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PubMedDate not supplied

A comparative study of clarithromycin modified release and amoxicillin/clavulanic acid in the treatment of acute exacerbation of chronic bronchitis.

This phase III, investigator-blind, randomized, parallel-group study compared the efficacy and tolerability of clarithromycin modified release (MR) with those of amoxicillin/clavulanic acid in 250 adult outpatients with acute exacerbationof chronic bronchitis (AECB). Patients received either clarithromycin MR 500 mg once daily or amoxicillin/clavulanic acid 500 mg/125 mg three times daily for 7 days. Primary endpoints were sponsor-defined clinical response and pathogen outcome at the end of treatment. Secondary endpoints were sponsor-defined clinical response and pathogen outcome at study end, investigator-defined clinical response at end of treatment and end of study, resolution or improvement of signs and symptoms, eradication of baseline pathogens, serologic outcome for atypical pathogens, and occurrence of reinfection and superinfection. Adverse events and compliance were also evaluated. Clinical and bacteriologic outcomes with both treatments for all endpoints were statistically equivalent, as were total adverse events, although the incidences of digestive disturbances (13% vs 4%) and discontinuations due to adverse events (8 vs 2 patients; P < or =.05) were significantly higher with amoxicillin/clavulanic acid. Ninety-five percent of patients receiving clarithromycin MR and 80% receiving amoxicillin/clavulanic acid were 100% compliant with medication (P < or =.05). Clarithromycin MR and amoxicillin/clavulanic acid are both well tolerated and effective as therapy for AECB; however, clarithromycin produced fewer side effects and discontinuations and higher compliance rates.

Amoxicillin-Potassium Clavulanate Combination↗
PubMed2002

Effect of 3 months of antimicrobial treatment with clarithromycin in acute non-q-wave coronary syndrome.

BACKGROUND: Coronary artery disease, an inflammatory disease, may be caused by infection. We investigated whether the antibiotic clarithromycin would reduce morbidity and mortality in patients with acute non-Q-wave coronary syndrome. METHODS AND RESULTS: Altogether, 148 patients with acute non-Q-wave infarction or unstable angina were randomly assigned to receive double-blind treatment with either clarithromycin or placebo for 3 months. The primary end point was a composite of death, myocardial infarction, or unstable angina during treatment; the secondary end point was occurrence of any cardiovascular event during the entire follow-up period (average 555 days, range 138 to 924 days). There was a trend toward fewer patients meeting primary end-point criteria in the clarithromycin group than in the placebo group (11 versus 19 patients, respectively; risk ratio 0.54, 95% CI 0.25 to 1.14; P=0.10). By the end of the entire follow-up, 16 patients in the clarithromycin group and 27 in the placebo group had experienced a cardiovascular event (risk ratio 0.49, 95% CI 0.26 to 0.92; P=0.03). CONCLUSIONS: Clarithromycin appears to reduce the risk of ischemic cardiovascular events in patients presenting with acute non-Q-wave infarction or unstable angina. No signs of this effect diminishing were observed during follow-up.

Adolescent↗
PubMed2006

The effect of ciprofloxacin and clarithromycin on sildenafil oral bioavailability in human volunteers.

Sildenafil is the first oral therapeutic agent for the management of male erectile dysfunction. Its oral bioavailability is only 40% due to extensive presystemic elimination, mainly by CYP3A4. This study examined the effect of coadministration of ciprofloxacin or clarithromycin, which inhibit CYP3A4, on the bioavailability and pharmacokinetics of sildenafil. Twelve healthy male volunteers received sildenafil alone or after pretreatment with the inhibitors in a balanced three-way crossover design. The pharmacokinetic analysis showed that ciprofloxacin coadministration with sildenafil significantly increased the AUC from 1407 +/- 380 to 2986 +/- 917 microg h/l (90% confidence interval 119%-159%) and the Cmax from 287 +/- 67 to 623 +/- 192 microg/l (90% confidence interval 127%-152%). Similarly, clarithromycin coadministration increased sildenafil AUC from 1407 +/- 380 to 3209 +/- 762 microg h/l (90% confidence interval 127%-161%) and Cmax from 287 +/- 67 to 694 +/- 259 microg/l (90% confidence interval 132%-157%). Ciprofloxacin coadministration and clarithromycin coadministration with sildenafil did not affect the rate of sildenafil absorption significantly. These results indicate that coadministration of ciprofloxacin and clarithromycin significantly increased sildenafil bioavailability which can be attributed to the inhibitory effect of ciprofloxacin and clarithromycin on CYP3A4. Dose adjustment of sildenafil is thus necessary when administered with such drugs.

