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PubMed2005

Effect of clarithromycin on the enantioselective disposition of lansoprazole in relation to CYP2C19 genotypes.

The aim of this study was to examine the effect of clarithromycin, a CYP3A4 inhibitor, on the enantioselective disposition of lansoprazole among three different CYP2C19 genotype groups in healthy Japanese subjects. These subjects included 6 each of homozygous extensive metabolizers (homEMs), heterozygous extensive metabolizers (hetEMs), and poor metabolizers (PMs). In the EMs of CYP2C19, clarithromycin markedly increased Cmax and the AUC0-infinity of (S)-lansoprazole and (S)-hydroxylansoprazole compared with those of the corresponding (R)-enantiomers. Clarithromycin significantly increased Cmax and the AUC0-infinity of (S)-lansoprazole in the homEMs by 110% and 115%, respectively, and in the hetEMs by 105% and 103%, respectively, compared with placebo. Furthermore, clarithromycin slightly prolonged the elimination half-life of (R)-lansoprazole in the homEMs and hetEMs but did not alter that of (S)-lansoprazole. In the of PMs CYP2C19, clarithromycin significantly increased Cmax and the AUC0-infinity and significantly prolonged the elimination half-lives of (R)- and (S)-lansoprazole by 51% and 49%, respectively. The present study suggests that there are significant drug interactions between (R)- or (S)-lansoprazole and clarithromycin in EMs by inhibiting the CYP3A4-catalyzed sulfoxidation primarily during the first pass, whereas in PMs, the overall metabolism of lansoprazole is inhibited.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed1991

Bactericidal activity of clarithromycin and its 14-hydroxy metabolite against Haemophilus influenzae and streptococcal pathogens.

The serum bactericidal activity of clarithromycin in six normal human volunteers was determined after oral doses of 500 mg. The mean plasma levels of clarithromycin plus 14-hydroxy clarithromycin were 2.11 micrograms/mL after the second dose and 4.36 micrograms/mL after the sixth dose. The mean serum bactericidal titer against Haemophilus influenzae after the second dose was 1:8 and after the sixth dose 1:16 when unheated serum was used. Similar values were obtained when serum to which clarithromycin and 14-hydroxy clarithromycin was added was tested. Mean serum bactericidal titers against H. influenzae determined in Haemophilus test broth or heated serum were 1:2 and 1:4, respectively. Against Streptococcus pneumoniae and Streptococcus pyogenes, there was greater than 1:16 serum bactericidal levels at 12 hours after the sixth dose of clarithromycin.

Administration, Oral↗

PubMed2006

Effects of clarithromycin and verapamil on rabeprazole pharmacokinetics between CYP2C19 genotypes.

OBJECTIVE: Rabeprazole as a proton pump inhibitor (PPI) is mainly reduced to rabeprazole thioether via a nonenzymatic pathway, with minor CYP2C19 and CYP3A4 involvement. The aim of this study was to compare possible effects of clarithromycin and verapamil as inhibitors of CYP3A4 on the pharmacokinetics of rabeprazole among CYP2C19 genotypes. METHODS: A three-way randomized, double-blind, placebo-controlled crossover study was performed. Nineteen volunteers, of whom six were homozygous extensive metabolizers (EMs), eight were heterozygous EMs, and five were poor metabolizers (PMs) for CYP2C19, received three 6-day courses of either daily 800 mg clarithromycin, 240 mg verapamil, or placebo in a randomized fashion, with a single oral dose of 20 mg rabeprazole on day 6 in all cases. Plasma concentrations of rabeprazole and rabeprazole thioether were monitored up to 24 h after the dosing. RESULTS: In the control phase, the AUC(0-infinity) values for rabeprazole and rabeprazole thioether were 1,005+/-366 and 412+/-149 ng.h/ml in homozygous EMs, 1,108+/-340 and 491+/-245 ng.h/ml in heterozygous EMs, and 2,697+/-364 and 2,116+/-373 ng.h/ml in PMs, respectively. There were significant differences (p<0.001) in the AUC(0-infinity) of rabeprazole and rabeprazole thioether among three different CYP2C19 genotypes. In the clarithromycin and verapamil phases, no significant differences were found in the pharmacokinetic parameters of rabeprazole compared with those in the control phase irrespective of CYP2C19 genotypes, whereas the AUC(0-infinity) of rabeprazole thioether was significantly increased 2.8-fold and 2.3-fold in homozygous EMs (p<0.01), 2.0-fold and 2.0-fold in heterozygous EMs (p<0.05), and 1.6-fold and 1.9-fold in PMs (p<0.05), respectively. In each genotype group for CYP2C19, there were no statistical differences in the percent increase in those pharmacokinetic parameters between the clarithromycin and verapamil pretreatment phases. CONCLUSION: The pharmacokinetic parameters of rabeprazole were not altered by clarithromycin or verapamil irrespective of the CYP2C19 genotypes. However, this result shows that both clarithromycin and verapamil significantly influence the disposition of rabeprazole by inhibiting the oxidation of the thioether, since the AUC(0-infinity) of rabeprazole thioether that has no effect on acid secretion increased. Therefore, the pharmacokinetic interactions between rabeprazole and CYP3A4 or P-glycoprotein inhibitors have limited clinical significance.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed1997

