This information is intended for use by health professionals
Sterile Potassium Acid Phosphate Solution.
Potassium Acid Phosphate 13.6% w/v.
Sterile Aqueous Solution - Injection.
As a source of potassium ions and phosphate ions in electrolyte replacement therapy.
The normal concentration of serum inorganic phosphate is 3 to 4.5mg (0.03 to 0.045mmol) per 100ml in adults and 4 to 7 mg (0.04 to 0.07mmol) per 100ml in children.
Before administration, the concentrated phosphate injection must be diluted and thoroughly mixed with a larger volume of fluid.
The dose and rate of administration must be individualised.
When used as an electrolyte replenisher, a dose of the equivalent of 10 to 15mmol (310mg to 465mg) of phosphorus a day is usually sufficient to maintain normal serum phosphate, although larger amounts may be required in hypermetabolic states.
The solution should be infused slowly to avoid phosphate intoxication.
Usual adult and adolescent dose
As an electrolyte replenisher
The equivalent of 10mmol (310mg) of phosphorus a day by intravenous infusion
Usual Paediatric use
As an electrolyte replenisher
The equivalent of 1.5 to 2 mmol (46.5 to 62mg) of phosphorus a day by intravenous infusion.
Renal function impairment severe - less than 30% of normal
Risk - Benefit should be considered when the following medical problems exist
(reasons given when appropriate):
Conditions in which high phosphate concentrations may be encountered, such as
Chronic Renal Disease.
Conditions in which low calcium concentrations may be encountered, such as:
Chronic Renal disease.
Sensitivity to Potassium or Phosphates.
Cardiac disease, particularly in digitalised patients.
Conditions in which high potassium concentrations may be encountered, such as:
Severe adrenal insufficiency - Addison's disease
Severe renal insufficiency.
Extensive tissue breakdown, such as severe burns.
The product must be diluted before use.
Electrocardiogram (may be required at regular intervals during intravenous therapy)
Interactions with other medications include Captopril, Potassium - Sparing Diuretics, Enalapril, Lisinopril, Adrenocorticoids, Glucocorticoids (especially those with significant mineralocorticoid activity), Mineralocorticoids, Corticotropin (ACTH), Anabolic Steroids or Androgens.
Interaction with potassium containing medications (concurrent use with potassium phosphate may result in hyperkalaemia; patient should have serum potassium concentration determinations at periodic intervals).
Interaction with Digitalis Glycosides
Use of potassium phosphate injection in digitalised patients with severe or complete heart block is not recommended because of possible hyperkalaemia.
Interaction with Diuretics or Thiazides
Concurrent use with phosphate may cause or worsen renal damage.
Interaction with Mexiletine
May lead to marked acidification of urine by monobasic potassium phosphate and potassium and sodium phosphates combination may accelerate excretion of Mexiletine.
Interaction with Quinidine
Concurrent use with potassium phosphate usually enhances effects of the Quinidine.
Interaction with Salicylates
Concurrent use with potassium and sodium phosphates combination or monobasic potassium phosphate may increase plasma concentrations of salicylates since salicylate excretion is decreased in acidified urine; addition of these phosphates to patients stabilised on a salicylate may lead to toxic salicylate concentrations.
There has been no adequate and well controlled studies carried out in this area in either humans or animals.
It is not known if phosphates are excreted in breast milk. However problems in nursing infants have not been documented.
Undesirable effects include:
Fluid retention (swelling of feet or lower legs and weight gain).
Hyperkalemia (confusion, tiredness or weakness, irregular or slow heartbeat, numbness or tingling around lips, hands or feet, unexplained anxiety, weakness or heaviness of legs, shortness of breath or troubled breathing).
Hypernatremia (confusion, tiredness or weakness, convulsions, decrease in amount of urine or in frequency of urination, fast heartbeat, headache or dizziness, increased thirst).
Hypocalcemic tetany (muscle cramps, numbness, tingling, pain or weakness in hands or feet, shortness of breath or troubled breathing).
May result in hyperkalaemia and hyperphosphataemia.
Recommended treatment consists of the following:-
Withholding administration of phosphates
Correcting deficient serum electrolyte concentrations (such as that of calcium)
Potassium is the principle cation in intracellular fluid. It is involved with carbohydrate metabolism, glycogen storage and protein synthesis.
It is involved with transmembrane potential and profound effects on muscle.
Phosphorus has many important biochemical functions in the body and is involved in many significant metabolic and enzyme reactions in almost all organs and tissues.
The normal levels of potassium in intracellular fluid and plasma are 160mmol/l and 3.5 - 5.0mmol/l respectively.
The normal level of phosphate in plasma is 0.8 - 1.5mmol/l.
Disodium Edetate BP
Water for Injection BP
A precipitate may form when phosphates are added to a solution containing calcium or magnesium.
Product is filled into clear colourless 10ml ampoules of Ph.Eur. type I glass.
Packed into cartons of 10 ampoules.
Macarthys Laboratories Limited
T/A Martindale Pharmaceuticals
19th January 1984