Electrolyes -- Calcium ====================== POLICY NUMBER: X - 13 Page 1 of 2 UPMC MERCY DEPARTMENT OF PHARMACEUTICAL SERVICES ______________________________________________________________________ POLICIES AND PROCEDURES ____________________________________________________________ Subject: PARENTERAL CALCIUM REPLACEMENT GUIDELINES IN ADULT PATIENTS Rationale: The use of calcium replacement products may easily lead to errors by physicians, pharmacists and nurses if detail is not emphasized. There are two intravenous calcium preparations on the Formulary, with differing safety and efficacy profiles. Extravasations with both calcium chloride and calcium gluconate have been documented with outcomes often leading to extensive morbidity secondary to local pain, edema, and induration, progressing to calcinosis cutis or formation of deep necrotic lesions. Tissue necrosis is more common with calcium chloride. Purpose: To standardize prescribing, preparation and administration of parenteral calcium replacement products to better ensure safety of patients. Procedure: 1. All orders for parenteral calcium replacement therapy must be ordered in units of the salt form. For example. 2. Intravenous Calcium Gluconate a. Calcium gluconate is the ONLY parenteral calcium salt appropriate for the treatment of asymptomatic hypocalcemia. b. The ONLY intravenous calcium to be used in a non-Critical Care area under normal circumstances. c. Should be given by IV infusion. 3. Intravenous Calcium Chloride a. May be given IV push in Critical Care or on all patient care areas during RRTs or in emergency situations. b. Should be given through a central line unless in an emergency situation. c. Appropriate indications for calcium chloride administration include symptomatic hypocalcemia, symptomatic hyperkalemia, symptomatic hypermagnesemia, calcium channel blocker overdose, toxicity or prevention of calcium channel blocker associated hypotension, and emergency situations requiring immediate onset of calcium therapy. d. Calcium chloride is NOT indicated for asymptomatic hypocalcemia (exception see point e.) e. Calcium chloride may be used in the treatment of symptomatic and/or asymptomatic hypocalcemia in patients with end-stage liver disease. 4. Intravenous Administration a. The forearm is the ideal peripheral venipuncture site for administration of parenteral calcium, provided good access is available. Calcium should only be given with extreme caution through a hand, foot, finger, scalp or joint vein or any area over a bony prominence. This is especially true for patients with poor peripheral circulation. b. Larger gauge needles are preferred for all parenteral calcium administration (preferably 20 gauge or larger). c. The patency of the IV must be assessed prior to administration of IV calcium by checking for blood return. 5. The preferred treatments of calcium extravasations can be found on Mercynet under clinical reference. (http://mercynet.pmhs.org/docs/extravguide2010.pdf) þ CaCl2 vs. Ca Gluconate the extravasation of calcium chloride more frequently progresses to tissue necrosis and a more adverse outcome. Another difference between the products is that calcium gluconate requires cleaving of the gluconate salt before calcium is available as free, ionized, cardiovascularly-active calcium. Calcium chloride is available immediately as free ionized calcium. The guidelines call for calcium gluconate to be used for the treatment of asymptomatic hypocalcemia. Calcium chloride may be used only in emergency situations such as the treatment of symptomatic hyperkalemia, symptomatic hypermagnesemia, calcium channel blocker overdosage, toxicity or prevention of calcium channel blocker associated hypotension. Calcium chloride may also be used for calcium replacement (emergency and non-emergency) in end-stage liver disease. The cleaving of the gluconate salt of calcium gluconate occurs in the liver and in endstage liver disease this cleaving does not occur. It should be noted that calcium chloride contains approximately 2 and a half the amount of calcium that calcium gluconate contains. þ Calcium Metabolism - fractional excretion of Ca++ liess than 1% - about 50% of calcium is bound to plasma proteins - 1.0 mmol = 4 mg% (4 mg/dL) - PTH causes: + increased Ca++ and PO4-- via effects on bone and intestine + increased Ca++ and DEcreased PO4-- via effects on kidney + increased 1,25 DHCC (vitamin D) in the kidney, that then causes increased absorption in the gut. - Calcitonin (after a large calcium load in the gut) causes + decreased Ca++ and PO4-- via effects on bone. - Vitamin D causes: + increased Ca++ and PO4-- via effects on both intestine and bone + vitamin D metabolism: - cholesterol absorbed in gut - in skin, changed to the 7-dehydro form - in liver, converted to 25-dehydro form - in kidney, converted to the most active 1,25 dehydrocholecalciferol (1,25 DHCC) þ Calcium Levels - with normal albumin and globulin concentrations: Ionized calcium = Total calcium - (0.8 x Total protein). Protein is in g/dL and calcium is in mg/dL - with abnormal albumin and globulin concentrations: Ionized calcium = Total calcium - (1.1 x albumin) - (0.2 x globulin) where albumin is in g/dL and calcium is in mg/dL. --Tintinalli, 3rd ed. p74 þ Hypocalcemia - Cimetidine lowers serum calcium levels, either by decreasing the synthesis or the secretion of parathyroid hormone. Therefore, it should not be used in patients with hypocalcemia. Reference: Tintinalli 3rd ed. p 75 - Hypocalcemia in rhabdomyolysis þ Hypercalcemia - factitious hypercalcemia can be caused by a tourniquet on the arm for a long time for blood draws.