ABSTRACT
BACKGROUND: Data from large, multicenter, US studies determining the efficacy of triple therapy for the eradication of Helicobacter pylori are lacking, especially for a treatment duration of less than 14 days. METHODS: Patients with H pylori infection and active duodenal ulcer disease or a history of duodenal ulcer disease within the past year were randomized to receive 30 mg of lansoprazole, 1 g of amoxicillin, and 500 mg of clarithromycin twice daily for 10 or 14 days. The primary efficacy end point was the eradication of H pylori as confirmed by negative histological and culture results at 4 to 6 weeks after the completion of treatment. RESULTS: Of 284 patients enrolled in the study from 46 US sites, 236 met the entry criteria. At 4 to 6 weeks after the end of therapy, H pylori was eradicated in 85% (96/ 113) of the patients receiving 14-day triple therapy and in 84% (103/123) of those receiving 10-day triple therapy by per-protocol analysis (95% confidence interval for treatment group differences, -10.5 to 8.1; P>.05). There was also no significant difference between the 14- and 10-day treatment groups when analyzed by an intent-to-treat analysis of H pylori eradication. A similar proportion of patients in each treatment group reported an adverse event related to therapy (34% [46/136] vs 38% [56/148], respectively). CONCLUSIONS: In patients with an active or a recent history of duodenal ulcer, lansoprazole-based triple therapy for 10 or 14 days is highly effective in the eradication of H pylori. The duration of therapy may be reduced from 14 to 10 days without a significant effect on regimen efficacy.
Subject(s)
Anti-Bacterial Agents/administration & dosage , Anti-Ulcer Agents/administration & dosage , Duodenal Ulcer/microbiology , Helicobacter Infections/drug therapy , Helicobacter pylori , Omeprazole/analogs & derivatives , 2-Pyridinylmethylsulfinylbenzimidazoles , Amoxicillin/administration & dosage , Amoxicillin/therapeutic use , Anti-Bacterial Agents/therapeutic use , Anti-Ulcer Agents/therapeutic use , Clarithromycin/administration & dosage , Clarithromycin/therapeutic use , Double-Blind Method , Drug Administration Schedule , Drug Therapy, Combination , Duodenal Ulcer/drug therapy , Female , Humans , Lansoprazole , Male , Middle Aged , Omeprazole/administration & dosage , Omeprazole/therapeutic use , Proton Pump Inhibitors , Time FactorsABSTRACT
OBJECTIVE: To compare the efficacy of two- and three-drug regimens for treating Mycobacterium avium complex (MAC) bacteremia in patients with AIDS. DESIGN: Randomized open-label clinical trial. SETTING: Outpatient HIV specialty centers' clinics. PATIENTS: A total of 106 adults with AIDS and MAC bacteremia. INTERVENTIONS: Patients were treated with clarithromycin 500 mg twice daily and ethambutol 800-1,000 mg daily and were randomized to receive clofazimine 100 mg daily or no clofazimine. MAIN OUTCOME MEASURES: Quantitative blood MAC cultures, symptoms, adverse reactions and survival. RESULTS: Patients randomly assigned to three drugs had significantly higher baseline colony counts of MAC in blood than patients receiving two drugs. The proportion of patients becoming culture-negative was 65% in the two-drug group and 54% in the three-drug group. The median time to negative culture was 58 days for patients in the two-drug and 63 days for the three-drug group. At the last visit during treatment, the mean reduction in colony forming units/ml of MAC in blood was 1.8 log10 for the two-drug group and 2.3 log10 for the three-drug group. Improvement in fever and night sweats was reported by 87 and 89% of the two-drug patients and 84 and 86% of the three-drug patients. During the study, 38% of two-drug patients and 61% of three-drug patients died (P = 0.032), and time to death was shorter in patients treated with three drugs (P = 0.012). In a multivariate analysis, both assignment to clofazimine and high baseline colony counts of MAC bacteremia were significantly associated with death (P < 0.05). CONCLUSION: The addition of clofazimine to a regimen of clarithromycin and ethambutol for MAC bacteremia in AIDS patients does not contribute to clinical response and is associated with higher mortality.