Administration, Oral↗
PubMed1992

Clarithromycin pharmacokinetics in healthy young and elderly volunteers.

The pharmacokinetics of clarithromycin and its active 14(R)-hydroxy metabolite were assessed in 12 healthy young and 12 healthy elderly volunteers after oral administration of a multiple dose regimen of oral clarithromycin (500 mg every 12 hours for 5 doses). Plasma and urine clarithromycin and 14(R)-hydroxyclarithromycin concentrations were determined using high-performance liquid chromatography. The elderly subjects exhibited significantly elevated clarithromycin peak (Cmax) and trough (Cmin) plasma concentrations and area under the plasma concentration-time curve (AUC) compared with young subjects. In addition, the elderly group exhibited a significantly reduced apparent total body clearance (300 +/- 97 versus 476 +/- 112 mL/min, respectively) and renal clearance (CLR) (84 +/- 31 versus 168 +/- 35 mL/min, respectively). Similar results were noted for the 14(R)-hydroxy metabolite, with significantly elevated Cmax, Cmin, and AUC and reduced CLR in the elderly compared with the young group. Because the differences in parent and metabolite pharmacokinetic parameters were small and the increase in circulating drug concentrations was well tolerated (no increase in incidence or severity of adverse events), adjustments in clarithromycin dosing regimens may not be necessary solely on the basis of age.

Administration, Oral↗
PubMedDate not supplied

Accumulation of clarithromycin in macrophages infected with Mycobacterium avium.

Clarithromycin is known to accumulate in polymorphonuclear leukocytes, but no accumulation studies with macrophages have been reported. We exposed J774 macrophages, grown for 4-6 days, to clarithromycin 3.0 micrograms/ml for 2 hours. The cells were separated from the extracellular fluid, and the concentration of clarithromycin was determined in an agar diffusion bioassay. The accumulation of clarithromycin was 15.8-fold greater in the cells than it was in the extracellular fluid when the test was performed with noninfected cells, and 17.3-fold greater for cells infected with Mycobacterium avium. However, the ratio was substantially lower, only 3.7 for dead macrophages, suggesting that intracellular accumulation is probably an active process. These data may clarify the nature of the activity of clarithromycin against M. avium in macrophages.

Biological Assay↗
PubMed2000

Clarithromycin attenuates cyclophosphamide-induced mucositis in mice.

No universally recognized agent is available for prophylaxis or therapy of mucositis induced by chemotherapy or chemo-radiotherapy. The effect of clarithromycin on the severity of mucositis induced by cyclophosphamide was investigated using a mouse model. Four cross-sections of small intestine (levels A, B, C, and D) were taken at equivalent intervals at day 5 after cyclophosphamide (400 mg kg(-1)) administration. The sections were stained with haematoxylin and eosin, and were graded for the degree of mucositis histologically. At section level B, the number of mice with no mucositis (grade 0) in the clarithromycin group was significantly greater than that in the ceftriaxone group (P<0.05). At levels B and C, the number of mice with no mucositis (grade 0) in the clarithromycin group was significantly greater than that in the normal saline (NS) group (P<0.05). At level C, the number of mice with grade 2 mucositis in the ceftriaxone group was significantly greater than that in the NS group (P<0.05). When the number of sections at all levels were analyzed together, the number of mice with no mucositis (grade 0) in the clarithromycin group was significantly greater than that in the ceftriaxone and NS groups (P<0.05). The present observation suggests that clarithromycin and ceftriaxone attenuates and aggravates cyclophosphamide-induced mucositis. It prompts clinical trials in bone marrow transplant (BMT) recipients receiving cyclophosphamide for conditioning, and reconsideration in the use of ceftriaxone in the treatment of neutropenic fever in BMT recipients.

