Insulin glargine is not appropriate for intravenous administration (IV); the prolonged activity of insulin glargine is dependent on injection into subcutaneous tissue. IV administration of the usual subcutaneous dosage could result in severely low blood glucose concentrations. Long-acting insulin preparations should not be used for diabetic ketoacidosis (DKA), hyperosmolar hyperglycemic state (HHS), diabetic coma, or other emergencies requiring rapid onset of insulin action. Several types, routes, and frequencies of administration of insulin have been studied in patients with DKA and HHS; however, the American Diabetes Association recommends that regular insulin (versus the rapid-acting analogs) by continuous intravenous infusion be used to treat these conditions unless they are considered mild. Regular insulin is also preferred for those patients with poor tissue perfusion, shock, or cardiovascular collapse, or in patients requiring insulin for the treatment of hyperkalemia. Insulin glargine should not be used for continuous subcutaneous insulin infusion (CSII) administration; only quick-acting insulins (., regular insulin, insulin lispro, insulin glulisine, and insulin aspart) should be used by this route of administration.