Clarithromycin is a potent inhibitor of tumor-induced angiogenesis.

We investigated the inhibitory effect of clarithromycin, a 14-membered ring macrolide antibiotic, on tumor-induced angiogenesis in vivo using a mouse dorsal air sac model. The inhibitory effect of clarithromycin was dose-dependent, and 100 mg/kg of clarithromycin administered intraperitoneally twice a day reduced the area of dense capillary network to about 30% that of the control. However, in concentrations up to 50 microM clarithromycin had no effect on lung cancer cells and human vascular endothelial cell growth, endothelial cell migration, or lung cancer cell production of the angiogenesis-inducing factors interleukin-8 and vascular endothelial growth factor. Clarithromycin in concentrations greater than 10 microM inhibited endothelial cell tube formation on Matrigel in a dose-dependent manner. These data suggest clarithromycin is a potent inhibitor of tumor-induced angiogenesis that exerts its effect by inhibiting endothelial cell tube formation, and may be a possible candidate for therapeutic application.

Animals↗

PubMed1998

Randomized, multicentre study of the efficacy and tolerance of azithromycin versus clarithromycin in the treatment of adults with mild to moderate community-acquired pneumonia. Azithromycin Study Group.

Adults with mild to moderate community-acquired pneumonia were treated with azithromycin (500 mg once daily for 3 days) or clarithromycin (250 mg twice daily for 10 days) and clinically assessed between days 3 and 7 and days 12 and 16. Patients classified as improved at the day 12-16 visit were also evaluated between days 19 and 23. Two hundred three patients were treated (101 with azithromycin, 102 with clarithromycin). A satisfactory clinical response was recorded at the end of therapy in 83 of 88 (94%) evaluable azithromycin-treated and 84 of 88 (95%) evaluable clarithromycin-treated patients (P=0.518). At day 19-23, only one patient in each treatment group had relapsed. Thirty-one of 32 (97%) pathogens isolated from patients in the azithromycin group were eradicated, compared with 32 of 35 (91%) isolated from clarithromycin patients. In all patients with atypical pneumonia, the clinical response was satisfactory at follow-up. Incidences of treatment-related adverse events were similar for the two groups (P=0.815). Two (2%) clarithromycin patients discontinued therapy due to severe treatment-related adverse events; none in the azithromycin group did. This study shows that a 3-day, once-daily course of azithromycin is as clinically effective and well tolerated as a 10-day, twice-daily course of clarithromycin in the treatment of mild to moderate community-acquired pneumonia.

Adolescent↗

PubMed1992

Clarithromycin, a unique macrolide. A pharmacokinetic, microbiological, and clinical overview.

