Use caution in history of severe anaphylaxis to allergens. Hypotension is common. Extravasation can lead to skin necrosis and sloughing. In general, patients with bronchospastic disease should not receive β-blockers (esmolol, with β~1~ selectivity, has been used cautiously). Consider pre-existing conditions such as sick sinus syndrome before initiating. Use with caution in the following cases: diabetes mellitus (may potentiate hypoglycemia and/or mask signs and symptoms), in compensated heart failure, in myasthenia gravis, in peripheral vascular disease (including Raynaud’s), in history of psychiatric illness (may cause or exacerbate CNS depression), or in renal impairment (active metabolite retained). Use with caution in patients on concurrent verapamil or diltiazem (bradycardia or heart block can occur). Adequate α-blockade is required prior to use of any β-blocker in untreated pheochromocytoma. Concentrations >10 mg/mL or infusion into small veins or through a butterfly catheter should be avoided (can cause thrombophlebitis). β-Blocker therapy should not be withdrawn abruptly (particularly in CAD). Do not use in treatment of hypertension associated with vasoconstriction related to hypothermia. Caution in history of severe anaphylaxis to allergens, diabetes mellitus, compensated heart failure, sick sinus syndrome, myasthenia gravis, peripheral vascular disease (Raynaud’s), history of psychiatric illness, renal impairment or with verapamil or diltiazem (avoid I.V.). Avoid in bronchospastic disease or in hypertension with vasoconstriction related to hypothermia. Adequate α-blockade prior to use. Do not withdraw abruptly (CAD).