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.

Elemental Magnesium Usual

FORMULARY AGENTS mg mEq_____ Dose_________

MgOxide 400 mg tablets 240 20 1-2 tablets daily
MgHydroxide (MOM®) 10 ml 360 30 1-2 times a day
MgHydroxide (Maalox®) 10 ml 180 15 1-2 times a day

ADVERSE EFFECTS: Diarrhea (may be reduced by dividing daily doses)

For Mg levels < 1.2 mg/L or symptomatic or patient unable to take oral

Magnesium sulfate equivalencies: 1 gm MgSO4 =100 mg Mg= 8 mEq Mg

SYMPTOMATIC/ASYMPTOMATIC

WEIGHT OR Mg < 1.2 mg/dl AND Mg > 1.2 mg/dl < 50 kg 2-3 gm Mg Sulfate 1-2 gm Mg Sulfate >50 kg 3-4 gm Mg Sulfate 2-3 gm Mg Sulfate

Additional doses of 1-2 gms/day of Mg sulfate may be required for several days if the patient has not previously been receiving magnesium.

Renal insufficiency (CLcr < 20ml/min) may require lower doses of magnesium. Caution should be used when replacing magnesium in any patient with renal insufficiency.

MAXIMUM CONCENTRATION: 1 gm in 5 ml D5W or NS

MAXIMUM INFUSION RATE: 1 gm over 7 minutes

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

Repeat magnesium levels can be drawn the next day or sooner, if necessary.

For Phosphorus > 1 mg/dl (>0.3 mmol/L), oral therapy may be used:

FORMULARY Phosphorus Sodium Potassium

AGENTS mmol /mEq

Neutra-Phos® 8 7 7 per capsule/powder packet*

Neutra-Phos K® 8 0 14 per capsule/powder packet*

Skim milk per 8 oz 4 3 5

USUAL DOSE: 1-2 powder packets* or capsules* (8-16 mmol) of Neutra-Phos or Neutra-Phos K po/ng tid.

*Each Neutra-phos capsule/packet must be opened and diluted with 75 ml of water before administration.

8 oz skim milk (4 mmol of Phos) tid

ADVERSE EFFECT: Diarrhea (will decrease Mg absorption)

NOTE: Magnesium, calcium and aluminum containing antacids may bind phosphorus and prevent its absorption, so should be avoided in patients with low phosphate levels.

For Phosphorus < 1 mg/dl (< 0.3mmol/L), IV phosphorus should be given.

FORMULARY AGENTS Phosphorus Sodium Potassium

Potassium phosphate 3 mmol/ml 0 4.4 mEq/ml

Sodium phosphate 3 mmol/ml 4 mEq/ml 0

USUAL DOSE: For acute decreases in PO4: 0.25 mmol/kg IBW*

For chronic depletion of PO4: 0.5 mmol/kg IBW*

Renal insufficiency (CLcr <20ml/min): reduce dose by 50%

As a guideline, the phosphorus level will increase by an average of 1.2 mg/dl with a dose of 0.25mmol/kg

*IBW: Men = 50 + 2.3 (inches over 5 feet)
Women = 46 + 2.3 (inches over 5 feet)

Recommended concentrations and rate of administration:

KPhos 6 mmol / 100 ml NS or D5W over 4 hours peripherally or centrally not to exceed 15 mmol per minibag*

NaPhos 10 mmol / 100 ml NS or D5W over 4 hours peripherally or centrally.

Maximum concentrations and rate of administration:

Use of these concentrations and rates requires continuous monitoring and is restricted to those areas which can provide that level of care except in emergent situations.

This method of administration is NOT recommended if:

total calcium is < 7.5 mg/dL or > 11 mg/dL (corrected for albumin**) phosphorus is > 2 mg/dL OR significant renal dysfunction (Clcr < 10 ml/min)

KPhos 15 mmol / 100 ml NS or D5W over 2 hours centrally.*

NaPhos 15 mmol / 100 ml NS or D5W over 2 hours centrally.

*Although 15mmol of KPhos provides 22 meq of potassium which exceeds the recommended dose of potassium per minibag (20 meq), the maximum infusion rate of 2 hours complies with current potassium administration guidelines (i.e., 20meq/100ml NS or D5W over minimum 1 hour centrally).

**Correction for low albumin: For every 1mg/dL of albumin below 4 mg/dL, add 0.8 mg/dL to total calcium:

Ca corrected = [(4- albumin) x 0.8] + Ca measured

Phosphorus levels should be drawn at the end of the infusion and should always be drawn prior to any additional doses administered.

Note: Phosphorus has historically been administered over 4 to 6 hours due to the potential risk associated with high doses and rapid administration (i.e., hypocalcemia, hypotension, metastatic calcification, renal failure). However, most of this data comes from cases of hypercalcemia treated with large doses of intravenous phosphates in which phosphorus levels were typically normal. More aggressive electrolyte replacement is not considered as risky.

