Abstract

The British National Formulary lists 27 insulin preparations¹ which now include the first of the new ‘human’ insulins. The insulins differ in their structure, purity, potency, pH and physical state. These affect the speed of onset and duration of action of the different preparations and also help explain the variations in response that may occur in any one patient and between different patients. The profusion of preparations means that it is no longer possible to have a thorough working knowledge of each formulation. In this article we discuss the differences and suggest ways of simplifying the choice.