The in vitro and in vivo spectrum of antibacterial activity of clarithromycin is summarized and related to its human pharmacokinetics. In vitro studies by several investigators have documented clarithromycin's activity against bacterial agents of respiratory tract infections, skin and soft tissue infections, and sexually transmitted diseases. Clinical cure rates of 52%-83% (pneumonia), 79%-96% (bronchitis), 82%-96% (pharyngitis), 58% (sinusitis), and 78% (skin/skin-structure infections) have been reported in patients receiving clarithromycin in comparative trials. Respective bacteriologic eradication rates in clarithromycin recipients have been reported as 57%-89%, 79%-96%, 88%-100%, 89%, and 90%. In vitro and in vivo studies suggest that clarithromycin, when combined with its major human metabolite, 14-hydroxyclarithromycin, is also effective against Haemophilus influenzae. A New Drug Application claiming efficacy in the treatment of lower respiratory tract infection, sinusitis, pharyngitis, and skin and skin-structure infections caused by susceptible pathogens has been filed with the Food and Drug Administration (FDA). This review summarizes relevant pharmacokinetic, microbiological, and clinical data for clarithromycin.

Clarithromycin↗

PubMed1994

Chloroquine does not enhance the activity of clarithromycin against multiplication of Mycobacterium avium within human macrophages.

SETTING: Chloroquine, an alkalinizing lysosomotropic agent, enhances the intracellular activity of antibiotics against Mycobacterium tuberculosis or Coxiella burnetii. OBJECTIVE: To determine if chloroquine modifies the activity of clarithromycin, less effective at acidic pH, against intracellular Mycobacterium avium. DESIGN: The activity of clarithromycin (4 micrograms/ml) against the MO-1 strain of M. avium was evaluated within human macrophages in presence of chloroquine (5 micrograms/ml). The minimal inhibitory concentration of clarithromycin for the strain was 2 micrograms/ml. RESULTS: While clarithromycin alone did decrease the intracellular infection at day 7 of culture (P < 0.01), chloroquine alone did not impede the intracellular growth of M. avium, and did not enhance the activity of clarithromycin. CONCLUSION: Chloroquine should not improve clarithromycin treatment against M. avium infection.

Cells, Cultured↗

PubMed2004

Corneal pharmacokinetics of topically applied azithromycin and clarithromycin.

PURPOSE: To determine corneal levels of topically administered azithromycin and clarithromycin in a rabbit model. DESIGN: Experimental animal study. METHODS: Corneas of New Zealand albino rabbits were treated with topical azithromycin (2 mg/ml or 4 mg/ml) or clarithromycin (10 mg/ml). Topical azithromycin was prepared from an intravenous solution and topical clarithromycin from a suspension for oral use. All rabbits received one drop every 2 hours on the right eye. Groups of rabbits were treated for the following intervals: 6, 12, 24, and 48 hours (four rabbits for each combination of time point, drug, and dose). Corneal tissue was removed 1 hour after the last application. To investigate stability of tissue azithromycin levels, an additional group of four rabbits was treated for 24 hours, but corneal tissue was not removed until 24 hours later. Samples were homogenized, and drug concentrations were measured using high-pressure liquid chromatography (HPLC) analysis and bioactivity assay. RESULTS: Corneal concentrations of azithromycin increased with drug dosage and duration of application. Rabbits treated with azithromycin tolerated the drug well without signs of irritation. Clarithromycin was undetectable in corneal tissue by HPLC and bioactivity assay for all rabbits. Some rabbits treated with clarithromycin had signs of ocular surface irritation. CONCLUSION: Measurable concentrations of azithromycin are achieved in corneal tissue after topical application in a rabbit model, and the drug is well tolerated. Azithromycin may be a useful antibiotic for the topical treatment of human corneal infections, but clarithromycin, in currently available formulations, may not be effective because of poor tissue penetration.

Administration, Topical↗

PubMed2005

Rifabutin based triple therapy for eradication of H. pylori primary and secondary resistant to tinidazole and clarithromycin.

