Source: Health Products Regulatory Authority (IE) Revision Year: 2020 Publisher: Essential Pharma (M) Limited, Vision Exchange Building, Triq it-Territorjals, Zone 1, Central Business District, Birkirkara, CBD 1070, Malta
Pharmacotherapeutic group: Potassium supplement
ATC code: A12BA01
Potassium, as the most abundant intracellular cation, plays an essential role in several important physiological functions, including transmission of nerve impulses, contraction of cardiac, skeletal, and smooth-muscle tissues, and maintenance of normal renal function. It also aids in the regulation of osmotic pressure and the acid-based balance. Concentrations of K+ range in intracellular fluid from 130 to 150 up to 160 mmol/L and in plasma from 3.5 to 5 mmol/L.
Although there is no uniform correlation between plasma concentrations of potassium and total body stores, clinical signs of K+ deficiency are usually observed whenever the plasma potassium concentration falls below 3.5 mmol/L (hypokalemia). These signs include: impaired neuromuscular function, which may vary from minimal weakness to frank paralysis; intestinal dilatation and ileus; and, more frequently, abnormalities myocardial function with disturbed ECG patterns characterized by a prolonged PR interval, an exaggerated U wave, a broad and flat T wave, and a depressed ST segment.
Hypokalemia can be prevented and/or corrected by giving supplementary potassium. Apart from increasing dietary intake of potassium-rich foods, which may not always be practicable, a suitable alternative is to administer Slow-K. In view of the frequency with which deficits of K+ and CL- coexist, potassium chloride is the preferred salt for most of the clinical conditions associated with hypokalemia.
Following a single dose of Slow K, potassium chloride is released over a period of approximately 4 hours. Renal excretion of potassium chloride following ingestion of Slow K occurs 30-60 minutes later than when the same dose is given in the form of a solution.
In the presence of a normal potassium balance 90% of the potassium supplied by Slow K is excreted renally within 8 hours and more than 98% by 24 hours.
The Slow-K tablet matrix is not absorbed and is excreted in the faeces; in some instances, it may be noticeable in the stool. The release of matrix in the faeces does not relate to any loss of efficacy of the drug.
No pharmacokinetics studies of potassium chloride are reported in elderly population. However, these patients are more likely to develop hyperkalemia due to physiological changes, and reduced renal function.
No pharmacokinetics studies of potassium chloride are reported in the pediatric population.
No pharmacokinetics studies of potassium chloride are reported in patients with hepatic impairment.
Potassium is almost completely excreted via urine and its excretion rate highly correlates with the glomerular filtration rate. Considering the possibility of hyperkalemia in these patients and severity of outcome, Slow-K is contraindicated in patients with severe renal impairment. If used in patients with mild to moderate renal impairment, extreme caution along with frequent serum potassium monitoring is recommended.
Preclinical data do not support a special hazard for humans based on conventional studies of acute toxicity, repeated dose toxicity, genotoxicity, carcinogenic potential and toxicity to reproduction.
The acute and repeated-dose oral toxicity of potassium chloride (KCl) in animals is low. Gastrointestinal irritant effects have been observed in rhesus monkeys at high oral dosages of Slow-K. Some positive results in in vitro genotoxicity assays were attributed to very high concentrations of KCl. Carcinogenicity studies in rats administered KCl in-feed were negative. Limited information from oral developmental studies in rodents indicates there is no ill effect on offspring. There is no evidence from animal experiments that oral KCl exerts any teratogenic effects or reproductive toxicity which would be relevant to man.
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