Download Adult Electrolyte Replacement

3 MUSC Medical Center
Pharmacy Services
Title:
Adult Electrolyte Replacement - Pocket Reference Cards
Policy number:
D7
Origin date:
Revised date:
Review date:
Distribution:
P&P References:
6/98
Key Words: electrolyte, replacement, dosing, guidelines, magnesium, phosphorus, phosphate,
potassium
Purpose Statement:
These cards are intended to provide general guidelines for magnesium (Mg)(d07_1.frm),
phosphorus (P) (d07_2.frm), and potassium (K) (d07_3.frm) electrolyte replacement; to identify
oral and parenteral products available at MUSC Medical Center for electrolyte replacement; and
to specify appropriate units of electrolyte content in these products.
Policies and Procedures:
1.
The coordinator of Drug Information or his/her designee will be responsible for printing
and distribution of the adult electrolyte replacement cards.
2.
Additional copies may be obtained by calling the Drug Information Center at extension
2-3896.
3.
The adult electrolyte replacement cards have been approved by MCIG (6/11/98), PLT
(6/18/98), and P&T (6/30/98).
4.
Updating of the adult electrolyte replacement cards will be done on an as needed basis by
the coordinator of Drug Information or his/her designee.
Approval for these revisions will be made by the coordinator of Drug Information. No
further approval process will be needed for these revisions.
5.
The cards will be distributed to the physicians, pharmacists, and adult inpatient nursing
units at MUSC Medical Center. The cards will be available to other health care
professionals at MUSC Medical Center as requested.
6.
The adult electrolyte replacement cards will be included in the MUSC Medical Center
Formulary.
3 Magnesium Replacement in Adults (d07_1.frm)
The normal laboratory range for magnesium is 1.6 - 2.3 mg/dl. For mild hypomagnesemia
(1.3 - 1.5 mg/dl),* oral agents may be used. Oral magnesium-containing agents available or on The
Medical University of South Carolina Formulary of Accepted Drugs include:
Table 1 - MAGNESIUM-CONTAINING ORAL PRODUCTS
Product Name
Elemental Magnesium Content
Magnesium Oxide Tablet 400 mg
(Mag-Ox 400®)
241.3 mg
(20 mEq)
Magnesium Gluconate Tablet 500 mg
(Almora®; Magonate®)
27 mg
(2 mEq)
(Magtrate®)
29 mg
(2 mEq)
Magnesium Gluconate Liquid 1000 mg/5 ml
(Magonate®)
54 mg /5 ml
(4.5 mEq)/5 ml
Magnesium Chloride Sustained Release Tablet
(Slow-Mag®)
64 mg
(5 mEq)
1000 mg Elemental Magnesium = 83.3 mEq = 41.1 mMol
For moderate to severe hypomagnesemia (< 1.3 mg/dl or < 1.6 mg/dl with symptoms),* parenteral
magnesium replacement is generally indicated.
Table 2 - MAGNESIUM-CONTAINING INTRAVENOUS PRODUCT
Product Name
Magnesium Sulfate
50% - (4 mEq/ml)
*Breakpoints arbitrarily assigned.
Elemental Magnesium Content
97.6 mg/1 g MgSO4
(8 mEq)/1 g MgSO4
Use clinical judgment in interpretation for patient specific care.
References
1. Alfrey AC. Normal and abnormal magnesium metabolism. In: Schrier RW., ed. Renal and electrolyte disorders,
5th ed, Philadelphia: Lippincott-Raven Publishers, 1997: 320-348.
2. Baumgartner TG. Magnesium. In: Baumgartner TG., ed. Clinical Guide to Parenteral Micronutrition, 3rd ed,
Fujisawa USA, Inc., 1997: 157-180.
3. Elin RJ. Magnesium metabolism in health and disease. Dis Mon 1988; 34 (4): 161-218.
4. McEvoy GK, ed. AHFS Drug Information® 98. Bethesda, MD: American Society of Health-System Pharmacists,
Inc., 1998: 1772-1775.
5. McLean RM. Magnesium and its therapeutic uses: a review. Am J Med 1994; 96: 63-76.
6. Olin BR, ed. Drug Facts and Comparisons. St. Louis, MO: Facts and Comparisons, Inc., 1998: 14-14a, 44-44b,
318.