Animals↗
PubMed2000

Comparison of the efficacy of 400mg and 800mg of clarithromycin used with lansoprazole and amoxicillin in eradication regimens for Helicobacter pylori infection in a Japanese population.

We conducted a randomized prospective comparative study to determine whether a 1-week lansoprazole-amoxicillin-clarithromycin (LAC) regimen with 800 mg of clarithromycin a day was more effective such a regimen with 400 mg daily in the Japanese population. One hundred and seventy-five Helicobacter pylori-positive patients were randomly assigned to receive one of two different 7-day regimens, one with clarithromycin 400 mg (LAC 400 regimen) and the other with clarithromycin 800 mg (LAC 800 regimen). The cure rates for both regimens were similar, although adverse effects were significantly more frequent in the LAC 800 regimen, suggesting that 400 mg of clarithromycin may be sufficient in our patient population.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2005

Helicobacter pylori infection rate in patients with nontuberculous mycobacteriosis who are on longterm combination chemotherapy of clarithromycin and rifampicin.

Clarithromycin resistance in Helicobacter pylori has increased the incidence of eradication failure. Clarithromycin is a key drug in the current treatment regimens for H. pylori infection, and it is also used for nontuberculous mycobacteriosis (NTM). The rate of H. pylori infection in 15 patients with NTM who were on longterm clarithromycin, rifampicin, and other drug therapy was examined, using the [(13)C] urea breath test. H. pylori was detected in 5 of the 15 patients (33.3%), which was significantly lower than the prevalence of H. pyloriin subjects who had routine upper gastrointestinal endoscopy in Japan (P = 0.0006). Thus, H. pylori resistance to clarithromycin is suggested to be low in patients with longterm administration, and the possibility exists of a combination of clarithromycin and rifampicin as a second-line therapy for the eradiation of H. pylori.

Aged↗
PubMed1996

Antimicrobial susceptibility testing of Helicobacter pylori. Comparison of E-test, broth microdilution, and disk diffusion for ampicillin, clarithromycin, and metronidazole.

The optimal method for the determination of the minimum inhibitory concentration (MIC) of antimicrobials against Helicobacter pylori has not been established. The epsilometer agar diffusion gradient test (E-Test; AB Biodisk, Solna, Sweden) was compared with broth microdilution, the reference method, and disk diffusion for the antimicrobial susceptibility testing of 122 clinical isolates of H. pylori to ampicillin, clarithromycin, and metronidazole. Isolates were considered to be resistant when the MIC values was > 8 micrograms/ml for either ampicillin or metronidazole and > 2 micrograms/ml for clarithromycin. For an individual isolate, the MICs for ampicillin and clarithromycin determined by broth microdilution and the E-test were highly reproducible, with replicate results being within +/- 1 log2 dilution. The correlation between the MICs determined by E-test and broth microdilution was excellent for both ampicillin and clarithromycin (90.1% and 88.5% were within +/- log2 dilution, and 98.3% and 96.7% of the values were within +/- 2 log2 dilution, respectively). In no instance did the interpretation of "sensitive" or "resistant" differ. Conversely, only 70.5% of the E-test results of metronidazole were within +/- 1 log2 dilution of the broth microdilution results. In addition, 15 (12.3%) of the H. pylori isolates interpreted as resistant by the E-test were sensitive by the broth microdilution method. All discrepancies occurred when the E-test MIC values fell between 8 and 32 micrograms/ml. The results of the ampicillin and clarithromycin disk diffusion assay correlated 100% with the results of the broth microdilution. However, these data suggest that when the E-test MIC results of metronidazole yield values between 8 and 32 micrograms/ml, the MIC should be reevaluated by another method.

