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PubMed2000

Postmarketing surveillance of medications and pregnancy outcomes: clarithromycin and birth malformations.

PURPOSE: This retrospective surveillance study used linked administrative claims data and medical records to determine the rate and types of birth malformations in infants born to women exposed to the antibiotic, clarithromycin (Biaxin), during the first trimester of pregnancy. METHODS: Pharmacy and hospital claims from eight geographically diverse health plans were used to identify women who had a delivery claim within 270 days of a clarithromycin prescription over a 5-year period (1991-1995). Hospital delivery admission medical records for 143 mothers and their 149 infants were abstracted to identify birth malformations. RESULTS: Five infants were identified with major malformations, three with minor malformations, and four with undescended testicles likely to resolve with time. The observed rate of 3.4% (95% CI, 0.5, 6.3) for major malformations was not statistically significantly different compared to an expected rate of 2.8% based on earlier national data. There was no consistency across types of major malformations. CONCLUSIONS: These results provide no evidence that clarithromycin is a likely major teratogen in humans. Use of claims data is one way to evaluate quickly and efficiently the safety of prescription medications in humans during pregnancy, especially when both exposure and outcome are rare.

Abnormalities, Drug-Induced↗
PubMed2001

Effect of clarithromycin on airway obstruction and inflammatory markers in induced sputum in cystic fibrosis: a pilot study.

To determine whether macrolide antibiotics improve pulmonary function and decrease airway inflammation in cystic fibrosis (CF), we treated 10 patients (females; aged 19-26 years, all colonized with P. aeruginosa, none with atypical Mycobacteria) with 3 weeks of placebo, followed by 6 weeks of clarithromycin (500 mg BID) in a single-blind prospective study. We also determined the safety of sputum induction and the reproducibility of assessing inflammatory markers in induced sputum. Subjects performed spirometry and underwent sputum induction (12-min inhalation of 3% saline) at 3-week intervals. We found that sputum induction was well-tolerated. We also found that the reproducibility was high for neutrophil (PMN) number (R = 0.87, P = 0.009), interleukin (IL)-8 (R = 0.73, P < 0.05, free neutrophil elastase (NE) (R = 0.82, P < 0.05), and myeloperoxidase (MPO) levels (R = 0.86, P < 0.05), but was less so for tumor necrosis factor (TNF)-alpha (R = -0.15, P = 0.7). We found no significant difference in pulmonary function after 6 weeks of treatment with clarithromycin (FEV(1) (% predicted) (mean +/- SEM), 2.2 +/- 0.9 (60 +/- 24%) vs. 2.3 +/- 1 (61 +/- 29%)), and no significant differences in any of the inflammatory indices measured. The median (and range) values before and after treatment for indices of airway inflammation in the induced sputum samples were: for PMNs, 8 (1-326) and 21 (0.2 -175) x 10(6) cells/mL sputum; for IL-8, 156 (24-656) and 202 (16-680) ng/mL; for free NE, 260 (31-1,264) and 237 (49-1,048) microg/mL; for TNF-alpha, 20 (7-128) and 35 (17-87) pg/mL; and for MPO, 169 (13-960) and 195 (14-816) microg/mL. We conclude that clarithromycin is not uniformly effective in improving airway obstruction or in decreasing airway inflammation in patients with CF.

Adult↗
PubMedDate not supplied

In vitro testing of clarithromycin in combination with ethambutol and rifampicin against Mycobacterium avium complex.

The activity of clarithromycin in combination with ethambutol and rifampicin was tested at concentrations achievable in serum against 20 strains of Mycobacterium avium complex. The combination of clarithromycin plus rifampicin showed inhibition of 11 of the strains and bactericidal synergism against seven of the strains. When ethambutol was added, a bactericidal effect was observed against 16 strains. On the basis of these in vitro data it seems that clarithromycin in combination with rifampicin and ethambutol may be a promising drug for the effective treatment of infections caused by M. avium complex.

Clarithromycin↗
PubMed1996

Prevalence of primary Helicobacter pylori resistance to metronidazole and clarithromycin in The Netherlands.

