Abstract

Most exacerbations of chronic bronchitis are effectively treated either by tetracycline or by ampicillin in the conventional dose of 250 mg 6-hourly for 7 days. Used in this way ampicillin has no advantage over tetracycline.¹ However even continuous treatment with either drug fails to prevent relapses in some patients. This seemed surprising since low concentrations of ampicillin are bactericidal to Haemophilus influenzae, the commonest pathogen in chronic bronchitis. The explanation appears to be that even doses of 500 mg 6-hourly only achieve inhibitory concentrations in the sputum.² Larger doses were therefore tried,^{3, 4} and are being advocated by the manufacturer (Beecham).