Subject(s)
AIDS-Related Opportunistic Infections/drug therapy , Anti-Bacterial Agents/therapeutic use , Antitubercular Agents/therapeutic use , Clarithromycin/therapeutic use , Clofazimine/therapeutic use , Ethambutol/therapeutic use , Mycobacterium avium-intracellulare Infection/drug therapy , Adult , Anti-Bacterial Agents/administration & dosage , Antitubercular Agents/administration & dosage , Clarithromycin/administration & dosage , Clofazimine/administration & dosage , Drug Resistance, Microbial , Drug Therapy, Combination , Ethambutol/administration & dosage , Female , Humans , Male , Mycobacterium avium-intracellulare Infection/complicationsABSTRACT
The efficacy and safety of orally administered clarithromycin and erythromycin in the treatment of community-acquired pneumonia were assessed in a multicenter, double-blind, randomized study. Two hundred sixty-eight patients were randomized to receive either clarithromycin, 250 mg twice a day, or erythromycin stearate, 500 mg 4 times a day, for 7 to 14 days. Efficacy was evaluable in 173 patients (92 for clarithromycin, 81 for erythromycin). No statistically significant difference in clinical success rate (cure or improvement) was observed between the two groups (clarithromycin, 97 percent; erythromycin, 96 percent). Both groups had identical radiologic response (97 percent with resolution or improvement). Similarly, no statistically significant difference in bacteriologic response toward the target pathogens was observed among evaluable patients (clarithromycin, 23/26; erythromycin, 17/17; p value = 0.287). Clinical response toward Mycoplasma and Chlamydia pneumonia was comparable between the two groups (clarithromycin, 15/16; erythromycin, 10/11). However, patients receiving erythromycin had a twofold higher incidence of adverse events, mostly related to the gastrointestinal system, and were five times more likely to withdraw from therapy because of drug-related adverse events. These results show that clarithromycin is as effective as erythromycin in the outpatient treatment of community-acquired pneumonia. Furthermore, the lower incidence of adverse events associated with clarithromycin indicates that it is more acceptable to patients and, therefore, can enhance compliance.
Subject(s)
Clarithromycin/therapeutic use , Erythromycin/therapeutic use , Pneumonia/drug therapy , Adolescent , Adult , Aged , Aged, 80 and over , Analysis of Variance , Canada , Child , Clarithromycin/adverse effects , Double-Blind Method , Erythromycin/adverse effects , Female , Humans , Male , Pneumonia/diagnosis , Sweden , TabletsABSTRACT
Results of preclinical studies conducted to characterize the safety of clarithromycin oral suspension in juvenile mice, rats and dogs as compared with that in adult animals indicate that there is no enhanced risk in younger animals. Adverse events in these preclinical studies mainly involved decreased body and increased liver and kidney weights. The safety profile of clarithromycin suspension also has been evaluated in Phase II (pharmacokinetic) and III (clinical) United States and international clinical trials conducted in pediatric patients. The most frequently reported adverse events occurring among the 1676 patients studied who received clarithromycin suspension in Phase III trials included diarrhea (7%), vomiting (6%), abdominal pain (2%), headache (2%) and nausea (1%). Adverse events were not serious and were usually rapidly reversible. Adverse event rates did not vary with sex or race. Overall adverse event rates were generally similar to those of comparator beta-lactam suspensions (i.e. amoxicillin, amoxicillin/clavulanate, penicillin VK, cefaclor, cefadroxil). With regard to specific gastrointestinal events, however, clarithromycin was better tolerated than amoxicillin/clavulanate whereas penicillin VK showed a lower incidence of gastrointestinal events. Overall clarithromycin oral suspension appears to be safe and well-tolerated, making it suitable for use in the pediatric population.
Subject(s)
Clarithromycin/administration & dosage , Clarithromycin/adverse effects , Animals , Cephalosporins/adverse effects , Child , Child, Preschool , Clarithromycin/toxicity , Clinical Trials as Topic , Drug Interactions , Female , Humans , Infant , Male , Penicillins/adverse effects , SuspensionsABSTRACT
BACKGROUND: Given the therapeutic potential of proton pump inhibitor-based triple therapy for successful cure of Helicobacter pylori infection, we evaluated the efficacy and safety of lansoprazole with clarithromycin and amoxicillin in an open-label, single-center study. MATERIALS AND METHODS: H. pylori-positive patients self-administered lansoprazole, 30 mg; clarithromycin, 500 mg; and amoxicillin, 1 gm bid for 14 days. Patients were assessed pretreatment, at which time the presence of H. pylori was documented by rapid urease test, culture, or histology, following study drug administration (week 2) for a brief evaluation only, and at least 4 weeks posttreatment (week 6), which included endoscopy with collection of biopsy specimens for culture and histology testing. RESULTS: Primary clarithromycin and metronidazole resistance were observed in 6% (2 of 30) and 43% (13 of 30) of study patients, respectively. One month after the end of therapy, H. pylori infection was cured in 23 of 25 patients (92%; 95% confidence interval, 74%-99%). The triple-therapy regimen was well-tolerated; 17% of patients (5 of 30) reported mild to moderate adverse effects during the treatment period. CONCLUSION: A 2-week, triple-drug combination of lansoprazole, clarithoromycin, and amoxicillin is highly effective for cure of H. pylori infection. Additionally, the triple-drug combination was well-tolerated by patients infected with H. pylori.
