Slow K

1. For the treatment of patients with hypokalemia with or without metabolic alkalosis, in digitalis intoxication, and in patients with hypokalemic familial periodic paralysis. If hypokalemia is the result of diuretic therapy, consideration should be given to the use of a lower dose of diuretic, which may be sufficient without leading to hypokalemia.
2. For the prevention of hypokalemia in patients who would be at particular risk if hypokalemia were to develop, e.g., digitalized patients or patients with significant cardiac arrhythmias.

The use of potassium salts in patients receiving diuretics for uncomplicated essential hypertension is often unnecessary when such patients have a normal dietary pattern, and when low doses of the diuretic are used. Serum potassium should be checked periodically, however, and, if hypokalemia occurs, dietary supplementation with potassium-containing foods may be adequate to control milder cases. In more severe cases, and if dose adjustment of the diuretic is ineffective or unwarranted, supplementation with potassium salts may be indicated.

Slow K Concentrate 15% is used as a source of the potassium cation for the treatment or prevention of potassium depletion in patients for whom dietary measures or oral medication are inadequate. Potassium salts may also be used cautiously in those taking digoxin where potassium depletion may cause arrhythmias. Slow K Concentrate 15% must be administered by slow IV, as a dilute solution.

The usual dietary potassium intake by the average adult is 50 to 100 mEq per day. Potassium depletion sufficient to cause hypokalemia usually requires the loss of 200 or more mEq of potassium from the total body store.

Dosage must be adjusted to the individual needs of each patient. The dose for the prevention of hypokalemia is typically in the range of 20 mEq per day. Doses of 40-100 mEq per day or more are used for the treatment of potassium depletion. Dosage should be divided if more than 20 mEq per day is given such that no more than 20 mEq is given in a single dose. The dose should be taken after a meal.

Slow K (potassium chloride) 20 mEq powder provides 20 mEq of potassium chloride.

Each 20 mEq (one Slow K (potassium chloride) 20 mEq packet) of potassium should be dissolved in at least 4 oz (approximately 1/2 glassful) cold water or juice. This preparation, like other potassium supplements, must be properly diluted to avoid the possibility of gastrointestinal irritation.

Adults (including elderly) and Children:

Slow K Concentrate 15% must be diluted by adding to a large volume intravenous fluid before use. For example, 10mls diluted with not less than 500mls 0.9% Sodium Chloride Intravenous Infusion BP, or other suitable diluent, and mixed well.

Dosage depends on the serum ionogram value and the acid-base state. A potassium deficiency is calculated according to the formula:

MMOL Potassium = KG BW x 0.2 x 2 x (4.5 - actual serum potassium (MMOL)).

(The extracellular volume is calculated from the body weight in KG x 0.2).

It is recommended not to exceed 2-3 MMOL potassium per kg body weight in 24 hours.

Potassium supplements are contraindicated in patients with hyperkalemia since a further increase in serum potassium concentration in such patients can produce cardiac arrest. Hyperkalemia may complicate any of the following conditions: chronic renal failure, systemic acidosis such as diabetic acidosis, acute dehydration, extensive tissue breakdown as in severe burns, adrenal insufficiency, or the administration of a potassium-sparing diuretic, e.g., spironolactone, triamterene, or amiloride (see OVERDOSAGE).

Slow K (potassium chloride) (potassium chloride for oral solution) is contraindicated in patients with known hypersensitivity to any ingredient in this product.

Hyperkalaemia, hyperchloraemia, impaired renal function with oliguria, anuria or azotaemia, Addison's disease, acute dehydration and heat cramps.

WARNINGS

Hyperkalemia

(see OVERDOSAGE)

In patients with impaired mechanisms for excreting potassium, the administration of potassium salts can produce hyperkalemia and cardiac arrest. This occurs most commonly in patients given potassium intravenously, but may also occur in patients given potassium orally. Potentially fatal hyperkalemia can develop rapidly and can be asymptomatic. The use of potassium salts in patients with chronic renal disease, or any other condition which impairs potassium excretion, requires particularly careful monitoring of the serum potassium concentration and appropriate dosage adjustment.

Interaction with Potassium-Sparing Diuretics

Hypokalemia should not be treated by the concomitant administration of potassium salts and a potassium-sparing diuretic, e.g., spironolactone, triamterene, or amiloride, since the simultaneous administration of these agents can produce severe hyperkalemia.