7. Rude RK and Singer FR. Magnesium deficiency and excess. Ann Rev Med 1981; 32: 245-259.
8. Schultz NJ and Chitwood-Dagner KK. Body electrolyte homeostasis. In: Dipiro JT, Talbert RL, Yee GC, Matzke
GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach., 3rd ed, Stamford, CT: Appleton
& Lange, 1997: 1126-1130.
9. Whang R. Clinical disorders of magnesium metabolism. Comprehensive Therapy 1997; 23 (3): 168-173.
10. Whang R, Hampton EM, Whang DD. Magnesium homeostasis and clinical disorders of magnesium deficiency.
Ann Pharmacotherap 1994; 28: 220-226.
For further information on electrolyte product or nutritional replacement, please contact
FIRSTDOSE Pharmacy (#792-2179) or Nutrition Services (#792-4100). prepared 6/98 T.Seo, Pharm.D.
Table 3 - MAGNESIUM REPLACEMENT IN ADULTS
Indication
Dose
Mild Hypomagnesemia (1.3 - 1.5 mg/dl)
Magnesium Oxide 400 mg tablet
without Symptoms
1-2 tablets po QD-QID, as tolerated
Magnesium Gluconate 500 mg tablet
1-2 tablets po QD-QID, as tolerated
Magnesium Chloride SR tablet
1-2 tablets po QD-BID, as tolerated
Moderate to Severe Hypomagnesemia (< 1.3
mg/dl or < 1.6 mg/dl with Symptoms)
Magnesium Sulfate
1-2 g IV, up to q6hrs as needed
Magnesium Sulfate
Usual 4-6 g IV/day
Not to exceed 12. 5 g in 12 hrs
Severe Hypomagnesemia (< 1.3 mg/dl) with
Lifethreatening Symptoms (e.g., arrhythmias)
Magnesium Sulfate 2 g IV push over 1 min
(diluted to 10 ml in NS); then 0.5 mEq/kg LBM
IV infusion over 5-6 hrs; then 0.5 mEq/kg
LBM IV infusion over 17-18 hrs; then (on days
2-5), 0.5 mEq/kg LBM/day divided in
maintenance IV fluids.
Keep 10 ml Calcium Gluconate or Calcium
Chloride 10% IV on hand when administering
magnesium as IV bolus. (LBM = lean body mass)
Empiric dosing recommendations are for adults with normal organ function and are not meant to replace clinical
judgment for individual patient care.
Oral dosing ranges may differ from manufacturers’ labeling for chronic magnesium supplementation.
Clinical Practice Points
• Serum magnesium levels may not reflect total body magnesium content since only about 1 - 2 %
of magnesium is distributed in extracellular fluid.
• Replacement over 3 to 5 days may be necessary to replete total magnesium stores.
• Maintenance doses may be necessary in patients with continued magnesium losses.
• Caution should be taken in patients with renal impairment. These patients may require lower
doses (e.g., 50 % of normal dose) and more frequent monitoring.
• Oral magnesium product intake may be limited by diarrhea.
• Magnesium-Aluminum combination antacid products (e.g., Maalox®; Mylanta®) are generally
not recommended for oral magnesium replacement due to Al+3 content (which may accumulate in
renal impairment and may bind phosphate, with potential to promote additional magnesium
loss).
• For more rapid replacement than provided by oral administration, use parenteral route.
• Do not exceed intravenous infusion rate of 150 mg/min MgSO4 (rapid intravenous bolus may
cause flushing, sweating, or sensation of warmth).
• Dilute intravenous solutions to concentrations < 200 mg/ml (20%) MgSO4 prior to intravenous
administration to minimize risk of pain and venosclerosis (e.g., IVPB 2-4 g MgSO4/50-100 ml
NS or D5W).
• Intramuscular (IM) administration of MgSO4 should be reserved for situations in which
peripheral venous access is not readily obtainable since this route of administration may be
painful, often requires multiple punctures, and offers no therapeutic advantage over intravenous
administration.
3 Phosphorus Replacement in Adults (d07_2.frm)
The normal laboratory range for phosphorus is 2.5 - 4.5 mg/dl. For mild to moderate
hypophosphatemia (1 - 2.4 mg/dl), oral agents may be used. Oral phosphate-containing agents
available or on The Medical University of South Carolina Formulary of Accepted Drugs include:
Table I - PHOSPHATE-CONTAINING ORAL PRODUCTS
Product Name
Phosphorus Content
Sodium Phosphate Oral Solution 18 g with
Sodium Bisphosphate 48 g /100 ml
(Fleet Phospho-Soda®) 90 ml
4.15 mMol /ml
110 mg (4. 8 mEq) Na /ml
Sodium Phosphate Enema 6 g with Sodium
Bisphosphate 16 g /100 ml
(Fleet Enema®) 133 ml
1.38 mMol /ml
37 mg (1. 6 mEq) Na /ml
164 mg (7. 1 mEq) Na &
Potassium and Sodium Phosphate Powder
8
mMol
7.
