The management of asthma involves prophylactic measures to reduce inflammation and airway resistance and to maintain airflow and specific regimens for the treatment of acute attacks. Lung function measurement is important in determining treatment thus, peak flow monitoring is encouraged. If usual relief is diminished or the duration of action is reduced, patients are warned not to increase the dose or frequency of administration but seek medical advice. Salbutamol should be given with caution in hyperthyroidism, myocardial insufficiency, arrhythmias, susceptibility to QT-interval prolongation, hypertension and diabetes mellitus. In severe asthma, particular precaution is required to avoid inducing hypokalemia as this effect may be potentiated by hypoxia or by concomitant administration of other anti-asthma drugs. Plasma potassium concentrations should be monitored.