Interaction with Angiotensin Converting Enzyme Inhibitors

Angiotensin converting enzyme (ACE) inhibitors (e.g., captopril, enalapril) will produce some potassium retention by inhibiting aldosterone production. Potassium supplements should be given to patients receiving ACE inhibitors only with close monitoring.

Metabolic Acidosis

Hypokalemia in patients with metabolic acidosis should be treated with an alkalinizing potassium salt such as potassium bicarbonate, potassium citrate, potassium acetate or potassium gluconate.

PRECAUTIONS

General

The diagnosis of potassium depletion is ordinarily made by demonstrating hypokalemia in a patient with a clinical history suggesting some cause for potassium depletion. In interpreting the serum potassium level, the physician should bear in mind that acute alkalosis per se can produce hypokalemia in the absence of a deficit in total body potassium, while acute acidosis per se can increase the serum potassium concentration to within the normal range even in the presence of a reduced total body potassium. The treatment of potassium depletion, particularly in the presence of cardiac disease, renal disease, or acidosis, requires careful attention to acid-base balance and appropriate monitoring of serum electrolytes, the electrocardiogram, and the clinical status of the patient.

Laboratory Tests

When blood is drawn for analysis of plasma potassium it is important to recognize that artifactual elevations can occur after improper venipuncture technique or as a result of in vitro hemolysis of the sample.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenicity, mutagenicity and fertility studies in animals have not been performed. Potassium is a normal dietary constituent.

Pregnancy Category C

Animal reproduction studies have not been conducted with Slow K (potassium chloride) powder. It is unlikely that potassium supplementation that does not lead to hyperkalemia would have an adverse effect on the fetus or would affect reproductive capacity.

Nursing Mothers

The normal potassium ion content of human milk is about 13 mEq per liter. Since oral potassium becomes part of the body potassium pool, as long as body potassium is not excessive, the contribution of potassium chloride supplementation should have little or no effect on the level in human milk.

Pediatric Use

Safety and effectiveness in children have not been established.

Slow K Concentrate 15% must not be injected undiluted.

Plasma potassium concentration must be measured at regular intervals to avoid the development of hyperkalaemia, especially in patients with renal impairment.

ECG monitoring facilities should be available.

Initial potassium replacement therapy should not involve glucose infusions, because glucose may cause a further decrease in the plasma potassium concentration.

Potassium supplements should be administered with caution in patients with cardiac disease and in patients who are receiving potassium sparing diuretics or other medications which may increase plasma potassium levels.

One of the most severe adverse effects is hyperkalemia (see CONTRAINDICATIONS, WARNINGS, and OVERDOSAGE).

The most common adverse reactions to oral potassium salts are nausea, vomiting, flatulence, abdominal pain/discomfort, and diarrhea. These symptoms are due to irritation of the gastrointestinal tract and are best managed by diluting the preparation further, taking the dose with meals, or reducing the amount taken at one time.

Skin rash has been reported rarely.

Pain at the injection site and phlebitis may occur during IV administration of solutions containing 30 MMOL potassium or more per litre.

Hyperkalaemia is the most common and serious hazard of potassium therapy.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard.

The administration of oral potassium salts to persons with normal excretory mechanisms for potassium rarely causes serious hyperkalemia. However, if excretory mechanisms are impaired or intravenous administration is too rapid, potentially fatal hyperkalemia can result (see

Clinical signs and symptoms of potassium overdosage include: Paraesthesia of the extremities, listlessness, mental confusion, weakness or heaviness of the legs, flaccid paralysis, cold skin, grey pallor, peripheral vascular collapse, fall in blood pressure, cardiac arrhythmias and heart block. Extremely high plasma potassium concentrations (8-11 MMOL/litre) may cause death from cardiac depression, arrhythmias or arrest.

Cardiac arrhythmias or a serum concentration above 6.5 MMOL/litre, require immediate attention and may be treated by intravenous injection over 1 - 5 minutes of 10 - 20 ml of 10% Calcium Gluconate Injection B.P. with E.C.G. monitoring. Serum concentrations may be reduced by infusion of 300 - 500 mls per hour of 10% - 25% glucose solutions containing up to 10 units of insulin for each 20 g of glucose, or by the infusion of sodium bicarbonate solution.