiotic.

Animals↗
PubMed2000

Clarithromycin or rifabutin alone or in combination for primary prophylaxis of Mycobacterium avium complex disease in patients with AIDS: A randomized, double-blind, placebo-controlled trial. The AIDS Clinical Trials Group 196/Terry Beirn Community Programs for Clinical Research on AIDS 009 Protocol Team.

The efficacy and safety of clarithromycin and rifabutin alone and in combination for prevention of Mycobacterium avium complex (MAC) disease were compared in 1178 patients with AIDS who had < or =100 CD4 T cells/microL in a randomized, double-blind, placebo-controlled trial. MAC disease occurred in 9%, 15%, and 7% of those randomized to clarithromycin or rifabutin alone or in combination, respectively; time-adjusted event rates per 100 patient-years (95% confidence interval [CI]) were 6.3 (4.2-8.3), 10.5 (7.8-13.2), and 4. 7 (2.9-6.5). Risk of MAC disease was reduced by 44% with clarithromycin (risk ratio [RR], 0.56; 95% CI, 0.37-0.84; P=.005) and by 57% with combination therapy (RR, 0.43; 95% CI, 0.27-0.69; P=. 0003), versus rifabutin. Combination therapy was not more effective than clarithromycin (RR, 0.79; 95% CI, 0.48-1.31; P=.36). Of those in whom clarithromycin or combination therapy failed, 29% and 27% of MAC isolates, respectively, were resistant to clarithromycin. There were no survival differences. Clarithromycin and combination therapy were more effective than rifabutin for prevention of MAC disease, but combination therapy was associated with more adverse effects (31%; P<.001).

AIDS-Related Opportunistic Infections↗
PubMed1991

A comparison of clarithromycin with ampicillin in the treatment of outpatients with acute bacterial exacerbation of chronic bronchitis.

One hundred and twenty-five outpatients with clinical symptoms of an acute bacterial exacerbation of chronic bronchitis were enrolled in a multicentre, double-blind, randomized clinical trial to compare the efficacy and safety of oral clarithromycin and ampicillin. Only those patients presenting with pathogens cultured from pre-treatment specimens susceptible to both study drugs were included in the study; beta-lactamase producing strains were excluded. Sixty patients received clarithromycin 250 mg 12-hourly and 65 had ampicillin 250 mg 6-hourly for 7-14 days. Clinical and bacteriological evaluations were performed pre-treatment, during treatment, and post-treatment within 48 h of cessation of therapy. All adverse events reported were evaluated. Twenty patients from the clarithromycin group and 24 from the ampicillin group were withdrawn from the study when no pathogen was isolated from the pre-treatment specimens. Twenty-eight patients who received clarithromycin and 23 who received ampicillin were evaluable for clinical and bacteriological efficacy. Both treatment groups were similar with respect to clinical and bacteriological response rates. The clinical cure rate for clarithromycin was 96% (27/28) compared with 91% (21/23) for the ampicillin group. Clarithromycin achieved a bacteriological cure rate of 96% (27/28) compared with 100% (23/23) for the ampicillin group. Adverse events, which were generally mild and associated with the digestive system, were reported by 11.7% of patients receiving clarithromycin and 1.5% of patients receiving ampicillin. Adverse events caused two patients in each group to discontinue treatment. Laboratory profiles for both groups were unremarkable throughout treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Acquired resistance in Mycobacterium avium complex strains isolated from AIDS patients and beige mice during treatment with clarithromycin.

Clarithromycin has been reported to select clarithromycin resistant mutants of Mycobacterium avium complex (MAC) during treatment with clarithromycin in AIDS patients and beige mice. We selected resistant mutants in vitro at a frequency of 5 x 10(-9). Clarithromycin resistant strains of MAC isolated in AIDS patients and beige mice as well as derivatives selected in vitro had a unique pattern of acquired cross-resistance to macrolides and related antibiotics. In contrast, the pattern of resistance to non-macrolide antibiotics remained unchanged in clarithromycin resistant strains. A dramatic decrease in ribosome affinity for clarithromycin and erythromycin was found in clarithromycin resistant strains, but no mutation was found in the peptidyl domain of the 23S rRNA, indicating that another ribosomal modification is involved.