1 mEq K per packet
(Neutra-Phos®) Packet
Potassium Phosphate Powder
(Neutra-Phos K®) Packet
8 mMol
14. 25 mEq K per packet
1 mMol Phosphate = 31 mg Elemental Phosphorus
For severe hypophosphatemia (< 1 mg/dl ,< 2 mg/dl if TPN is to be started, or < 2.5 mg/dl with
symptoms), parenteral phosphate replacement is generally indicated. Injectable phosphate is
available as potassium phosphate (4.4 mEq K /3 mMol phosphate) and sodium phosphate (4 mEq
Na /mMol phosphate).
Table 2 - PHOSPHATE-CONTAINING INTRAVENOUS PRODUCTS
Product Name
Potassium Phosphate
Sodium Phosphate
Phosphorus Content
15 mMol phosphate and 22 mEq K /5 ml
15 mMol phosphate and 20 mEq Na /5 ml
References
1. Brooks MJ and Melnick G. The refeeding syndrome: an approach to understanding its complications and
preventing its occurrence. Pharmacotherapy 1995;15 (6):713-726.
2.
Kingston M and Badawi A. Treatment of severe hypophosphatemia. Crit Care Med 1985;13:16-18.
3. Knoechel JP. The pathophysiology and clinical characteristics of severe hypophosphatemia. Arch Intern Med
1977; 137:203-220.
4. Lentz RD, Brown DM, Kjellstrand CM. Treatment of severe hypophosphatemia. Ann Intern Med 1978; 89: 941944.
5.
Lloyd CW and Johnson CE. Management of hypophosphatemia. Clin Pharm 1988;7:123-128.
6. Olin BR, ed. Drug Facts and Comparisons. St. Louis, MO: Facts and Comparisons, Inc., 1998: 12-12a,48-48a.
7. Perreault MM, Ostrop NJ, Tierney MG. Efficacy and safety of intravenous phosphate replacement in critically ill
patients. Ann Pharmacother 1997;31:683-688.
8. Popovtzer MM, Knochel JP, Kumar R. Disorders of calcium, phosphorus, vitamin D, and parathyroid hormone
activity. In: Schrier RW, ed. Renal and electrolyte disorders, 5th ed, Philadelphia: Lippincott-Raven Publishers,
1997: 241-319.
9. Rosen GH, Boullata JI, O’Rangers EA, et al. Intravenous phosphate repletion regimen for critically ill patients
with moderate hypophosphatemia. Crit Care Med 1995;23:1204-1210.
For further information on electrolyte product or nutritional replacement, please contact
FIRSTDOSE Pharmacy (#792-2179) or Nutrition Services (#792-4100). prepared 6/98 T.Seo, Pharm.D.
Table 3 - PHOSPHATE REPLACEMENT IN ADULTS*
Indication
Dose
Mild to moderate hypophosphatemia (1 - 2.4
K Phosphate or Na Phosphate
mg/dl) without symptoms
0.16 mMol phosphate/ kg IV over 6 hours
Neutra-Phos® or Neutra-Phos K®
1-2 packets po BID-QID, as tolerated
Dilute each packet in 75 ml water
Fleet Phospho-Soda®
5-15 ml po BID-TID, as tolerated
Dilute each dose in 120 ml water
Severe Hypophosphatemia (< 1 mg/dl, <2
mg/dl if TPN is to be started, or < 2.5 mg/dl
with symptoms)
Maximum phosphate dose
K Phosphate or Na Phosphate
Usual 0.2 - 0.24 mMol phosphate/kg IV over 6
hours
0.24 mMol phosphate/ kg over 6 hours
Usually not > than 45 mMol phosphate/24 hrs
Normal daily dose (after phosphorus level
returns to normal)
0.14 - 0.4 mMol phosphate/kg over 24 hours
Includes dietary intake of phosphorus
Empiric dosing recommendations are for adults with normal organ function and are not meant to replace clinical
judgment for individual patient care.
Oral dosing ranges may differ from manufacturers’ labeling for phosphorus supplementation.
