Reflections on the mechanism(s) of action of sodium cromoglycate (Intal) and the role of mast cells in asthma.

In this review, only a few questions concerning the mechanism(s) of action of sodium cromoglycate in asthma have been considered. The large number of cells and mediator pathways where sodium cromoglycate may have pharmacological effects are depicted. In addition to its mast cell effect, sodium cromoglycate is also inhibitory to macrophages, eosinophils, monocytes and platelets, which are all important components in the inflammatory response of asthma. From studies with bradykinin and sulphur dioxide it is also known that the drug can block afferent discharges along non-myelinated nerves. Although the ability of sodium cromoglycate to block late phase responses and acquired hyper-reactivity is not questioned, to what extent its therapeutic efficacy can be accounted for by actions on these leukocytes and reflex pathways is not known. When administered to patients with asthma, sodium cromoglycate results in symptomatic improvement, but there is still much to be learned about its mode of action.