The minimum inhibitory concentrations of metronidazole and clarithromycin were determined for 780 Helicobacter pylori strains collected in 1994 and 1995 from three different regions in The Netherlands. The overall prevalence of primary metronidazole resistance was 17%, with resistance found more frequently in women (24%) than in men (13%). There was no significant difference between the levels of resistance in the three regions. Primary clarithromycin resistance was rare (1%) and relatively infrequent as compared to that found in other countries. Four of the six strains resistant to clarithromycin were also resistant to metronidazole.

Anti-Bacterial Agents↗
PubMed1997

Evaluation of rapid molecular methods for detection of clarithromycin resistance in Helicobacter pylori.

Resistance of Helicobacter pylori to clarithromycin is due to point mutations at position A2143 or A2144 of the rrnH 23S rRNA gene, each mutation creating an additional restriction site for BsaI or MboII. A procedure combining PCR and RFLP analysis was evaluated for detection of these mutations using primers specific for the 23S rRNA gene, and BsaI and MboII enzymes. All clarithromycin-resistant isolates (8/8), as defined by the MIC, were found to be resistant by PCR-RFLP. No clarithromycin-sensitive isolates (14/14) gave a positive reaction.

Anti-Bacterial Agents↗
PubMed1990

In vitro activity of tosufloxacin (A-60969) and clarithromycin (A-56268, TE-031) against resistant Haemophilus influenzae, Streptococcus pneumoniae and Branhamella catarrhalis isolates.

The activity of tosufloxacin (A-60969), a new oral quinolone, and clarithromycin (A-56268, TE-031), a new oral macrolide, was compared in vitro to that of other oral quinolones and beta-lactam antimicrobial agents against clinical isolates of ampicillin and/or chloramphenicol resistant Haemophilus influenzae, penicillin resistant Streptococcus pneumoniae and beta-lactamase producing Branhamella catarrhalis. Results were compared to those for sensitive isolates. Tosufloxacin was the most active compound against Haemophilus influenzae and was more active than ciprofloxacin or ofloxacin against all strains of Streptococcus pneumoniae. Tosufloxacin was also more active than any of the beta-lactam drugs tested against penicillin resistant or relatively penicillin resistant isolates. Clarithromycin was the most active compound tested against both penicillin sensitive and penicillin resistant Streptococcus pneumoniae, and was as active as ciprofloxacin against Branhamella catarrhalis. In view of the favourable in vitro activity against common bacterial respiratory pathogens, tosufloxacin should be considered for clinical trials in adults with respiratory tract infections, while clarithromycin might be useful in treatment of infection with these organisms in all age groups.

4-Quinolones↗
PubMedDate not supplied

A randomized comparison of two clarithromycin doses for treatment of Mycobacterium avium complex infections.

Two dosages of clarithromycin were compared for treatment of disseminated Mycobacterium avium disease of AIDS patients: high-dose (HD): 1,000 mg or 750 mg b.i.d. according to body weight, and low-dose (LD): 1,000 mg or 750 mg q.d. Patients with high probability of M. avium positive blood culture on day 0 received a 42-day clarithromycin treatment with HD (n = 27) or LD (n = 28) at random after stratification according to body weight. Assessment procedures, including quantitative blood cultures, were performed at days 14, 28 and 42. Forty-five patients were eligible for clinical and 28 for bacteriological evaluation. Bacteriological success was observed in 12 HD and 11 LD patients, partial success in one HD and two LD and failure in none of the HD and two LD (p = 0.33). Between days 0 and 42, log decreases in CFU counts/ml were (mean +/- SD) 3.13 +/- 0.82 (HD) and 2.67 +/- 1.8 (LD) (p = 0.38). Fever and night sweats significantly improved similarly in both groups; no change in spleen and liver size was observed on CT scans. Eight patients died during the study but no death was reported as drug related. Sixteen patients (HD = 6, LD = 10) discontinued the treatment because of side effects. A trend towards improved bacteriological effectiveness and reduced tolerance was observed in the HD group but the difference was not significant. With a power of 0.70, no dose effect was demonstrated between the two tested dosages. A daily dose of 1,000 mg clarithromycin was tested in drug combinations to treat disseminated M. avium infection in AIDS patients.

