Pharmacology of disodium cromoglycate.

When given before exposure to an allergen, cromoglycate (DSCG) inhibits immediate and late bronchoconstriction after allergen inhalation. DSCG inhibits exercise- and SO2-induced bronchoconstriction and probably also has a soothing effect on vago-vagal reflexes which cause bronchospasms deriving from irritant receptors of the lung. DSCG given for a long period of time reduces bronchial hyperreactivity, i.e. readiness for asthma in general (the crucial dosage of histamine able to induce asthma increases). Bronchial hyperreactivity is caused by viral infections, late allergic reactions, irritating chemicals such as SO2, betablockers, alphastimulants and increased vagal efferent activity. Betastimulants, anticholinergics and anti-SRS do not reduce hyperreactivity in the long run; only DSCG and corticosteroids are effective.