BACKGROUND: Rifabutin has been empirically used in Helicobacter pylori infections resistant to triple therapy. There are no data on primary and secondary resistance to rifabutin and its use in specific cases. AIM: To analyse the susceptibility and resistance to rifabutin in H. pylori-positive patients with or without previous H. pylori therapy and to test the efficacy of rifabutin in H. pylori resistant to clarithromycin and tinidazole. METHODS: Four hundred and twenty H. pylori-positive patients without previous exposure to triple therapy and 104 patients who had already received one course of triple therapy underwent upper endoscopy for dyspeptic symptoms and H. pylori susceptibility test. Amoxicillin, clarithromycin, tinidazole and rifabutin were evaluated for resistance and susceptibility. Forty patients with primary resistance to both clarithromycin and tinidazole and with susceptibility to amoxicillin and rifabutin, and 65 patients with secondary resistance and susceptibility to the same antibiotics were identified. All these patients received a 10-day triple therapy with pantoprazole amoxicillin and rifabutin. Treatment success was evaluated by the 13C-Urea Breath test. RESULTS: In naive patients 23% of strains were resistant to clarythromycin, 35% to tinidazole, 9% to both antibiotics, and none was resistant to rifabutin In patients already treated the percentages of resistant strains were 76, 64.4, 62.5 and 1%, respectively. With rifabutin based triple therapy eradication rates were (Per Protocol and Intention-to-Treat analysis) 100 and 87.5% in primary resistance to clarithromycin and tinidazole and 82.2 and 78.5% in secondary resistance. CONCLUSION: H. pylori primary and secondary resistances to clarithromycin and tinidazole are high in our geographic area, while resistance to rifabutin is rare. Rifabutin-based triple therapy, can be successfully used in primary and secondary resistance to clarithromycin and tinidazole according to the in vitro susceptibility test.

Adult↗

PubMed1998

Endothelial cell compatibility of clarithromycin for intravenous use.

OBJECTIVES: Tolerance of intravenously applied clarithromycin has been tested on marginal ear veins of rabbits. Use of human umbilical venous endothelial cells (HUVEC) for testing antibiotic solutions for intravenous compatibility provides a valuable alternate model. DESIGN AND METHODS: In order to evaluate the effect of clarithromycin on intracellular purines, reflecting cell viability, energy production, signal transduction and DNA/RNA synthesis, intracellular adenosine 5' triphosphate (ATP), adenosine 5' diphosphate (ADP), guanosine 5' triphosphate (GTP), and guanosine 5' diphosphate (GDP) levels were measured by means of high performance liquid chromatography (HPLC). RESULTS: Incubation of cells with 2 mg/mL clarithromycin resulted in a rapid decrease of the intracellular ATP from 12.6 +/- 1.1 to 8.87 +/- 0.82 nmol/million cells or 1.5 +/- 0.6 nmol/million cells, after 20 or 60 min, respectively. In addition, ADP was extensively depleted. Purine nucleotide profiles were markedly different following exposure to 1 mg/mL clarithromycin. There was no significant decline of intracellular high energy phosphate levels after 20 min. CONCLUSION: These results show that clarithromycin has a better endothelial compatibility if diluted to a final concentration of 1 mg/mL. These data are in line with our clinical observations that the occurrence of phlebitis could be minimized by diluting the manufacturers' preparation of clarithromycin to 1 mg/mL.

Adenine↗

PubMed1998

Effect of clarithromycin on renal excretion of digoxin: interaction with P-glycoprotein.

We present a digoxin-clarithromycin interaction in two patients in whom digoxin concentrations were unexpectedly increased. The ratio of renal digoxin clearance to creatinine clearance in one patient was lower during the concomitant administration of clarithromycin (0.64 and 0.73) than that after cessation of clarithromycin administration (1.30 +/- 0.20; mean +/- SD). Because P-glycoprotein could play an important role in the renal secretion of digoxin, we hypothesized that clarithromycin decreases renal digoxin excretion by inhibiting P-glycoprotein-mediated transport. Digoxin transport was evaluated with use of a kidney epithelial cell line, which expresses the human P-glycoprotein on the apical membrane by transfection with MDR1 complementary deoxyribonucleic acid. Clarithromycin inhibited the transcellular transport of digoxin from the basolateral to the apical side in a concentration-dependent manner and concomitantly increased the cellular accumulation of digoxin. These results suggest that clarithromycin may inhibit the P-glycoprotein-mediated tubular secretion of digoxin, and this interaction mechanism may contribute to an increase in the serum digoxin concentration.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1994

Comparative study of the safety and efficacy of clarithromycin and amoxicillin-clavulanate in the treatment of acute otitis media in children.