Adolescent↗
PubMedDate not supplied

Anti-inflammatory activity of clarithromycin in adults with chronically inflamed sinus mucosa.

In a phase IV, open-label study, 25 patients with clinically stable chronic sinusitis and persistent maxillary sinus inflammation were treated for 14 days with clarithromycin 500 mg twice daily. Biopsy specimens of the maxillary sinus mucosa were obtained pretreatment and evaluated for macrophages (CD68), eosinophils (MBP), elastase, interleukin-6 (IL-6), IL-8, tumor necrosis factor-alpha (TNF-alpha), and activity of eosinophils (EG2), as well as edema score. Clinical signs and symptoms were assessed pretreatment, at the end of treatment, and 1 and 2 weeks later. Statistically significant reductions (P < or = .05) from pretreatment were observed for all markers of sinus mucosal inflammation, including CD68, EG2, elastase, IL-6, IL-8, TNF-alpha, and edema score, with a trend to decreased total eosinophil count. Improvement was observed for all clinical signs and symptoms of chronic sinusitis--sinus pain, sinus headache, nasal congestion, nasal discharge, and mucopurulent discharge--up to 14 days after the end of treatment. Cultures to evaluate persistent infection with Chlamydia pneumoniae showed negative results. Significant reductions in various markers of sinus mucosal inflammation support the role of clarithromycin in modulating immunologic responses. Improvement of clinical signs and symptoms in patients with chronic inflammatory sinusitis not meeting criteria for known or presumed bacterial infection was also noted up to 2 weeks after completion of a 14-day course of clarithromycin.

Adult↗
PubMed2006

Preparation of prolonged release clarithromycin microparticles for oral use and their in vitro evaluation.

Prolonged release microparticles of clarithromycin (CL) were prepared using Eudragit RL 100 and RS 100 by spray-drying and casting-drying techniques. For the characterization of those microparticles, preparation yield, particle size distribution, X-ray diffraction, thermal behavior, active agent content and in vitro dissolution from the microparticles were performed. HPLC was used for the assay of clarithromycin and the assay method was validated. All the formulations obtained showed prolonged release when compared to pure clarithromycin. Microparticles prepared by spray-drying method had a slower release compared to those of casting-drying method. Spray-drying method seems to be a more suitable method to prepare microparticles for prolongation in release.

Acrylic Resins↗
PubMed2000

Polymorphism of clarithromycin.

It is well recognized that physicochemical properties of drugs are affected by the type of polymorphic crystalline form of drugs. Clarithromycin is known to exist in at least three polymorphic crystalline forms. Since conventional means to obtain the most thermodynamically stable form (Form II) for the antibiotics is known to be associated with a low purity of the stable form, we developed a novel method to improve the purity of the crystalline form by a modification of the preparation process. The new method involved a simple recrystallization of clarithromycin in solvents having 5-12 carbon atoms (e.g., hexane and heptane) or ethers with 4-10 carbon atoms (e.g., isopropyl ether) and, thus, less likely to be associated with the problem in purity of resulting crystal. Differential scanning calorimetry and powder X-ray diffraction were used to compare the crystalline form of the resultant powder with Form II crystal prepared by the conventional method. The crystal prepared by the new method was identical to Form II crystal of the conventional method as evidenced by the lack of the exothermic peak near 110 degrees C in differential calorimetry scan, indicating that Form II crystal could be readily prepared by the new process. Therefore, these data indicated that the improvement in the purity of the Form II crystal for clarithromycin as well as a significant cost reduction is likely by the novel method.

Anti-Bacterial Agents↗
PubMed1998

Cure of Helicobacter pylori infection by omeprazole-clarithromycin-based therapy in non-human primates.

