[Pharmacologic therapy of bronchial asthma]

The main feature in asthma is bronchial eosinophilic inflammation, induced, in genetically predisposed subjects, by known (aeroallergens, viral infection, occupational agents) and unknown agents. Inflammation critically increases bronchial responsiveness so that even rather mild stimuli (exercise, cold air, mist, allergens) are able to induce obstructive reactions. When preventive measures (specific immunotherapy, avoidance of inflammatory and precipitating factors) are inadequate, a pharmacological treatment is necessary. This should, in addition relieve bronchospasm, neutralize precipitating factors and reduce inflammation. In the first case bronchospasmolytic antireactive agents (beta 2-stimulants, antimuscarinic agents, theophyllines) should be used, whereas, in the second case, the first choice drugs are corticosteroids. Chromon derivatives can also be considered for both their antireactive and antiflogistic effects. It is impossible to elaborate rigid therapeutic schemes. Therapy must be individualized on the basis of symptoms, objective physical signs and functional data. Drugs, except theophylline (for which slow release oral formulations are preferred), should be preferably administered by inhalation. For patients who cannot properly master the use of metered dose inhalers, spacer devices or dry powder inhalers are indicated. Whereas mild asthmatic forms can be treated without corticosteroids, these are absolutely necessary when bronchospasmolytics and chromon derivatives, although appropriately used, do not provide a satisfactory control of the asthmatic syndrome. Many other drugs are now under study (antileukotrienes, anti-PAF, anti-5-lipoxygenase, anti-phospholipase A2), but the results published so far do not seem very promising. Anti-histamines, calcium antagonists, alpha-blocking drugs are justified only in some circumstances. The antireactive activity of loop diuretics is interesting, but its real therapeutic value is still to be assessed. Antibiotics are only needed in the (rare) cases of worsening of asthmatic symptoms due to infective sensitive agents.