The safety and efficacy of clarithromycin was compared with those of amoxicillin-potassium calvulanate for the treatment of acute otitis media in children. In a multicenter, randomized, investigator-blinded trial, 180 patients (6 months to 12 years of age) with acute otitis media were allocated to receive either clarithromycin, 15 mg/kg in two divided doses (n = 90), or amoxicillin-clavulanate, 40 mg/kg in three divided doses (n = 90), for 10 days. Middle ear samples were obtained by tympanocentesis from 175 of 180 patients. Pathogens were isolated from 137 samples (76%). Eighty-six patients in each treatment group were considered for efficacy analysis. Clinical cure or improvement was achieved within 4 days after treatment in 80 (93%) of 86 patients receiving clarithromycin and in 82 (95%) of 86 patients receiving amoxicillin-clavulanate. Recurrence of infection was observed between 5 and 35 days after treatment in 9 (11%) of 80 patients in the clarithromycin group and in 8 (10%) of 82 patients in the amoxicillin-clavulanate group. Middle ear effusion was found with similar frequency at the end of therapy and at follow-up visits in both treatment groups. Mild gastrointestinal signs and symptoms, the most common side effects, were noted in 20% and 52% of patients in the clarithromycin group and the amoxicillin-clavulanate group, respectively (p < 0.001). We conclude that clarithromycin is a safe and effective antimicrobial agent for the treatment of acute otitis media in children.

Acute Disease↗

PubMed1996

Efficacy of short-term treatment of pertussis with clarithromycin and azithromycin.

The recommended treatment for pertussis is erythromycin, 40 to 50 mg/kg per day for 2 weeks. The newly developed macrolides, clarithromycin and azithromycin, have been demonstrated to be superior to erythromycin because of improved absorption and a longer half-life. As a result, we conducted two separate comparison studies to evaluate the efficacies of clarithromycin, 10 mg/kg per day, twice a day for 7 days, and azithromycin, 10 mg/kg per day, once a day for 5 days, compared with the standard erythromycin regimen. A total of 17 patients, including 10 infants 1 year of age or less, for whom pertussis had been confirmed by culture, were allocated to receive either clarithromycin or azithromycin treatment, and each patient was matched (age, sex, and immunization status) with historical control subjects who had been treated with erythromycin. Eradication rates examined at 1 week after treatment were as follows: 9 of 9 with clarithromycin versus 16 of 18 with erythromycin (psi M-H = 1.13), and 8 of 8 with azithromycin versus 13 of 16 with erythromycin (psi M-H = 1.23). No bacterial relapse after treatment was detected in either group. All isolated strains of Bordetella pertussis were susceptible to clarithromycin, azithromycin, and erythromycin, and no change in drug susceptibility has been confirmed for the past 20 years in Japan. Because of the very low incidence of pertussis resulting from widespread use of acellular pertussis vaccination, this study did not enroll a large number of patients; however we conclude that short-term treatment with clarithromycin or azithromycin is expected to be equal or superior to the standard long-term erythromycin regimen for pertussis.

Adolescent↗

PubMed1999

Inhibition of methylprednisolone elimination in the presence of clarithromycin therapy.

BACKGROUND: Macrolide antibiotics have long been used as steroid-sparing agents in patients with severe steroid-dependent asthma. Their efficacy and their propensity to potentiate glucocorticoid adverse effects have been attributed in part to their ability to delay glucocorticoid clearance. OBJECTIVE: We sought to determine whether clarithromycin, a newer macrolide antibiotic, can alter the pharmacokinetic profile of oral glucocorticoids and thereby increase the risk of steroid-induced adverse effects. METHODS: An open-label study in a paired design (before and after treatment) was conducted in a hospital-based outpatient clinic. Participants were 6 adult patients (mean age, 30 years) with mild-to-moderate asthma. Prednisone (40 mg/1.73 m2) and methylprednisolone (40 mg/1.73 m2) were given as single randomized doses on consecutive study days before and on days 8 and 9 of a clarithromycin (500 mg twice daily) course. Twelve-hour pharmacokinetic profiles with measurement of plasma methylprednisolone and prednisolone levels were taken before and after clarithromycin therapy. RESULTS: Clarithromycin therapy resulted in a 65% reduction of methylprednisolone clearance and significantly higher mean plasma methylprednisolone concentrations compared with preclarithromycin concentrations but had no significant effect on prednisolone clearance or mean prednisolone plasma concentrations. CONCLUSIONS: Clinicians must be aware of potential drug interactions that could place patients at increased risk for steroid-induced adverse effects. Such an effect has been demonstrated between clarithromycin and methylprednisolone, two drugs that may be administered concomitantly in asthma. To avoid potential steroid-enhancing effects, prednisone should be substituted for methylprednisolone during prolonged courses of clarithromycin therapy.