Rhesus monkeys raised in colonies tend to become naturally infected by Helicobacter pylori early in life. Earlier attempts to cure H. pylori infection with a 10-day triple therapy (metronidazole, amoxicillin, and peptobismol) were only partially (60%) successful, probably because of preexisting metronidazole resistance. This study was carried out to determine the efficacy of an alternative clarithromycin-omeprazole-based therapy for curing H. pylori infection in Rhesus monkeys (Macaca mulatta), and to examine histologic and serologic correlates of curing. Five monkeys were endoscoped under ketamine anesthesia. Histology and culture of gastric biopsies and serologic tests demonstrated that they were H. pylori-positive. Two animals had not received prior anti-H. pylori treatment, while three other animals had failed triple therapy and carried metronidazole-resistant H. pylori strains. Quadruple therapy with omeprazole, clarithromycin, amoxicillin, and bismuth subsalicylate was given for 10 days to these five animals. All five animals were cured of the infection, and remained H. pylori-free, based on histology and culture at regular intervals for the 5 months posttherapy during which they were followed. Gastritis scores and anti-H. pylori IgG levels decreased in each animal during this period to levels characteristic of uninfected animals. These results indicate that an omeprazole-clarithromycin-based regimen can cure H. pylori infection in Rhesus monkeys, with resolution of abnormal histology and serologic responses. They suggest that this preclinical animal model is useful for testing new anti-H. pylori therapies.

Amoxicillin↗
PubMed1991

Clarithromycin in the treatment of community-acquired lower respiratory tract infections.

Clarithromycin is a macrolide with in-vitro activity against the organisms usually responsible for community-acquired pneumonia and acute exacerbations of chronic bronchitis. Three double-blind controlled studies each in pneumonia and chronic bronchitis are reviewed. In pneumonia clarithromycin is as effective as erythromycin and in acute-on-chronic bronchitis is as effective as ampicillin. In an open study of 46 patients with pneumonia due to Legionella pneumophila, resolution occurred in 93% with no deaths. The incidence of adverse events was 20% in 3437 patients. These were rarely severe. Clarithromycin is better tolerated than erythromycin and its twice daily dosage is likely to lead to better patient compliance.

Administration, Oral↗
PubMedDate not supplied

Clarithromycin in vitro activity enhanced by its major metabolite, 14-hydroxyclarithromycin.

14-Hydroxyclarithromycin, an active metabolite of clarithromycin, was compared for antimicrobial activity alone and in combination with the parent compound. The 14-hydroxyclarithromycin potency was comparable to that of clarithromycin, but was more active against Haemophilus influenzae (MIC50, 1 microgram/ml). Combination MICs at pharmacokinetic ratios produced end points equal to the most active component of the combination. However, checkerboard MICs and kill-curve studies suggested enhanced interactive effects. Partial synergy and additive interactions were demonstrated in 96% of strains tested with synergy (partial) most often observed among the Enterococcus faecalis, H. influenzae, and staphylococci. To determine the best in vitro test methods for predicting the value of 14-hydroxyclarithromycin, combination disks or ratio MIC tests may not be practical. A modification of the proposed clarithromycin-susceptible breakpoint (less than or equal to 2 micrograms/ml) upward to less than or equal to 4 micrograms/ml (greater than or equal to 14 mm) was suggested to recognize the additional activity contributed by the 14-hydroxy metabolite. This modification should be applied, limited to susceptibility tests of H. influenzae and possibly the enterococci.

Bacteria↗
PubMed1994

Validation of NCCLS macrolide (azithromycin, clarithromycin, and erythromycin) interpretive criteria for Haemophilus influenzae tested with the Haemophilus test medium. National Committee for Clinical Laboratory Standards.

