Do not take Labeta Inj - 20Mg/4Ml if you are allergic to any of its contents; if you have heart diseases like heart block or sick sinus syndrome (unless you have a pacemaker), heart failure or cardiogenic shock, ongoing low blood pressure, extremely slow heart rate, Prinzmetal angina, asthma or obstructive airway disease, or phaeochromocytoma (tumour of the adrenal gland). Inform your doctor if you have peripheral vascular disease (Raynaud's syndrome or intermittent claudication), diabetes, overactive thyroid, metabolic acidosis, respiratory system problems, heart, kidney or liver problems. Labeta Inj - 20Mg/4Ml should not be given to children and adolescents below 18 years. Consult your doctor if you are pregnant or breastfeeding.