Adult↗

PubMed2000

Phase III, randomized, double-blind study of clarithromycin extended-release and immediate-release formulations in the treatment of adult patients with acute maxillary sinusitis.

BACKGROUND: Clarithromycin has an established bacteriologic efficacy and safety profile in the treatment of respiratory tract infections. OBJECTIVE: This study compares the efficacy and tolerability of extended-release and immediate-release formulations of clarithromycin in patients with acute maxillary sinusitis. METHODS: Fourteen days' treatment with once-daily clarithromycin was compared with the immediate-release, twice-daily formulation in a phase III, randomized, double-blind, parallel-group, multicenter study. Patients aged > or =12 years with signs, symptoms, and a radiologically confirmed diagnosis of acute maxillary sinusitis were eligible. Patients were assessed before treatment, within 48 hours after treatment, on study days 16 to 18, and at the test-of-cure visit on study days 24 to 31. Patients who received > or =1 dose of study drug were included in the safety analysis. RESULTS: Of 283 patients treated, 245 were included in the efficacy analysis (122 in the extended-release group, 123 in the immediate-release group). Treatment groups were well matched with respect to demographic characteristics and medical condition and history. At the test-of-cure visit, 85% of patients in the clarithromycin extended-release group and 79% in the immediate-release group were deemed clinical cures; 89% and 91% in the extended-release and immediate-release groups, respectively, demonstrated radiographic success. Overall incidences of study drug-related adverse events were similar in the 2 treatment groups (32% in the extended-release group and 28% in the immediate-release group); however, significantly fewer patients receiving extended-release clarithromycin (2/142 11%]), compared with those receiving the immediate-release formulation (10/141 [7%]: P = 0.02) discontinued therapy because of drug-related gastrointestinal symptoms or abnormal taste. No clinically meaningful changes in laboratory values or vital signs were observed during the study. CONCLUSION: Although the efficacy of the 2 formulations was comparable, once-daily clarithromycin extended-release was better tolerated than the twice-daily immediate-release formulation by patients with acute maxillary sinusitis.

Acute Disease↗

PubMed2002

The pharmacokinetics of sumatriptan when administered with clarithromycin in healthy volunteers.

BACKGROUND: Macrolide antibiotics such as clarithromycin are potent inhibitors of the cytochrome P450 (CYP)3A4 isozyme and have the potential to attenuate the metabolism and increase blood concentrations of drugs metabolized by this pathway. In vitro studies have suggested that sumatriptan is metabolized primarily by the monoamine oxidase-A isozyme and not by CYP3A4. OBJECTIVE: This study sought to determine the effect of coadministration of clarithromycin dosed to steady state on the pharmacokinetics of a single dose of sumatriptan. A secondary objective was to assess the safety and tolerability of combining these agents. METHODS: This was an open-label, randomized, 2-way crossover study in healthy volunteers. During treatment period 1, subjects received either a single oral dose of sumatriptan 50 mg (sumatriptan alone) or clarithromycin 500 mg orally every 12 hours on days 1 to 3 and a single oral dose of sumatriptan 50 mg plus a single oral dose of clarithromycin 500 mg on the morning of day 4 (combination treatment). During treatment period 2, they received the alternative regimen. Equivalence between sumatriptan alone and combination treatment was concluded if the 90% CI for the ratio of reference to test means of loge-transformed data for area under the plasma concentration-time curve extrapolated to infinity (AUC(infinity)) and maximum plasma concentration (Cmax) fell within the interval from 0.8 to 1.25. RESULTS: In the 24 evaluable subjects (12 men, 12 women) included in the pharmacokinetic analysis, mean sumatriptan AUC(infinity) and Cmax values after administration of combination treatment were 9% and 14% higher, respectively, than the corresponding values after administration of sumatriptan alone. The 90% CI for the ratio of reference to test means for AUC(infinity) was 1.03 to 1.15. The 90% CI for the ratio of reference to test means for Cmax was 1.03 to 1.26, above the traditional bioequivalence criterion. All other pharmacokinetic parameters tested, including nonparametric analysis of the time to Cmax, met the criterion for equivalence between treatments. Both treatments were well tolerated in the 27 subjects (13 men, 14 women) included in the safety analysis. CONCLUSIONS: The extent of absorption of sumatriptan was similar after oral administration alone and in combination with clarithromycin dosed to steady state. These data are consistent with previous reports that sumatriptan is unaffected by coadministration with the potent CYP3A4 inhibitor clarithromycin, supporting concomitant administration of these agents without the need for dose adjustment of sumatriptan in the acute treatment of migraine.

