Asthma/chemically induced; Asthma/drug therapy; Bronchoconstrictor Agents/adverse effects; Bronchodilator Agents/administration & dosage; Bronchodilator Agents/adverse effects; Pulmonary Disease, Chronic Obstructive/drug therapy; Adrenergic beta-Agonists/administration & dosage; Adrenergic beta-Agonists/adverse effects; Adult; Anti-Infective Agents, Local/administration & dosage; Anti-Infective Agents, Local/adverse effects; Asthma/epidemiology; Benzalkonium Compounds/administration & dosage; Benzalkonium Compounds/adverse effects; Bronchoconstrictor Agents/administration & dosage; Chlorofluorocarbons/administration & dosage; Chlorofluorocarbons/adverse effects; Cholinergic Antagonists/administration & dosage; Cholinergic Antagonists/adverse effects; Clinical Trials, Phase II as Topic; Cross-Over Studies; Double-Blind Method; Drug Combinations; Edetic Acid/administration & dosage; Edetic Acid/adverse effects; Equipment Design; Female; Humans; Incidence; Male; Metered Dose Inhalers; Middle Aged; Randomized Controlled Trials as Topic; Retrospective Studies