Subject(s)
Amoxicillin/therapeutic use , Clarithromycin/therapeutic use , Drug Therapy, Combination/therapeutic use , Enzyme Inhibitors/therapeutic use , Helicobacter Infections/drug therapy , Helicobacter pylori , Omeprazole/analogs & derivatives , Proton Pump Inhibitors , 2-Pyridinylmethylsulfinylbenzimidazoles , Adult , Aged , Amoxicillin/administration & dosage , Clarithromycin/administration & dosage , Drug Therapy, Combination/administration & dosage , Enzyme Inhibitors/administration & dosage , Female , Gastric Mucosa/microbiology , Helicobacter pylori/isolation & purification , Humans , Lansoprazole , Male , Middle Aged , Omeprazole/administration & dosage , Omeprazole/therapeutic use , Treatment OutcomeABSTRACT
BACKGROUND: Treatment with amoxicillin plus omeprazole results in disappointing cure rates of Helicobacter pylori infection. The minimal inhibitory concentration of lansoprazole for H. pylori in vitro is lower than that for omeprazole, prompting interest in treatment with amoxicillin plus lansoprazole. MATERIALS AND METHODS: H. pylori-infected patients with endoscopically documented duodenal ulcer either currently or within the past year were randomized to 14 days of (1) lansoprazole, 30 mg bid, plus amoxicillin, 1 gm tid; (2) lansoprazole, 30 mg tid, plus amoxicillin, 1 gm tid; (3) lansoprazole, 30 mg tid alone; or (4) amoxicillin, 1 gm tid alone. Endoscopy was done at enrollment and at 4 to 6 weeks after completion of treatment or for recurrent symptoms. H. pylori status was assessed by culture and histology. Ulcer prevalence was evaluated at follow-up endoscopy. RESULTS: Two hundred sixty-two patients met enrollment criteria and were treated. By per-protocol analysis, H. pylori infection was cured in 57% of those treated with lansoprazole twice daily plus amoxicillin and in 67% of those treated with lansoprazole three times daily plus amoxicillin, compared with 0% treated with lansoprazole alone or amoxicillin alone (p < .001 for dual therapy versus either monotherapy). Amoxicillin resistance was not observed. At follow-up endoscopy, ulcer prevalence was 17% in patients treated with lansoprazole twice daily plus amoxicillin, 23% in those treated with lansoprazole three times daily plus amoxicillin, 33% in those treated with lansoprazole alone, and 35% in those treated with amoxicillin alone (p = .024; lansoprazole twice daily plus amoxicillin versus amoxicillin alone). CONCLUSIONS: Treatment with amoxicillin plus lansoprazole, 30 mg tid, led to cure of H. pylori infection in 67% of patients with active or recently healed duodenal ulcer.