Adolescent↗

PubMed1999

Treating acute bacterial exacerbations of chronic bronchitis in patients unresponsive to previous therapy: sparfloxacin versus clarithromycin.

The optimal antibiotic therapy for patients with acute bacterial exacerbations of chronic bronchitis (ABECB) who have failed to respond to previous oral antimicrobial therapy is not known; however, newer macrolide and fluoroquinolone antibiotics may be appropriate. This multicenter, randomized, double-masked, double-dummy study was undertaken to compare the efficacy and tolerability of sparfloxacin with those of clarithromycin in the treatment of ABECB. In 43 centers in the United States, 298 patients (52% male; age range, 19 to 92 years) were randomly allocated to receive a 400-mg loading dose of sparfloxacin, followed by 200 mg once daily, or clarithromycin 500 mg twice daily, for a total of 10 days. Signs and symptoms of ABECB were assessed at each of 4 visits, including a follow-up visit approximately 1 month after the completion of therapy. Efficacy was determined on the basis of the clinical and bacteriologic response rates in the clinically assessable population. Tolerability was assessed on the basis of patient reports, clinical evaluations, and laboratory tests. Of the 266 clinically assessable patients, 109 (85.2%) of 128 patients receiving sparfloxacin and 115 (83.3%) of 138 patients receiving clarithromycin had a clinically successful outcome (cure or improvement). The bacteriologic success rate (eradication of pathogen) was 88.9% (64 of 72 isolates) in the sparfloxacin group and 84.7% (83 of 98 isolates) in the clarithromycin group. Adverse events possibly or probably related to study drug included photosensitivity in 12 (8.3%) and rash in 6 (4.1%) of 145 patients in the sparfloxacin group, and diarrhea in 10 (6.5%), taste perversion in 9 (5.9%), and nausea in 8 (5.2%) of 153 patients in the clarithromycin group. Thus sparfloxacin was as well tolerated and as effective as clarithromycin in the treatment of patients with ABECB unresponsive to previous oral antimicrobial therapy. The overall rate of adverse events was comparable for the 2 study drugs, but the types of events differed.

Acute Disease↗

PubMed1999

Metronidazole and clarithromycin resistance amongst Helicobacter pylori isolates from a large metropolitan hospital in the United States.

BACKGROUND: Metronidazole and clarithromycin-based therapies are among the most efficacious treatment regimens for H. pylori infection. Resistance to metronidazole or clarithromycin is associated with impaired therapy with these agents. We conducted a retrospective review of susceptibility data to determine the frequency of primary metronidazole and clarithromycin resistance among H. pylori isolates from a single metropolitan hospital in the United States. The database comprised 933 patients who presented at the Digestive Diseases Clinic at the Veterans Affairs Medical Center in Houston between September 1988 and January 1997 with complaints of dyspepsia, abdominal pain and peptic ulcer disease. One hundred and seventy-nine of these patients had both pharmaceutical records available for evaluation and culture and antimicrobial susceptibility data for analysis. The MICs were determined by both E-test and broth microdilution tests. The frequency of primary metronidazole resistance was 37.4% (67/179). The level of primary clarithromycin resistance was 6.1%. Dual metronidazole and clarithromycin resistance was present in approx. 3%. The high level of primary metronidazole and clarithromycin resistance in H. pylori isolates from this metropolitan hospital is such that antimicrobial susceptibility data should be available so that informed choice can be made for specific eradication therapies, especially in patients who fail treatment.

Anti-Bacterial Agents↗