Sodium cromoglycate in asthma: correlation between response and serum concentrations.

The clinical response to sodium cromoglycate treatment was compared with its concentration in serum. Twenty five children with asthma entered a 10 week trial of two baseline weeks followed by eight weeks of treatment by the inhalation of 20 mg of sodium cromoglycate spincaps four times a day. Individual clinical response was determined by the differences between baseline and treatment periods of: (a) percentage of symptomless days (delta score 0); (b) diary derived daily score for four symptoms (delta DS); and (c) peak expiratory flow rate (delta PEFR). At the end of the treatment period, patients inhaled a 20 mg spincap of sodium cromoglycate and the technique of inhalation was graded. Concentrations of sodium cromoglycate in serum were measured by radioimmunoassay in samples withdrawn 5 to 120 minutes after inhalation. Delta Score 0, delta DS, and delta PEFR correlated significantly with the area under the concentration time curve. Both the area under the sodium cromoglycate concentration time curve and clinical response correlated significantly with inhalation technique score. We suggest that response of children with asthma to inhalation treatment with sodium cromoglycate is correlated to its serum concentrations.