7. HYPOMAGNESEMIA
• Irritability, confusion, arrhythmias, weakness,
nystagmus,seizures, coma, and death
• concomitant hypokalemia and hypocalcemia
Hypocalcemia
• Tetany, muscle spasms, lethargy, seizures
Chloride
• Tonicity Disturbence
8. • Working with physicians, pharmacists play an important role in
the determination of underlying causes of these disorders,
particularly when disorders are medication-related, and in
providing knowledge of the potential implications of individual
medications.
• Pharmacists also often evaluate and recommend treatment of
electrolyte disturbances.
• What are the standards for safe and effective administration in
Peripheral Vs Central line ?
the Recommended maximum concentrations and maximum
rates of infusion?
• Available Intravenous and oral forms?
9. • How to replace and maintain the electrolytes?
- REPLACEMENT DOSE, central venous catheter.
- MAINTANCE DOSE.
• Physician orders verification and calculations
millmoles (mmol) , milliequivalnts (mEq) or grams or
percentage.
• Proper Labeling .
• High risk Electrolytes? auxiliary labeling
Concentrated electrolytes shall not be part of routine floor stock.
• Administration :
- Do not give IV PUSH (except for magnesium and calcium).
- Mechanical infusion pump for all replacement electrolytes.
10.
11. • Renal function
• Salt form
• acid/base status
• Time of lab draw
• Route of administration
• Absorption issues
• Diarrhea, nausea/vomiting
13. Hypokalemia
Severity Serum K
concentration
(mEq/L)
Initial I.V. K
replacement dose
Mild/Moderate
2.5-3.4 20-40 mEq
Severe >2.5 40-80 mEq
• Every 1 mEq/L below 3.5 represents a 100-200 mEq deficit.
• One time dose of 40 mEq is not adequate replacement.
• Magnesium levels should be monitored and replacement given if necessary
since potassium repletion is ineffective in the presence of hypomagnesemia.
• Oral replacement if asymptomatic and K is < 3.8 mEq/L.
• Oral = IV K at same doses. Potassium chloride slow release tablet contains 8
mmol potassium per tablet. (Tablets should not be crushed or chewed).
• Liquid has unpleasant taste.
14. .
• Adult doses from 40-100 mEq/day may be required for potassium repletion given in 2
- 4 divided doses per day.
• In adults, start with 20-40 mEq/day and titrate to desired level. A 40 mEq dose may be
given every 2 hours for a maximum dose of 120 mEq within a 6 hour period.
• Oral potassium can be prescribed in conjunction with IV potassium.
• When oral potassium therapy is combined with parenteral supplementation for adults, a
maximum total dose (IV + PO) is 120 mEq within a 6 hour period.
• Do not use sustained release potassium products, when an immediate response is
desired. potassium chloride solution, should be used for a quicker response.
• Avoid dextrose vehicles - may stimulate insulin release and decrease K specially in
Initial replacement therapy.
• Potassium salts MUST NEVER be given IM or as an IV push.
15. • Potassium levels must be checked after each replacement dose. If
using immediate release preparations, a level should be checked no
sooner than 60 minutes.
If using a sustained release product, a level should be checked no
sooner than 3 hours.
Patients receiving maintenance doses of oral potassium do not require
levels after each dose.
16. • All IV maintenance infusions with KCl at a concentration greater than 40 mEq/L
must be administered via an infusion pump.
• Peripheral administration.
• Central administration.
• Cardiac Monitoring:
greater than 10 mmol/hour
SERUM less than or equal to 2.5 mmol/L.
DOSE exceeds 80 mmols
- Rapid infusion of KCl may cause cardiac arrest.
17. - Risk Factors for developing hypokalemia:
• Severe vomiting/diarrhea
• amphotericin B
• Chronic diuretics
• metabolic alkalosis
• insulin
• beta2 agonists (e.g., terbutaline)
• Decreased intake of K+
• Acid/base imbalance
• Trauma and stress
• Increased aldosterone
• Beware if diabetic
– Insulin pushes K+
into cells
– Ketoacidosis – H+
replaces K+
, which is lost in urine
• β – adrenergic drugs or epinephrine
18. • A single salbutamol nebulizer treatment may lower serum K by
0.2-0.4 mmol/L.
• A single dose of succinylcholine will increase serum K by 0.5-
1.0 mmol/L.
• Hyperkalaemia may occur with TMP/SMX (trimethoprim-
sulfamethoxazole) therapy and with the use of hypertonic
agents (e.g. D50, mannitol).