Use ideal body weight (IBW) for dosing if total body weight is > than 20% over IBW.
*Note: Replacement dose is in addition to routine daily dose of 0.14 - 0.4 mMol phosphorus/kg/day
Clinical Practice Points
• It may be difficult to assess total body phosphorus deficit since < 1 % of phosphorus is
distributed in extracellular fluid and distribution may be affected by patient’s pH, blood glucose
concentration, and insulin availability.
• Caution should be taken in patients with renal impairment. These patients may require lower
doses and more frequent monitoring.
• Caution in patients with low serum calcium levels, as phosphorus replacement products may
promote hypocalcemia.
• Caution in patients with elevated serum calcium levels. Calcium-phosphorus solubility products
> 60 - 70 mg2/dl2 may produce calcium-phosphate soft tissue depositions.
•
Oral phosphorus product intake may be limited by diarrhea.
• Fleet Enema® may be given orally for phosphorus replacement.
•
Cow’s milk contains approximately 0.029 mMol Phosphorus per ml.
• Note K or Na content in phosphorus replacement products.
• Commercial injections are mixtures of monobasic and dibasic salt forms. To avoid confusion,
order and dispense in terms of mMol of phosphorus.
• No greater than 30 mMol K Phosphate/dosing unit for ICUs/8W or 15 mMol K
Phosphate/dosing unit for all other floors will be dispensed (per MUSC intravenous potassium
policy) (e.g., 15-30 mMol K Phosphate /250-500 ml NS or D5W).
• A minimum of 4 to 6 hours infusion is required for parenteral phosphate. Risks of rapid IV
infusion include hypocalcemia, hypotension, muscular irritability, calcium deposits, renal
function deterioration, and hyperkalemia (from K content in K phosphate).
3 Potassium Replacement in Adults (d07_3.frm)
The normal laboratory range for potassium is 3.6 - 5 mMol/L. For mild to moderate
hypokalemia (2.5 - 3.5 mMol/L)*, oral agents may be used. Oral potassium-containing agents
available or on The Medical University of South Carolina Formulary of Accepted Drugs include:
Table 1 - POTASSIUM-CONTAINING ORAL PRODUCTS
Product Name
Elemental Potassium Content
Potassium Chloride Controlled Release Tablet
(Ten-K®)
10 mEq
(750 mg potassium chloride)
(K-Dur 20 mEq®)
20 mEq
(1500 mg potassium chloride)
Potassium Chloride Powder
(K-Lor 20 mEq®)
20 mEq
(1500 mg potassium chloride)
Potassium Chloride Liquid 10%
1.333 mEq /ml
(Available also as unit dose cups: 20 mEq/15 ml;
30 mEq/22.5 ml; 40 mEq/30 ml)
Potassium Bicarbonate Effervescent Tablet
(K-Lyte®)
25 mEq
(with 2100 mg citric acid)
Potassium chloride 13.4 mEq/g salt; Potassium bicarbonate 10 mEq/g salt; Potassium citrate 9.8 mEq/g salt
# mMol/L serum potassium = # mEq/L serum potassium
For severe hypokalemia (< 2.5 mMol/L or < 3.6 mMol/L with symptoms),* parenteral potassium
replacement is generally indicated.
Table 2 - POTASSIUM-CONTAINING INTRAVENOUS PRODUCTS
Product Name
Potassium Chloride
Potassium Acetate
*Breakpoints arbitrarily assigned.
Elemental Potassium Content
2 mEq /ml
2 mEq /ml; 4 mEq /ml
Use clinical judgment in interpretation for patient specific care.
References
1. Bear RA and Neil GA. A clinical approach to common electrolyte problems: 2. potassium imbalances. Can Med
Assoc J 1983;129:28-31.
2. Kruse JA and Carlson RW. Rapid correction of hypokalemia using concentrated intravenous potassium chloride
infusions. Arch Intern Med 1990;150:613-617.
3. Mandal AK. Hypokalemia and hyperkalemia. Med Clin N Amer 1997;81(3):611-639.
4. McEvoy GK, ed. AHFS Drug Information® 98. Bethesda, MD: American Society of Health-System Pharmacists,
Inc., 1998:2140-2145.
5. Olin BR, ed. Drug Facts and Comparisons. St. Louis, MO: Facts and Comparisons, Inc., 1998:15-16c, 42-42c,
171c.