Some recently marketed macrolide antimicrobial agents possess physiochemical, antimicrobial, and pharmacokinetic advantages that enable their wider clinical use against Haemophilus influenzae infections. A five-laboratory study assessed the validity of existing or proposed azithromycin, clarithromycin, and erythromycin interpretive criteria for tests with H. influenzae isolates. National Committee for Clinical Laboratory Standards (NCCLS) methods, criteria, and quality-control guidelines were used. A total of 350 H. influenzae strains were processed, including fresh clinical isolates (250 strains) and replicate tests of 100 stock cultures sampling strains isolated from 1984 to 91. Azithromycin interpretive criteria (susceptible at < or = 4 micrograms/ml, > or = 12 mm) produced a 99.8% absolute agreement between the minimum inhibitory concentrations and disk diffusion results (0.2% false-susceptible error). Clarithromycin breakpoint criteria (susceptible at < or = 8 micrograms/ml, > or = 13 mm; and resistant at > or = 32 micrograms/ml, < or = 10 mm) produced high minor interpretive error, but < or = 1% combined false-susceptible and false-resistant discrepancies. Erythromycin interpretive guidelines were initially proposed for susceptible at < or = 0.5 microgram/ml, > or = 26 mm. This categorizes nearly all H. influenzae strains as resistant to this older macrolide. The NCCLS should consider the proposed erythromycin criteria for publication in appropriate tables, and a class drug should also be selected (azithromycin) that would best predict macrolide-class susceptibility for those agents indicated by the US Food and Drug Administration for H. influenzae infection chemotherapy (azithromycin and clarithromycin). No serious interpretive problems were observed with the current NCCLS criteria using Haemophilus test medium.

Anti-Bacterial Agents↗
PubMed2006

Lung perfusion with clarithromycin ameliorates lung function after cardiopulmonary bypass.

BACKGROUND: Macrolides antibiotics may affect neutrophil functions that correlate with the inflammation induced by cardiopulmonary bypass. Our study observed the protective effect of clarithromycin on inflammatory lung injury after cardiopulmonary bypass. METHODS: Twelve adult sheep were randomly divided into two groups. After cardiopulmonary bypass was established, the lung was perfused through the pulmonary artery with either dextran solution (30 mL/kg) in the control group (n = 6) or dextran solution added to clarithromycin (10 mg/kg) in the experimental group (n = 6). Bypass was withdrawn after 90 minutes. Pulmonary function was determined and inflammatory factors were analyzed. Apoptotic neutrophils in the lung were assayed and lung biopsies were also performed. RESULTS: Pulmonary vascular resistance (102.2 +/- 14.0 dyne.s.cm(-5)) was lower in the experimental group compared with the control group (202.6 +/- 47.3 dyne.s.cm(-5), p < 0.01) whereas the oxygen index was higher in the experimental group (p < 0.05). Plasma myeloperoxidase in the experimental group (0.015 +/- 0.006 U/L) was lower than that in the control group (0.029 +/- 0.007 U/L, p < 0.01). Plasma interlukin-8 (0.18 +/- 0.04 ug/L) and tumor necrosis factor (1.00 +/- 0.13 ug/L) in the experimental group were lower than in the control group (0.39 +/- 0.09 ug/L, 1.55 +/- 0.35 ug/L, p < 0.01). Histologic analyses showed intra-alveolar hemorrhage and neutrophil accumulation in the control group, whereas there were no significant changes in the experimental group. The apoptosis rate of accumulated neutrophils was significantly lower in the control group (p < 0.01). CONCLUSIONS: Lung perfusion with hypothermic protective solution containing clarithromycin distinctly inhibits inflammatory responses caused by cardiopulmonary bypass and ameliorates lung function.

Animals↗
PubMed2006

Degradation of macrolide antibiotics by ozone: a mechanistic case study with clarithromycin.

Macrolide antibiotics are widely used (in the order of 1g per person per year). They pass the body largely unchanged and are also not degraded in wastewater treatment plants. With not too much effort, they may be eliminated from their effluents by ozonation. The macrolide antibiotics have all a dimethylamino group at one of the carbohydrate residues in common. This functional group is the target of the ozone reaction, and clarithromycin has been selected here for a more detailed study. Since only the free amine reacts with ozone, the rate of reaction is pH dependent (at pH 7: k = 4 x 10(4) M(-1) s(-1)). In analogy to the ozonolysis of trimethylamine, the main reaction is a transfer of an O-atom yielding the N-oxide (identified by HPLC/MS-MS). A minor product (10%, based on formaldehyde yields) is demethylated clarithromycin (identified by HPLC/MS-MS). The dimethylamino group is thought to be essential for the binding of the macrolide antibiotics to their target. As a consequence, chemical changes of this functional group, notably the formation of the N-oxide that is no longer a proton acceptor, inactivates these drugs as assayed by the suppression of the growth of Pseudomonas putida. This is most important for wastewater treatment, as mineralization of clarithromycin by ozone would require 100 times as much ozone.