• A serum K of 3-4 mmol/L correlates with a 100-200 mmol K
deficit. At a serum K of 2-3 mmol/L, the deficit is 200-400 mmol.
• Serum potassium may be expected to increase by ˜ 0.25
mmol/L for each 20 mmol IV KCL infused.
• Hypokalemia :
• intracellular shift, including albuterol, insulin, theophylline, and
caffeine.
19. Hyperkalaemia:
- Risk Factors for developing hyperkalemia:
• Serum K+ > 5.5 mEq / L
• Check for renal disease
• Massive cellular trauma
• Insulin deficiency
• Addison’s disease
• Potassium sparing diuretics (spironolactone, amiloride, etc.)
• Decreased blood pH
• Exercise pushes K+ out of cells
• use of high dose TMP/SMX for PCP in HIV infected patients
- Hemodialysis
20. Management :
• 10% Calcium Gluconate or Calcium Chlorideas calcium will antagonize
the effects of potassium to rapidly stabilize cardiac muscle function
• Insulin (0.1U/kg/hr) and IV Glucose
• albuterol
• Metabolic alkalosis (if the patient is acidemic)
– 1 L H20 with 150meq of NaHCO3
• Lasix 1mg/kg (if renal function is normal)
• Sodium polystyrene sulfonate acts as a cation exchange resin,
binding to potassium in the gastrointestinal tract to facilitate
elimination.
• Renal replacement therapy
22. HYPOMAGNESEMIA
• thiazide and loop diuretics, amphotericin, cisplatin, cyclosporine, and digoxin.
• 1 g IV Mg = 8 mEq= 4 mmol
• Normal serum levels needed for potassium and calcium replacement (If
the magnesium concentration is low, it should be corrected, otherwise it will
be difficult to normalize potassium and calcium).
• Approximately 50% of the dose given is renally eliminated.
• Replace P.O. if patient can tolerate (diarrhea -rate limiting side effect ,may be
reduced by dividing daily doses).
Serum Mg
concentration
(mEq/L)
Oral Intravenous
1.0-1.5 (mild/moderate) Magnesium oxide
400 mg 1-2 tablets TID
8-32 mEq
<1.0 (severe) N/A 32-64 mEq
23. • An additional consideration is that magnesium levels drawn after
infusion may be falsely elevated due to magnesium’s slow
distribution into body tissues
• Takes 3 to 5 days for total repletion.
• Max IV rate = 1 g per hour.
• < 20% (200 mg/ml) concentration before administration.
• MAX. CONC. : 1 gm in 5 ml D5W or NS
• MAX. INFUSION RATE: 1 gm over 7 minutes
24. • For Mg levels > 1.2 mg/dl AND asymptomatic, oral* therapy may be
used:
• *Oral absorption is variable with 15-50 % of a dose being absorbed.
1-2 tablets daily
• Magnesium sulfate may be given IM, however it can be very painful.
Doses greater than 1 gm must be given in different injection sites.
• For symptomatic patients, bolus doses of IV magnesium are
required.
• For asymptomatic patients, adding magnesium to the patient's
maintenance IV fluids will allow for better retention of magnesium
• HYPERMAGNESEMIA
• ntravenous calcium (chloride or gluconate) to stabilize cardiac and
neuromuscular function.
• loop diuretics or renal replacement therapy
26. HYPOPHOSPHATEMIA
• Role in several important body functions
• Potassium Phosphate.
• Sodium Phosphate.
• Sodium Phosphate and Normal Saline.
• Recommended Total dose infused over 4-6 hrs to reduce risk of
(hypocalcemia and soft tissue calcification, hypotension, renal
failure)
• Oral Phosphateshould be used if asymptomatic/mild hypophosphatemia (can
cause diarrhea) (will decrease Mg absorption)
• Magnesium, calcium and aluminum containing antacids may bind phosphorus
and prevent its absorption.
PO4 Concentration (mg/dL) IV replacement dose
2.3-3.7 0.08-0.16 mmol/kg
1.5-2.2 0.16-0.32 mmol/kg
<1.5 0.32-0.64 mmol/kg
27. • Millimoles
• Maximum rate= 10 mmol/hr
- KPhos 15 mmol / 100 ml NS or D5W over 3 hours centrally.*
- NaPhos 15 mmol / 100 ml NS or D5W over 3 hours centrally.