6. Saggar-Malik AK and Cappuccio FP. Potassium supplements and potassium-sparing diuretics: a review and guide
to appropriate use. Drugs 1993;46(6):986-1008.
7. Schultz NJ and Chitwood-Dagner KK. Body electrolyte homeostasis. In: Dipiro JT, Talbert RL, Yee GC, Matzke
GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach., 3rd ed, Stamford, CT: Appleton
& Lange, 1997:1113-1120.
8. Stanaszek WF and Romankiewicz JA. Current approaches to management of potassium deficiency. DICP
1985;19:176-185.
9. Whang R, Whang DD, Ryan MP. Refractory potassium repletion: a consequence of magnesium deficiency. Arch
Intern Med 1992;152:40-45.
10.
Zull DN. Disorders of potassium metabolism. Emer Med Clin N Amer 1989;7(4):771-793.
For further information on electrolyte product or nutritional replacement, please contact
FIRSTDOSE Pharmacy (#792-2179) or Nutrition Services (#792-4100). prepared 6/98 T.Seo, Pharm.D.
Table 3 - POTASSIUM REPLACEMENT IN ADULTS
Indication
Dose
ORAL REPLACEMENT*
Potassium Chloride
Serum potassium 2.5 - 3.5 mMol/L without
Usual 20-40 mEq po BID-QID, as tolerated
Symptoms
Mix each powder with at least 120 ml of cold
water or juice
Dilute KCl 10% liquid in cold water or juice to
improve palatability
K-Lyte® Effervescent Tablet
Usual 25 mEq po BID-TID, as tolerated
Dissolve each tablet in 90-120 ml of cold water
INTRAVENOUS REPLACEMENT**
Serum potassium > 2.5 mMol/L
KCl IV infusion, up to 200 mEq/day in divided
doses Refer to MUSC IV potassium policy for
maximum concentrations and infusion rates
Serum potassium < 2.5 mMol/L
KCl IV infusion, up to 400 mEq/day in divided
doses Refer to MUSC IV potassium policy for
maximum concentrations and infusion rates
Empiric dosing recommendations are for adults with normal organ function and are not meant to replace clinical
judgment for individual patient care.
*Note: In mild, asymptomatic cases (serum K > 3 mMol/L), increase in dietary K may be sufficient.
Oral dosing ranges may differ from manufacturers’ labeling for chronic potassium supplementation.
Usual prophylactic potassium doses are 20 - 30 mEq/day, divided into 2 - 3 doses as tolerated.
**The patient’s response, as determined by measurement of serum potassium concentration and ECG monitoring
following the initial 40 - 60 mEq infused, should indicate the subsequent infusion rate required.
Clinical Practice Points
• Serum potassium levels may not reflect total body potassium content since only about 2% of
potassium is distributed in extracellular fluid.
• Factors which promote 8 cellular uptake of K include: alkalosis, insulin, glucose, #-adrenergic
agonists, and aldosterone. Acidosis and #-adrenergic antagonists impair cellular uptake.
• During K depletion, serum K initially 9 by .1 mMol/L for each 100-200 mEq total body stores
lost; however, serum K falls more slowly after it reaches .2 mMol/L.
•
Replacement over several days may be necessary to replete total potassium losses.
• In hypomagnesmic states, potassium wasting may occur. Serum magnesium levels and
replacement may be necessary to address refractory hypokalemia.
• KCl is usually the salt of choice in potassium replacement, since the Cl- ion is required to correct
hypochloremia which frequently accompanies potassium deficiency.
• Alkalinizing salts of potassium (e.g., acetate, bicarbonate) are preferred in instances where
metabolic acidosis exists concurrently with potassium depletion.
• Potassium prophylaxis may be indicated to prevent hypokalemia in patients who would be at
particular risk if hypokalemia were to develop (e.g., patients on digoxin with cardiac
arrhythmias; hepatic cirrhosis with ascites; aldosterone excess with normal renal function;
potassium-losing nephropathy; chronic diarrhea conditions).
• Factors which may predispose to overcompensation with resultant hyperkalemia incl: 9 renal
function, diabetes mellitus, acidosis, and potassium-sparing medications (e.g., K-sparing
diuretics, ACE Inhibitors, Angiotensin II Receptor blockers).
•
•
Note: salt substitute products (e.g., Adolph’s®, Morton®, Nu-Salt®) contain a significant
amount of potassium (e.g., 56 - 68 mEq /5 g product).
Refer to phosphorus replacement guidelines for K Phosphate product information.