Role for 5‑day, once-daily extended-release clarithromycin in acute bacterial exacerbation of chronic bronchitis

ABSTRACT Background: Clarithromycin is commonly dosed for 7 or more days in patients with acute bacterial exacerbation of chronic bronchitis (ABECB). Studies with other antibiotics have shown equivalent efficacy, reduced/similar frequency of adverse events, improved adherence and patient satisfaction, and lower treatment costs with a shorter treatment course. Patients and methods: The study population was derived from two multicenter, randomized, double-blind (North America)/single-blind (France) comparative trials in which outpatients at least 35 years old with a presumptive diagnosis of obstructive ABECB were randomized to receive clarithromycin extended-release (ER) 1000 mg once daily for 5 days or a comparator agent – clarithromycin immediate-release (IR) 500 mg twice daily for 7 days (in North America) or telithromycin 800 mg once daily for 5 days (in France). Results: A total of 818 patients were randomized (411 to clarithromycin ER and 407 to a comparator agent). The clinical cure rate in clinically evaluable patients at the follow-up visit was 90% each for the clarithromycin ER group (318/353) and the comparator group (318/355). The patient bacteriological cure rate and the overall target pathogen eradication rate in clinically and bacteriologically evaluable patients were each 92% for the clarithromycin ER group (155/168 and 189/205, respectively) and 93% for the comparator group (147/158 and 183/197, respectively) at the follow-up visit. The study drugs were generally well tolerated, with < 2% of patients discontinuing their treatment prematurely due to a drug-related adverse event. The incidence of drug-related adverse events was 18% (73/411) in the clarithromycin ER group and 24% (97/407) in the comparator group. Clarithromycin ER-treated patients reported statistically significantly fewer episodes of abdominal pain than did patients treated with a comparator agent (0.2% vs. 1.7%, respectively; p = 0.037). This combined analysis is limited by differing blinding methods, comparator agents, and their duration of administration. Furthermore, many patients were excluded from the clinically and bacteriologically evaluable group due to lack of a pretreatment target pathogen. Conclusion: A once daily, 5‑day clarithromycin ER regimen appears to be a suitable choice for treating patients with ABECB.