Subject(s)
Amoxicillin/therapeutic use , Anti-Ulcer Agents/therapeutic use , Duodenal Ulcer/drug therapy , Enzyme Inhibitors/therapeutic use , Gastritis/drug therapy , Helicobacter Infections/drug therapy , Helicobacter pylori , Omeprazole/analogs & derivatives , Penicillins/therapeutic use , 2-Pyridinylmethylsulfinylbenzimidazoles , Adult , Amoxicillin/administration & dosage , Amoxicillin/adverse effects , Anti-Ulcer Agents/administration & dosage , Clarithromycin/pharmacology , Diarrhea/chemically induced , Double-Blind Method , Drug Eruptions/etiology , Drug Resistance, Microbial , Drug Therapy, Combination , Duodenal Ulcer/epidemiology , Duodenal Ulcer/etiology , Duodenal Ulcer/microbiology , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/adverse effects , Female , Gastritis/complications , Gastritis/microbiology , Helicobacter Infections/complications , Helicobacter Infections/microbiology , Helicobacter pylori/drug effects , Helicobacter pylori/isolation & purification , Humans , Hypertension/chemically induced , Lansoprazole , Male , Metronidazole/pharmacology , Middle Aged , Omeprazole/administration & dosage , Omeprazole/adverse effects , Omeprazole/therapeutic use , Penicillins/administration & dosage , Penicillins/adverse effects , Prevalence , Proton Pump Inhibitors , Research Design , Treatment OutcomeABSTRACT
BACKGROUND: To refine our understanding of anti-Helicobacter pylori treatment regimens further, we evaluated the efficacy and safety of lansoprazole given in combination with clarithromycin and metronidazole for 7 days in an open-label, multicenter study. MATERIALS AND METHODS: H. pylori-positive patients self-administered lansoprazole, 30 mg; clarithromycin, 500 mg; and metronidazole, 500 mg bid for 7 days. Patients were assessed at pretreatment, at which time the presence of H. pylori was documented by rapid urease test or histology and culture, following study drug administration (week 1) for a brief evaluation only, and at least 4 weeks posttreatment (week 5), including endoscopy with collection of biopsy specimens for culture and histology testing. RESULTS: Of the 60 patients enrolled in the study, 59 had confirmed H. pylori infection, and 51 were included in an intent-to-treat analysis of efficacy. Primary metronidazole and clarithromycin resistance were observed in 84% and 8% of study patients, respectively. One month after the end of therapy, H. pylori infection was cured in 40 of 51 patients (78%); 95% confidence interval, (65%-89%). The triple-therapy regimen was well-tolerated, with only 2 patients (4%) requiring premature withdrawal from the study due to treatment-related adverse events. Taste perversion (15.0%) and diarrhea (11.7%) were the most frequently reported adverse events possibly or probably related to study medication during the treatment period. CONCLUSION: Despite a high prevalence of metronidazole resistance, a 1-week, triple-drug combination of lansoprazole, clarithromycin, and metronidazole is effective treatment for and well-tolerated by patients with H. pylori infection.
Subject(s)
Clarithromycin/therapeutic use , Drug Therapy, Combination/therapeutic use , Enzyme Inhibitors/therapeutic use , Helicobacter Infections/drug therapy , Helicobacter pylori , Metronidazole/therapeutic use , Omeprazole/analogs & derivatives , 2-Pyridinylmethylsulfinylbenzimidazoles , Adult , Aged , Clarithromycin/administration & dosage , Clarithromycin/adverse effects , Diarrhea/chemically induced , Drug Administration Schedule , Drug Evaluation , Drug Resistance, Microbial , Drug Therapy, Combination/administration & dosage , Drug Therapy, Combination/adverse effects , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/adverse effects , Female , Gastrointestinal Diseases/chemically induced , Helicobacter pylori/drug effects , Humans , Lansoprazole , Male , Metronidazole/administration & dosage , Metronidazole/adverse effects , Middle Aged , Omeprazole/administration & dosage , Omeprazole/adverse effects , Omeprazole/therapeutic use , Safety , Taste Disorders/chemically induced , Treatment OutcomeABSTRACT
Erythromycin is often overlooked for the treatment of skin and skin structure infections. We evaluated the efficacy and safety of erythromycin particles in tablets and of cefadroxil in 164 patients with skin infections; both treatments were given as 500 mg twice daily. One hundred percent of erythromycin and 96% of cefadroxil patients were clinically cured or improved, and 98% of susceptible pathogens were eradicated in both groups. Only three erythromycin patients and one cefadroxil patient left the study early because of GI-related adverse events. Erythromycin, therefore, was as effective and safe as cefadroxil in the treatment of mild-to-moderate skin infections.