Ampicillin↗
PubMed2004

The effect of clarithromycin, fluconazole, and rifabutin on dapsone hydroxylamine formation in individuals with human immunodeficiency virus infection (AACTG 283).

BACKGROUND: Dapsone hydroxylamine formation is thought to be the cause of the high rates of adverse reactions to dapsone in human immunodeficiency virus (HIV)-infected individuals. Therefore we studied the effect of the commonly coadministered drugs fluconazole, clarithromycin, and rifabutin on hydroxylamine formation in individuals with HIV infection. METHODS: HIV-infected subjects (CD4 + > or =200 cells/mm 3 ) were enrolled in a 2-part (A or B) open-label drug interaction study. In part A, subjects (n = 12) received dapsone (100-mg tablet once daily) alone for 2 weeks and then, in a randomly assigned order, received dapsone and either fluconazole (200 mg daily), rifabutin (300 mg daily), or fluconazole plus rifabutin, each for a 2-week period. Part B (n = 11) was identical to part A except that clarithromycin (500 mg twice daily) was substituted for rifabutin. On the last study day of each 2-week period, plasma and urine were collected over ascorbic acid for 24 hours. RESULTS: In part A, fluconazole decreased the area under the plasma concentration-time curve, percent of dose excreted in 24-hour urine, and formation clearance of the hydroxylamine by 49%, 53%, and 55% (n = 12, P < .05), respectively. This inhibition of in vivo hydroxylamine formation was quantitatively consistent with that predicted from human liver microsomal experiments. Rifabutin had no effect on hydroxylamine area under the plasma concentration-time curve or percent excreted in 24-hour urine but increased formation clearance of the hydroxylamine by 92% (n = 12, P < .05). Dapsone clearance was increased by rifabutin or rifabutin plus fluconazole (67% and 38%, respectively) (n = 12, P < .05) but was unaffected by fluconazole or clarithromycin. In part B, hydroxylamine production was unaffected by clarithromycin but was affected by fluconazole in a manner identical to that in part A. CONCLUSIONS: On the basis of these data and with the assumption that the exposure to the hydroxylamine is a determinant of dapsone toxicity, we predict that coadministration of fluconazole should decrease the rate of adverse reactions to dapsone in persons with HIV infection but that rifabutin and clarithromycin will have no effect. When dapsone is given in combination with rifabutin, dapsone dosage adjustment may be necessary in light of the increase in dapsone clearance.

Adult↗
PubMed2004

Clarithromycin in 2003: sustained efficacy and safety in an era of rising antibiotic resistance.

Data from surveillance studies show increasing prevalence of respiratory pathogens resistant to commonly used antibiotics. Thus, a Medline search was conducted to identify studies of clarithromycin, especially those addressing macrolide resistance. Changing trends of in vitro susceptibility have not affected clinical efficacy with clarithromycin. Over the last 12 years, clarithromycin study results have shown consistent rates of clinical cure and bacteriological eradication, which are similar to those observed with comparator agents. The incidence of clarithromycin treatment failure in patients infected with Streptococcus pneumoniae is substantially less than that predicted by macrolide resistance rates from surveillance programmes. In summary, despite widespread use since its introduction, clarithromycin remains active both in vitro and in vivo against clinically relevant respiratory tract pathogens.

Anti-Bacterial Agents↗
PubMed2005

Clarithromycin co-administered with amikacin attenuates systemic inflammation in experimental sepsis with Escherichia coli.

