Monitor patients w/ cardiac arrhythmias especially 3rd-degree AV-block & tachyarrhythmias (accelerated &/or irregular heartbeat), idiopathic subvalvular aortic stenosis, hypertrophic obstructive cardiomyopathy, severe heart disease particularly acute MI, ischemic heart disease, CHF, occlusive vascular diseases particularly arteriosclerosis, arterial HTN & aneurysm. Known or suspected QTc interval prolongation (>0.44 sec); thyrotoxicosis, DM, pheochromocytoma, untreated hypokalemia; active or quiescent pulmonary TB, fungal & viral airway infections. Severe or unstable asthma; serious asthma-related adverse effects & exacerbations. Do not start during exacerbation or significantly worsening or acutely deteriorating asthma. Medically assess patients w/ sudden & progressive deterioration in control of asthma or COPD. Paradoxical bronchospasm may occur. Monitor K & glucose levels. Concomitant treatment w/ xanthine derivatives, steroids & diuretics. Do not administer for at least 12 hr before halogenated anesth. Use the lowest effective dose. Systemic effects may occur at high doses used for long periods. Avoid abrupt w/drawal. Pregnancy & lactation. Childn & adolescents <18 yr.