Subject(s)
Cefadroxil/therapeutic use , Erythromycin/therapeutic use , Staphylococcal Skin Infections/drug therapy , Adolescent , Adult , Double-Blind Method , HumansABSTRACT
OBJECTIVE: The efficacy and safety of dual and triple therapies with a proton pump inhibitor and antibiotic(s) for therapy of Helicobacter pylori-associated duodenal ulcer disease have been compared using results from independent studies using different methods and regimens, making interpretation difficult. In a large, double-blind, multicenter study conducted in the United States, we compared a triple therapy regimen with four dual therapy and one monotherapy regimens in the eradication of H. pylori and the prevention of ulcer recurrence. METHODS: Patients with active duodenal ulcer disease or history of duodenal ulcer disease within the past year and H. pylori infection were randomized to receive one of six 14-day treatment regimens: lansoprazole 30 mg, clarithromycin 500 mg, and amoxicillin 1 gm b.i.d.; lansoprazole 30 mg b.id. and either clarithromycin 500 mg b.i.d. or t.i.d.; lansoprazole 30 mg b.i.d. or t.i.d. with amoxicillin 1 gm t.i.d.; or lansoprazole 30 mg t.i.d. alone. No additional acid suppression therapy followed eradication therapy. Primary efficacy endpoints were eradication of H. pylori and ulcer recurrence. RESULTS: Of 396 patients enrolled in the study, 352 met the entry criteria for duodenal ulcer status and H. pylori positivity. At 4-6 wk after the end of therapy, H. pylori was eradicated from 94% (44 of 47) of patients receiving lansoprazole, clarithromycin, and amoxicillin triple therapy, 77% (39 of 51) of those receiving lansoprazole t.i.d./amoxicillin t.i.d., 75% (36 of 48) of those receiving lansoprazole b.i.d./clarithromycin t.i.d., 57% (28 of 49) of those receiving lansoprazole b.i.d./clarithromycin b.i.d., 53% (26 of 49) of those receiving lansoprazole b.i.d./amoxicillin t.i.d., and 2% (1 of 53) of those receiving lansoprazole monotherapy (p < or = 0.05, triple therapy vs each dual therapy and each dual therapy vs monotherapy). Of those patients who were documented as free of ulcer at 4-6 wk after treatment, ulcers recurred within 6 months in 7% of patients receiving triple therapy, as compared with 13-23% of patients receiving dual therapy, and 69% of patients receiving lansoprazole monotherapy. Patients who were H. pylori negative at 4-6 wk after treatment were less likely to have an ulcer recurrence than were patients who were H. pylori positive (11% [10 of 95] vs 47% [20 of 43], respectively, across treatment groups). For triple therapy and dual therapy, a similar proportion of patients reported a drug-related adverse event (23% vs 17-33%, respectively). CONCLUSIONS: In patients with active or a recent history of duodenal ulcer, a 14-day course of lansoprazole-based triple therapy without additional acid suppression therapy is highly effective in the eradication of H. pylori and in preventing ulcer recurrence. Among the dual therapies, higher eradication rates occurred when lansoprazole (with amoxicillin) or clarithromycin (with lansoprazole) was administered t.i.d. vs b.i.d., but the rates were still significantly lower than with lansoprazole triple therapy with all three drugs administered b.i.d.
Subject(s)
Amoxicillin/administration & dosage , Anti-Bacterial Agents/administration & dosage , Anti-Ulcer Agents/administration & dosage , Clarithromycin/administration & dosage , Duodenal Ulcer/drug therapy , Helicobacter Infections/drug therapy , Helicobacter pylori , Omeprazole/analogs & derivatives , Penicillins/administration & dosage , 2-Pyridinylmethylsulfinylbenzimidazoles , Adolescent , Double-Blind Method , Drug Administration Schedule , Drug Therapy, Combination , Duodenal Ulcer/prevention & control , Helicobacter pylori/drug effects , Helicobacter pylori/isolation & purification , Humans , Lansoprazole , Omeprazole/administration & dosage , RecurrenceABSTRACT
BACKGROUND: Data submitted to the FDA were reviewed to analyze the relationship between Helicobacter pylori infection and the incidence of early duodenal ulcers, within 6 weeks, following treatment. MATERIALS AND METHODS: Retrospective analyzes were performed on data from three H. pylori development programs submitted to the FDA: ranitidine-bismuth-citrate (RBC), lansoprazole (L) and omeprazole (O). Efficacy assessments for the RBC, L and O programs were made at end of a 4-week treatment period, 4-6 weeks following the end of a 14-day treatment period, and 4 weeks following the end of a 4-week treatment period, respectively. RESULTS: Overall, there was a 15%, 21% and 23% decrease in the number of patients in the RBC, L and O programs, respectively, with ulcers among H. pylori cleared/eradicated patients post-treatment compared with patients with persistent infection. Among patients who did not have cleared/eradicated H. pylori in the RBC and O programs, where antisecretory agents were continued beyond the antimicrobial treatment period, the number of ulcers was lower in the antisecretory plus antimicrobial subgroups compared with the antimicrobial alone subgroups (37% vs. 46% for RBC and 33% vs. 42% for O). Among patients with cleared/eradicated H. pylori, the number of patients with ulcers in the antimicrobial alone subgroups and antisecretory plus antimicrobial subgroups were similar within each program. Antimicrobials alone had significantly lower rates of ulcers among patients with cleared/eradicated H. pylori as compared with patients without clearance/eradication. CONCLUSIONS: The early incidence of duodenal ulcers is significantly decreased in patients with H. pylori clearance/eradication.