To assess the efficacy of clarithromycin as an immunomodulator in experimental sepsis with Escherichia coli, acute pyelonephritis was induced after ligation of the right ureter and injection of the test isolate into the renal pelvis in 40 rabbits. Four groups of treatment were applied with administration of therapy on advent of sepsis-associated pulmonary oedema, as follows: A: controls; B: clarithromycin; C: amikacin, D: both agents. Survival was recorded along with estimation of serum levels of endotoxins (LPS), of tumour necrosis factor-alpha (TNFalpha), malondialdehyde (MDA) and of bacterial counts. Mean survival of groups A, B, C and D was 2.51, 7.60, 10.25 and 11.40 days, respectively. Serum levels of TNFalpha and of MDA of group A increased over-time. Pulmonary oedema at 6 h after bacterial challenge was accompanied by increase of TNFalpha and MDA; administration of clarithromycin decreased their values. It is concluded that intravenous clarithromycin might constitute a promising immunomodulatory agent for the management of sepsis since its efficacy was proved after administration on presentation of sepsis-associated pulmonary oedema. The presented findings emphasise the need for further clinical research of the use of clarithromycin for the therapy of Gram-negative sepsis.

Acute Disease↗
PubMed2006

Impact of rifampicin addition to clarithromycin in Legionella pneumophila pneumonia.

We evaluated the effectiveness and safety of rifampicin addition to clarithromycin in the treatment of Legionnaires' disease. An observational cohort study was conducted on patients assigned to a Legionnaires' disease outbreak. Of 32 patients with confirmed Legionella pneumonia, 11 received clarithromycin monotherapy and 21 received combination therapy of clarithromycin with rifampicin. Both groups had similar baseline characteristics and all patients were cured. Patients who received rifampicin had a 50% longer length of stay (P=0.035) and a trend towards higher bilirubin levels (P=0.053). Length of stay was directly correlated with the duration of rifampicin treatment (P=0.001). Combination therapy of clarithromycin and rifampicin had no additional benefit compared with clarithromycin monotherapy and could prolong the length of stay owing to possible negative drug interactions that could also affect other antibiotics.

Aged↗
PubMed2004

Pharmacokinetic interactions between omeprazole/pantoprazole and clarithromycin in health volunteers.

The association omeprazole/clarithromycin is of current wide use in the treatment of Helicobacter pylori associated gastroduodenal ulcer. This combination may result in increased levels of omeprazole with potential interactions with commonly associated drugs. Kinetic/metabolic changes occurring after omeprazole/clarithromycin were compared to those occurring after pantoprazole/clarithromycin in healthy volunteers. Eight healthy volunteers, all males, age 25-34 years, all EM for CYP2C19, participated in a randomized, double blind crossover study in two periods of 7 days, separated by a 14-day washout. In each treatment period, subjects took either omeprazole 20mg b.i.d. together with clarithromycin 500 mg b.i.d., or pantoprazole 40 mg b.i.d. with the same dose of the antibiotic. The pharmacokinetic parameters of omeprazole and pantoprazole were compared to those after intake of both agents alone. Kinetics of unchanged clarithromycin was evaluated at the end of the two periods. The mean value of the area under the plasma concentration versus time curve (AUC) of unchanged omeprazole increased almost two-fold after concomitant administration of clarithromycin; the average 5-OH-omeprazole AUC was instead significantly reduced by 42%. Omeprazole clearance and volume of distribution were reduced significantly by 75 and 56%, respectively, after administration of the drug with clarithromicyn. No significant changes of the kinetic of pantoprazole and metabolites were observed. Kinetics of clarithromycin did not differ after the two associated treatments. The administration of clarithromycin with two different proton pump inhibitors indicates that the antibiotic can markedly increase omeprazole, not pantoprazole, levels. This observation may result in a better therapeutic response to omeprazole, but it may also potentially affect either the metabolism of CYP3A4 substrates or interfere with the absorption of drugs requiring an intact gastric digestion system.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2002

A prospective, double-blind, multicenter study comparing clarithromycin extended-release with trovafloxacin in patients with community-acquired pneumonia.

