Prn Budesonide/Formoterol Versus Regular Budesonide/Formoterol Plus Prn Terbutaline in Mild-Moderate Asthma

Inclusion Criteria: * Male or female out-patient aged from 18 years to 65 years * Clinical diagnosis of moderate persistent asthma for at least 6 months, according to GINA revised version 2006 guidelines * Post-bronchodilator forced expiratory volume (FEV1) at least 80% of the predicted * Either positive methacholine challenge test (PC20 FEV1\< 4mg/ml or PD20 FEV1\<0.8 mg) or positive response to the reversibility test in the last year * Asthma either not adequately controlled with low-dose (≤500 mcg beclomethasone or equivalent) inhaled corticosteroids (ICS) or controlled by bid inhaled combination of low-dose ICS/long acting beta-2 agonists (LABA) * A co-operative attitude and ability to be trained to correctly use the dry powder inhalator and to complete the diary cards * Written informed consent obtained Exclusion Criteria: * Inability to carry out pulmonary function testing * Moderate severe asthma associated with reduced lung function * History of near-fatal asthma and/or admission intensive care unit because of asthma * 3 or more courses of oral corticosteroids or hospitalization for asthma during the previous year * Diagnosis of COPD as defined by the GOLD guidelines * Evidence of severe asthma exacerbation or symptomatic infection of the airways in the previous 8 weeks * Current smokers or recent (less than one year) ex-smokers, defined as smoking at least 10 pack/years * History or current evidence of heart failure, coronary artery disease, myocardial infarction, severe hypertension, or cardiac arrhythmias * Diabetes mellitis * Percutaneous transluminal coronary angioplasty (PTCA) or coronary artery by-pass graft (CABG) during the previous six months * Abnormal ECG * Clinically significant or unstable concurrent diseases: uncontrolled hyperthyroidism, significant hepatic impairment, poorly controlled pulmonary disease (tuberculosis, active mycotic infection of the lung), gastrointestinal (e.g., active peptic ulcer), neurological or haematological autoimmune diseases * Malignancy * Any chronic diseases with prognosis \< 2 years * Pregnant or lactating females or not able to exclude pregnancy during the study period * History of alcohol or drug abuse * Patients treated with monoamine oxidase inhibitors, tricyclic antidepressants or beta-blockers as regular use * Allergy, sensitivity or intolerance to study drugs and/or study drug formulation ingredients * Patients unlikely to comply with the protocol or unable to understand the nature, scope and possible consequences of the study * Patients who received any investigational new drug within the last 12 weeks * Patients who have been previously enrolled in this study