Anti-Bacterial Agents↗
PubMed2006

Influences of proinflammatory and anti-inflammatory cytokine polymorphisms on eradication rates of clarithromycin-sensitive strains of Helicobacter pylori by triple therapy.

BACKGROUNDS AND AIMS: Polymorphisms of proinflammatory cytokines, such as interleukin (IL) 1beta and tumor necrosis factor (TNF) alpha, are associated with individual differences in gastric mucosal inflammation and acid inhibition in response to Helicobacter pylori infection. We investigated whether inflammation-related cytokine polymorphisms would influence the eradication rates of H pylori by a triple-therapy regimen. METHODS: Three hundred sixty patients infected with clarithromycin-sensitive strains of H pylori were genotyped for IL1B -511, IL1RN, TNFA -857/-863/-1,031, IL10 -1,082/-819/-592, and CYP2C19 and underwent triple therapy for 1 week with a proton pump inhibitor (20 mg omeprazole, 30 mg lansoprazole, or 10 mg rabeprazole) twice daily, 400 mg clarithromycin twice daily, and 750 mg amoxicillin (INN, amoxicilline) twice daily. The influences of the previously mentioned polymorphisms on the eradication rates were analyzed. RESULTS: The intention-to-treat-based total eradication rate was 83.6% (301/360). The logistic regression analysis revealed that polymorphisms of CYP2C19 and IL1B -511 were independently associated with the eradication rates, but other cytokine polymorphisms were not associated with these rates. The eradication rates in patients with IL1B -511 C/C, C/T, and T/T genotypes were 72.2% (70/97), 87.7% (164/187), and 88.2% (67/76), respectively (P = .0017). When patients were stratified by CYP2C19 genotype status, IL1B -511 genotype-dependent differences in eradication rates were observed in homozygous extensive metabolizers (EMs) but not in heterozygous EMs and poor metabolizers of CYP2C19. The eradication rate in homozygous EM patients with the IL1B -511 C/C genotype was quite low (51.1% [22/43]). CONCLUSIONS: IL1B -511 polymorphism, but not IL1RN, TNFA, or IL10 polymorphism, is one of the determinants of triple therapy for clarithromycin-sensitive strains of H pylori in CYP2C19 homozygous EMs.

Anti-Bacterial Agents↗
PubMed2004

Efficacy of clarithromycin against Streptococcus pneumoniae expressing mef(A)-mediated resistance.

As a result of macrolide resistance rates of 25% for pneumococci in the US, the clinical use of this class as empirical therapy has been questioned. However, macrolides continue to be used with clinical success. Using an immunocompromised murine pneumonia model, this study evaluated in vivo efficacy of human simulated exposures of clarithromycin for 62 isolates of Streptococcus pneumoniae considered resistant by current methods of breakpoint determinations. Changes in bacterial density were compared between treated animals and untreated controls. Inhibition of bacterial growth was consistently observed for the majority of isolates tested with mean (S.D.) reductions in logCFU per lung of -0.88 (0.69), -1.02 (0.87), -0.47 (0.79), -0.84 (0.66), -0.25 (0.26), -0.80 (0.72) and -0.58 (0.47) for MICs of 1, 2, 4, 8, 16, 32 and 64 mg/l, respectively. A beneficial treatment effect was clearly noted for isolates with clarithromycin MICs <==8 mg/l. However, the sample size of isolates tested beyond the MIC of 8 mg/l was diminished due to mortality in both treated and untreated animals. Consistent suppression of bacterial growth observed in this neutropenic model provides support for the in vivo efficacy of clarithromycin with low-level macrolide-resistant S. pneumoniae.

Animals↗