Subject(s)
Anti-Infective Agents/therapeutic use , Anti-Ulcer Agents/therapeutic use , Duodenal Ulcer/prevention & control , Helicobacter Infections/drug therapy , 2-Pyridinylmethylsulfinylbenzimidazoles , Bismuth/therapeutic use , Clinical Trials as Topic , Follow-Up Studies , Humans , Lansoprazole , Odds Ratio , Omeprazole/analogs & derivatives , Omeprazole/therapeutic use , Ranitidine/analogs & derivatives , Ranitidine/therapeutic use , Research Design , Retrospective Studies , United States , United States Food and Drug AdministrationABSTRACT
BACKGROUND: Omeprazole is known to have an effect on Helicobacter pylori in vivo. One opinion is that H. pylori "migrates" from the antrum to the corpus in response to omeprazole therapy. METHODS: To determine whether H. pylori migrates in response to omeprazole, we assessed the presence of H. pylori in the antrum and corpus in duodenal ulcer patients receiving omeprazole for 4 wk. Culture and histological examination of antral biopsies (Genta stain) were performed before patients received omeprazole, at the end of therapy, and 4-6 wk later. The end points were presence or absence of H. pylori and the number of H. pylori colonies per biopsy. RESULTS: Seventy-two patients had H. pylori in both the antrum and corpus at entry and 4-6 wk after ending therapy. Three general patterns were prevalent at the end of omeprazole therapy: antrum- and corpus-positive (54%), antrum-negative and corpus-positive (24%), both antrum- and corpus-negative (21%), and one patient had antrum-positive with corpus-negative (1%). Evaluation of the number of colonies per biopsy in those who remained H. pylori-positive in both the antrum and corpus throughout showed that the number of H. pylori decreased in both the antrum and corpus during therapy (507 +/- 60 vs. 225 +/- 51, p < 0.01 and 415 +/- 58 vs. 290 +/- 46 0.1) for antrum and corpus, respectively, and tended to return to pre-therapy levels 4-6 wk later. The number of H. pylori in the corpus also decreased in the antrum-negative and corpus-positive group during therapy with omeprazole (433 +/- 87 vs. 185 +/- 61, p < 0.05). In most of the patients studied, the number of H. pylori in the corpus was less posttreatment than it was pretreatment. The decrease in H. pylori load was also reflected in the development of false-negative urea breath tests. CONCLUSIONS: Omeprazole is detrimental to H. pylori in both the antrum and the corpus; migration from the antrum to the corpus in response to omeprazole is a myth.
Subject(s)
Anti-Ulcer Agents/therapeutic use , Duodenal Ulcer/drug therapy , Duodenal Ulcer/microbiology , Helicobacter Infections/drug therapy , Helicobacter pylori/drug effects , Omeprazole/therapeutic use , Pyloric Antrum/microbiology , Stomach/microbiology , Biopsy , Colony Count, Microbial , Helicobacter Infections/microbiology , Helicobacter pylori/growth & development , Humans , Time FactorsABSTRACT
UNLABELLED: Current regimens to eradicate Helicobacter pylori usually consist of metronidazole plus a bismuth compound, as well as a third agent such as tetracycline. Such regimens are not ideal because organisms may be metronidazole-resistant, side-effects occur, and compliance is often poor. This randomized, double-blind study was designed to assess the ability of clarithromycin, a new macrolide antimicrobial, as monotherapy to eradicate H. pylori. Thirty-seven healthy volunteers who were H. pylori positive by 13C-urea breath test plus histology and/or culture completed 14 days of oral therapy with clarithromycin in one of three dosages. Eradication, defined as all three tests negative at 4-6 wk after the end of therapy, was achieved in 2/13 (15%) with clarithromycin 500 mg bid, 4/11 (36%) with 1000 mg bid, and 7/13 (54%) with 500 mg qid. Isolates of H. pylori were resistant to clarithromycin prior to therapy in 12% of subjects, and became resistant during therapy in 21% of subjects. Taste perversion, the most common side effect, resulted in one subject terminating therapy. CONCLUSIONS: Whereas clarithromycin is a promising antimicrobial in the eradication of H. pylori, it is not sufficient to be used as monotherapy.