Sodium cromoglycate in chronic asthma.

A long-term double-blind trial of sodium cromoglycate (SCG) with and without isoprenaline, with a placebo control, was undertaken in Edinburgh to a similar design as a previously reported trial in London. The results from the two centres were compared and combined. In Edinburgh 41 patients were studied for 36 weeks and 40 for 52 weeks and in the combined series 121 were studied for 36 weeks and 114 for 52 weeks. In the second year 14 patients were followed-up in Edinburgh and 27 in London. The two SCG regimens were superior overall to placebo both in the Edinburgh and London patients. SCG was effective in similar proportions of patients with extrinsic and intrinsic asthma. In the second year the effectiveness of SCG was further tested by randomly allocating half the patients to a placebo. Some patients derived a continuing benefit from SCG, but its continued use did not appear to be necessary for others, whose progress on placebo was satisfactory.