Unless total calcium is < 7.5 mg/dL or > 11 mg/dL (corrected)
phosphorus is > 2 mg/dL OR significant renal dysfunction
(Clcr < 10 ml/min)
• IDEAL body weight (IBW) or adjusted weighs for obese patient.
• 4 hours after replacement completed.
• Renal insufficiency (CLcr <20ml/min): reduce dose by 50%
• Maximum is 15 mM of sodium phosphate in 100 ml dextrose 5%
in water
• As a guideline, the phosphorus level will increase by an average
of 1.2 mg/dl with a dose of 0.25mmol/kg
28. • Hyperphosphatemia
• phosphate binders such as calcium carbonate, calcium acetate,
and sevelamer orally with meals to reduce phosphorus
absorption from the gastrointestinal tract.
• renal replacement therapy
30. HYPOCALCEMIA
• NORMAL LEVELS: Total Calcium: 8.4-10.2 mg/dl (2.1-2.6 mmol/L)
• Highly protein bound so always calculate corrected calcium.
Corrected calcium = [(4-albumin) x 0.8] + serum calcium.
• Ionized calcium remains normal in low albumin states.
• Calcium chloride and Calcium gluconate
• Calcium chloride only used in severe situations typically codes
• Gram , mmol
Total Ca (mg/dL) Dosing Continuous IV dose
Mild/moderate
And asymptomatic
0.08-0.16 mmol/kg 4.56-9.12 mEq Ca
over 30-60 minutes
<7.5 (Severe)
Or symptomatic
3 g calcium gluconate
over 10 minutes
repeat PRN
13.6 mEq Ca over 10 min.
repeat PRN
31. – If the magnesium concentration is low, it should be corrected, otherwise it will
be difficult to normalize potassium and calcium
– MAXIMUM RECOMMENDED CONCENTRATIONS:
• Calcium gluconate: 1 gm in 50 ml D5W or NS.
• Calcium chloride*: 1 gm in 100 ml D5W or NS
– INFUSION RATE: Infuse over 30-60 minutes.
Rapid administration may cause bradycardia, hypotension and vasodilation.
– Administration via a central or deep vein is preferred. IM or SC?
– Phosphate and Calcium replacements, Determine Ca x PO4 product in mg/dl
before administering calcium.
If product is greater than 60 mg/dl, there is an increased risk of calcium
phosphate precipitation in the cornea, lung, kidney, cardiac conduction
system, and blood vessels.
32. • Usual maximum total daily dose is 15 g calcium gluconate.
• As a guideline, the total calcium will increase by 0.5 mg/dl for
every gram of calcium gluconate given intravenously.
• ORAL CALCIUM Absorption is variable and depends on
PTH, Vitamin D, and gastric pH.
• USUAL DOSE: 500- 2000 mg elemental calcium a day, in
divided doses (BID-QID)
– ADVERSE EFFECT: Constipation
• For each 5 units of packed RBCs transfused, administer 1-2
grams (1-2 amps) of calcium gluconate.
33. Sodium
• May reflect increased, decreased or normal total body sodium
• Sodium is the major cation that determines serum osmolality,
• Must assess osmolality to treat Various causes (SIADH, CHF, Ascites)
• Normal serum sodium levels are 136 -145 mEq / L.
• Max rate of increase in serum sodium is 8-12 mEq/L in 24 hrs
• Assess underlying cause and treat first.
• acute onset hyponatremia is more likely to be symptomatic and
• can be more rapidly corrected compared to chronic hyponatremia,
which is usually not associated with as severe of symptoms and should
be corrected slowly.
** All replacement doses reflect dosing for patients with
Normal renal function**
34. 34
Treatment of
Hyponatremia
• Correct serum Na by 1mEq/L/hr
• Check serum Na q4hr
• Use 3% saline in severe hyponatremia
• Central venous catheter, venous irritation and pain at the
injection site.
• Administer osmotic diuretic (Mannitol) to excrete the water
rather than the sodium
• Goal is serum Na 130
• Avoid too rapid correction
35. • Hypernatremia: Plasma Na+ > 145 mEq / L
– Excess Na intake (hypertonic IV solution)
– Excess Na retention (oversecretion of aldosterone)
– Loss of pure water
• Long term sweating with chronic fever
• Respiratory infection → water vapor loss
• Diabetes (mellitus or insipidus) – polyuria
– Insufficient intake of water (hypodipsia)
Management:
• 45% NSS. If caused by both Na and fluid loss, will administer
NaCL. If inadequate renal excretion of sodium, will administer
diuretics.