A. Normal serum potassium value is 4.0 - 5.0 mmol/L

B. Magnesium levels should be monitored and replacement given if necessary since potassium repletion is ineffective in the presence of hypomagnesemia.

A. Rapid infusion of KCl may cause cardiac arrest.

B. Avoid extravasation. Thrombophlebitis may result and is related to the rate, concentration and size of vein.

C. Signs and symptoms of hypokalemia (K+ < 3.5 mmol/L)

1. muscle weakness 5. hypotension

2. anorexia 6. weak pulse

3. vomiting 7. ECG changes: flattened ST segment, T wave

4. heart block, dysrhythmias inversion and U wave elevation

5. hypotension

6. weak pulse

7. ECG changes: flattened ST segment, T wave

D. Risk Factors for developing hypokalemia

1. diarrhea, vomiting

2. amphotericin B

3. diuretics

4. metabolic alkalosis

5. insulin

6. beta2 agonists (e.g., terbutaline)

E. Signs and symptoms of hyperkalemia (K+ > 5.0 mmol/L)

1. confusion 4. flaccid paralysis

2. listlessness, irritability 5. bradycardia

3. paresthesias of extremities 6. peaked T-waves on ECG, dysrhythmias

4. flaccid paralysis

5. bradycardia

6. ECG changes peaked T-waves on ECG, dysrhythmias

F. Risk Factors for developing hyperkalemia

1. renal impairment

2. use of ACE Inhibitors (captopril, enalapril, lisinopril, etc.)

3. use of potassium sparing diuretics (spironolactone, amiloride, etc.)

4. use of high dose TMP/SMX for PCP in HIV infected patients

G. Patients on digoxin are more likely to develop digoxin toxicity if K+ is low.

H. If burning or stinging sensation occurs while KCl is being given via peripheral line, the discomfort may be reduced by the following methods:

1. decrease rate of infusion

2. reduce the concentration of KCl

I. Potassium chloride must never be administered by IV push or IM injection.

II. All potassium chloride infusions will be supplied by the Pharmacy Department. These infusions will be commercially prepared in minibags, or compounded by the Pharmacy. Potassium Chloride vials will not be stocked in any patient care areas. Any exceptions will need to be petitioned to the P & T Committee. In pediatric or neonatal patients, all infusions will be administered via an infusion pump and burette, or by a syringe pump.

III. All IV maintenance infusions with KCl at a concentration greater than 40 mEq/L must be administered via an infusion pump.

IV. Peripheral administration

A. In adults, the maximum concentration via peripheral line is 10 mEq/100 ml.

B. In adults, the maximum amount of KCl available in each IV minibag is 20 mEq. In nenoates or pediatrics only two hours worth of fluid volume will be added to the burette at anytime. Only one hour worth of fluid should be in a syringe pump.

C. The maximum infusion rate via peripheral line is 10 mEq per hour. In neonates and pediatrics, the maximum infusion rate via peripheral line is 0.5 - 1 meq/kg/hour.

V. Central administration

A. In adults, the preferred concentration via central line is 20 mEq/100 ml. The maximum concentration for fluid restricted patients is 20 mEq/50 ml.

B. In adults, the maximum amount of KCl available in each IV minibag is 20 mEq. In neonates or pediatrics only two hours worth of fluid volume will be added to the burette at anytime. Only one hour worth of fluid should be in a syringe pump.

C. The maximum infusion rate via central line is 20 mEq/hr. In neonates and pediatrics, the maximum infusion rate via central line is 1 meq/kg/hour.

VI. In adults, potassium levels must be checked after a total of 60 mEq has been administered. Potassium levels must be checked no sooner than 60 minutes after a given IV dose. In neonates and pediatrics, potassium levels must be checked after a total of 1 meq/kg has been administered.

A. Oral potassium chloride replacement should be considered in asymptomatic patients with serum potassium levels < 3.8 mEq/L.

B. Adult doses from 40-100 mEq/day may be required for potassium repletion given in 2 - 4 divided doses per day. In the neonate and pediatric patient, 1-3 meq/kg/day may be required for potassium repletion given in 2 - 4 divided doses per day.

C. 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. In the neonate, start with 0.5 - 1 meq/kg/day and titrate to desired level with the maximum dose of 3 meq/kg within a 6 hour period.

D. 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. For the neonate, a maximum total dose (IV + PO) is 3 meq/kg within a 6 hour period.

E. Do not use sustained release potassium products, (e.g., KDur™) when an immediate response is desired. The potassium chloride powder, dissolved in water, or potassium chloride solution, should be used for a quicker response.

F. Potassium levels must be checked after each replacement dose. If using immediate release preparations (KCl powder), 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.