Acquired Immunodeficiency Syndrome↗
PubMed1995

A comparison of 5 days of dirithromycin and 7 days of clarithromycin in acute bacterial exacerbation of chronic bronchitis.

The safety and efficacy of dirithromycin and clarithromycin were compared in a single-blind, multicentre study of patients with acute bacterial exacerbation of chronic bronchitis (AECB). Patients received either dirithromycin, 500 mg once daily for 5 days, or clarithromycin, 250 mg twice daily for 7 days. A total of 212 patients entered the study, of whom 191 qualified for efficacy analysis. Favourable post-therapy clinical and bacteriological response rates for qualified patients (95 dirithromycin and 96 clarithromycin) were similar: 89.5% and 68.8% for dirithromycin vs 94.8% and 71.9% for clarithromycin. At late post-therapy evaluation, favourable clinical and bacteriological response rates were achieved in 98.8% and 96.2% of dirithromycin patients and 95.3% and 93.3% of clarithromycin patients, respectively. These differences were neither statistically nor clinically significantly different. Both drugs had similar efficacy against Haemophilus influenzae and both were well tolerated. Dirithromycin, administered as a single daily dose for just 5 days resulted in complete compliance in all but four patients. In clarithromycin-treated patients, requiring a 7-day course of twice-daily treatment, compliance was less satisfactory, with 12 patients failing to comply, though the between-group difference was not statistically significant. It can be concluded that 5 days of dirithromycin, 500 mg once daily is as safe and effective as 7 days of clarithromycin, 250 mg, twice daily in the treatment of AECB.

Acute Disease↗
PubMed1997

The stability of amoxycillin, clarithromycin and metronidazole in gastric juice: relevance to the treatment of Helicobacter pylori infection.

Although omeprazole is an important component in anti-Helicobacter pylori therapeutic regimes using clarithromycin, amoxycillin and metronidazole, the mechanism by which it enhances antimicrobial action is unknown. One potential explanation for this effect is increased antibiotic chemical stability resulting from gastric pH changes induced by co-administration of omeprazole. The chemical stability of clarithromycin, amoxycillin and metronidazole was investigated in aqueous solutions and in human gastric juice collected before and after a 7-day course of omeprazole. Amoxycillin, clarithromycin and metronidazole were prepared in buffered aqueous solutions of pH 1.0 to 8.0 and in gastric juice of pH 2.0 and 7.0. The gastric juice samples were obtained from fasted H. pylori-negative volunteers before and after they had received a 7-day course of omeprazole. All the samples were incubated at 37 degrees C and analysed at intervals by HPLC. Amoxycillin, clarithromycin and metronidazole were stable in aqueous solutions of pH 4.0-7.0, pH 5.0-8.0 and pH 2.0-7.0, respectively. At pH 2.0, the degradation half-lives were 19.0 +/- 0.2 h, 1.3 +/- 0.05 h and 2200 +/- 1100 h, respectively. In gastric juice samples of pH 2.0, the degradation half-lives were 15.2 +/- 0.3 h, 1.0 +/- 0.04 h and > or = 800 h, respectively. The half-lives of the drugs in the gastric juice samples of pH 7.0 were all > 68 h. The co-administration of omeprazole with amoxycillin or clarithromycin is likely to increase the chemical stability of amoxycillin and clarithromycin in gastric juice. Clarithromycin degrades rapidly at normal gastric pH (1.0-2.0) but amoxycillin and metronidazole are sufficiently stable at this pH to maintain an antibacterial concentration in the stomach.

Amoxicillin↗