BACKGROUND: Treatment guidelines for community-acquired pneumonia (CAP) generally include use of a macrolide, a fluoroquinolone, or doxycycline, although there is some debate concerning the use of a fluoroquinolone. OBJECTIVE: The efficacy and tolerability of a new once-daily, extended-release (ER) formulation of clarithromycin were compared with those of a fluoroquinolone, trovafloxacin, in the treatment of patients with CAP. METHODS: This was a prospective, multicenter, double-blind, double-dummy, parallel-group trial in which outpatients were randomized to receive 7 days of once-daily treatment with either clarithromycin ER (two 500-mg tablets) or trovafloxacin (200 mg). Eligible patients were > or = 18 years old with signs and symptoms of pneumonia, radiologic evidence of an acute infiltrate, and mild to moderate infection, as classified by the investigator. RESULTS: One hundred seventy-six patients were randomized to study treatment. They were primarily white (88%) and equally distributed between the sexes (52% female). Their mean (+/-SD) age was 47.5 +/- 16.2 years. Results were similar between treatment groups in rates of clinical cure, microbiologic cure, bacteriologic eradication, and radiologic success at the test-of-cure visit (14-21 days posttreatment) for both the per-protocol and intent-to-treat analyses. Among clinically evaluable patients, clinical cure rates for clarithromycin ER and trovafloxacin were 87% (74/85) and 95% (63/66), respectively, and radiologic success rates were 95% (80/84) and 95% (63/66), respectively. There were no statistically significant differences between groups. In clinically and microbiologically evaluable patients, overall bacteriologic eradication rates were 89% (85/95) for clarithromycin ER and 96% (64/67) for trovafloxacin, with no significant differences between groups. Both antibiotics demonstrated high eradication rates against target microorganisms. There were no clinically meaningful differences in the incidence of specific drug-related adverse events. The majority of drug-related adverse events (>90%) were considered mild or moderate and resolved without the need for additional treatment. CONCLUSIONS: Although the study was prematurely terminated, resulting in inadequate power to demonstrate equivalence, once-daily clarithromycin ER was effective and well tolerated in the treatment of ambulatory adult (age > or = 18 years) outpatients with CAP.

Adult↗
PubMed1999

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.

Animals↗
PubMed1998

Evaluation of a disk diffusion method for determining susceptibility of Mycobacterium avium complex to clarithromycin.

We evaluated an agar disk diffusion method for determining the susceptibility of Mycobacterium avium complex to clarithromycin. Isolates were inoculated onto the surface of a Middlebrook 7H11 plate, followed by the application of a 15-microgram clarithromycin disk. Zone sizes were read after 5-7 days of incubation. Zone sizes had a bimodal distribution; 40 isolates (10%) had no zone of inhibition, whereas the zone sizes for the remaining isolates ranged from 11 to 60 mm. Most isolates (37/40) having no zone of inhibition came from patients who had been treated previously with clarithromycin. Fifty-one isolates were also tested for clarithromycin susceptibility using a microdilution broth method. Defining susceptibility as a zone size of > 10 mm, disk diffusion test results agreed with the results by the microdilution broth method for 50 of 51 (98%) isolates tested by both methods. Agar disk diffusion is a promising method for the determination of clarithromycin susceptibility testing for M. avium complex.

Animals↗
PubMed1998

AIDS-related Mycobacterium kansasii infection with initial resistance to clarithromycin.

Clarithromycin is a promising drug for the treatment of Mycobacterium kansasii infection. We report a patient with AIDS and severe M. kansasii infection who had previously received a short course of clarithromycin for sinusitis. He had clinical failure of treatment using clarithromycin plus ethambutol, and the initial isolate was found to be highly resistant to clarithromycin. Nucleotide sequencing of the 23S rRNA gene of this isolate demonstrated a single base mutation at position 2058, the same as that found in clarithromycin-resistant Mycobacterium avium.

AIDS-Related Opportunistic Infections↗