The drug therapy of asthma: directions for the 21st century.

There are several novel pharmacological approaches to asthma therapy which have resulted from a further understanding of airway smooth muscle function and inflammatory mechanisms involved in asthma. The most effective bronchodilators currently available are beta 2-adrenoceptor agonists and drugs with a prolonged duration of action after inhalation will be useful. Other possible bronchodilator approaches include vasoactive intestinal peptide, prostaglandins, novel xanthines, selective muscarinic antagonists, drugs interfering with intracellular calcium release and K+-channel activators. The most effective anti-inflammatory treatment is corticosteroids and efforts are being made to improve the topical potency of these drugs. Many other ways of reducing inflammatory effects in asthma are being explored, such as mediator antagonists (especially thromboxane and PAF antagonists), inhibitors of inflammatory cell activation (especially of eosinophils) and inhibition of neurogenic inflammation. Use of anti-inflammatory therapies earlier in the disease should become more widespread.