Hypomagnesemia & Hypermagnesemia (1 of 3) HYPOMAGNESEMIA 1 Hospitalized patient presents w/ signs & symptoms of hypomagnesemia 2 DETERMINE UNDERLYING CAUSE & MG LEVELS Mg >0.7 mmol/L Mg <0.7 mmol/L (1.8 mg/dL) (1.8 mg/dL) 3 ALTERNATIVE DIAGNOSIS CLASSIFY SEVERITY Moderate- Mild OF Mg DEPLETION severe Mg PO REPLACEMENT Mg IV REPLACEMENT 1 SIGNS & SYMPTOMS OF HYPOMAGNESEMIA • Hypomagnesemia has a serum magnesium concentration of <1.3 mEq/L Neuromuscular CV Metabolic • Muscle weakness • Prolonged PR & QT intervals • Hyperinsulinism • Ataxia & vertigo • Cardiac arrhythmias • Carbohydrate intolerance • Trousseau & Chvostek signs • Atherosclerosis • Carpopedal spasm • Hypocalcemia • Depression, psychosis • Osteoporosis & osteomalacia • Seizures 2 CAUSES OF HYPOMAGNESEMIA Increased Intestinal Drugs Increased Renal Metabolic Losses • Diuretics Excretion • DM • Vomiting, diarrhea • Aminoglycosides • Volume expansion • Hypoparathyroidism • Prolonged • Cisplatin • Hypercalcemia & • Primary nasogastric suction • Alcohol hypercalciuria hyperparathyroidism • Extensive bowel • Pentamidine • Osmotic diuresis • Primary resection • Ciclosporin • Renal disease w/ Mg aldosteronism • Malabsorption • Amphotericin B wasting • Phosphate depletion syndromes • Renal transplant • Hyperthyroidism • Severe malnutrition • Treatment of • Steatorrhoea ketoacidosis • Acute pancreatitis • Hungry bone • Intestinal fi stula syndrome • Ileitis, colitis 3 SEVERITY OF MAGNESIUM DEPLETION Mild Hypomagnesemia Moderate-Severe Hypomagnesemia • Patient is© usually asymptomatic MIMS• Patient is usually symptomatic • Serum Mg is usually >0.5 mmol/L (1.2 mg/dL) • Serum Mg is usually <0.5 mmol/L (1.2 mg/dL) Not all products are available or approved for above use in all countries. Specifi c prescribing information may be found in the latest MIMS. B1 © MIMS 2019 Hypomagnesemia & Hypermagnesemia (2 of 3) HYPERMAGNESEMIA 1 Hospitalized patient presents w/ signs & symptoms of hypermagnesemia HYPO- & HYPERMAGNESEMIA 2 DIAGNOSIS DETERMINE UNDERLYING Mg <1.3 mmol/L CAUSE & MG LEVELS Mg >1.3 mmol/L (3 mg/dL) (3 mg/dL) ALTERNATIVE TREATMENT DIAGNOSIS • Stop preparation that contains large amt of Mg • Dialysis w/ low Mg bath may be required by patients w/ renal failure Pharmacological therapy In severe hypermagnesemia w/ life-threatening complications: • Ca (IV) 1 SIGNS & SYMPTOMS OF HYPERMAGNESEMIA • Hypermagnesemia has a serum magnesium concentration of >2.2 mEq/L Signs & Symptoms • Usually do not appear unless Mg >2 mmol/L (5 mg/dL) • Depressed respiration & apnea • Hypotension • Depressed mental status • Bradycardia • Disappearance of deep tendon refl exes • Complete heart block & cardiac arrest • Muscular weakness • ECG abnormalities • Paralysis • Drowsiness 2 CAUSES OF HYPERMAGNESEMIA Rarely occurs & is usually iatrogenic • Patient w/ renal failure receiving Mg-containing • Volume depletion antacid, laxative or infusion • Familial hypocalciuric hypercalcemia • Untreated ketoacidosis • Adrenal insuffi ciency (AI) • Acute renal failure (ARF) w/ rhabdomyolysis • Hypothyroidism • Lithium© MIMS Not all products are available or approved for above use in all countries. Specifi c prescribing information may be found in the latest MIMS. B2 © MIMS 2019 Hypomagnesemia & Hypermagnesemia (3 of 3) Dosage Guidelines CALCIUM (IV) Ca Content Drug Available Dosage/Remarks mg/g mEq/g Strength Calcium 273 13.6 10% inj soln 100-200 mg elemental Ca IV over 5-10 min HYPO- & HYPERMAGNESEMIA chloride [27.3 mg • Antagonizes toxic eff ects of Mg (1.36 mEq) Adverse Reactions Ca/mL] • Irritation at inj site. Ca chloride is the most irritating Calcium 82 4.1 22% inj soln - May cause gangrene if extravasation occurs • gluceptate [18 mg Hypercalcemia which is more likely in renal failure patients & those supplemented w/ Vit D (0.9 mEq) • Rapid IV inj may cause CV eff ects (vasodilation, Ca/mL] decreased BP, bradycardia, arrhythmias, myocardial infarction) Calcium 89 4.5 10% inj soln • GI eff ects (GI irritation, constipation), renal calculi gluconate [8.9 mg Special Instructions (0.45 mEq) • Infuse slowly not to exceed 0.7-1.8 mEq/min • Ca/mL] CaCl2 should not be used if metabolic acidosis is present MAGNESIUM Ca Content Drug Available Dosage/Remarks mg/g mEq/g Strength Magnesium 59 4.8 Various oral Parenteral replacement: gluconate strengths are Severe hypomagnesemia: available 16 mEq IV over 10 min followed by 4 mEq/hr IV continuous infusion or 8-16 mEq IV 4 hrly Magnesium 120 9.9 No IV access: 8-32 mEq IM 4-6 hrly lactate Renal insuffi ciency: 2 mEq/hr IV continuous infusion Magnesium 111 9 Oral replacement: oxide Severe hypomagnesemia: 30-56 mEq/day PO in divided doses Mild hypomagnesemia: Magnesium 99 8.1 10% inj soln 10-28 mEq/day PO in divided doses sulfate [9.8 mg Adverse Reactions (0.8 mEq) • Hypermagnesemia which is uncommon when Mg/mL] given orally unless there is renal impairment • 50% inj soln GI irritation & watery diarrhea [49 mg Special Instructions • Adjust dose based upon close monitoring of Mg (4 mEq) levels Mg/mL] • Monitor K & Ca levels frequently • Bolus doses are rapidly excreted by the kidneys - Smaller continuous infusions may be a better option All dosage recommendations are for non-pregnant & non-breastfeeding women, & non-elderly adults w/ normal renal & hepatic function unless otherwise stated. ©Not all products areMIMS available or approved for above use in all countries. Products listed above may not be mentioned in the disease management chart but have been placed here based on indications listed in regional manufacturers’ product information. Specifi c prescribing information may be found in the latest MIMS. Please see the end of this section for the reference list. B3 © MIMS 2019.