Abstract

The tetracyclines are effective antibiotics for the treatment of exacerbations of chronic bronchitis and are also extensively used for the long-term treatment of acne vulgaris. Their more general use has, however, diminished because of an increasing incidence of tetracycline resistance among many formerly susceptible bacteria and because their effects on developing teeth contraindicate their use in pregnancy and childhood. Moreover in patients with pyelonephritis tetracyclines may further impair renal function.¹ New tetracyclines are of special interest if they have any advantage over existing preparations in these respects.