What are the indications for potassium supplementation in patients with hypokalaemia, and what forms are available?

Indications for potassium supplementation in hypokalaemia:

• Oral potassium supplementation is recommended for patients with serum potassium concentrations below 3.5 mmol/L, even if asymptomatic, especially in those with cardiovascular disease to prevent adverse events such as ventricular arrhythmias and death.
• Patients with hypertension, cardiac dysrhythmias, or chronic heart failure should maintain potassium levels at least 4.0 mmol/L, and supplementation is indicated to achieve this target.
• Severe hypokalaemia (<2.5 mmol/L), symptomatic hypokalaemia (e.g., paralysis, respiratory failure, severe weakness), or hypokalaemia with clinical signs of hypovolaemia or metabolic disturbances require urgent hospital admission and intravenous potassium supplementation.
• Oral supplementation is preferred in patients who can tolerate it and do not have diabetic ketoacidosis or hyperosmolar hyperglycaemic state; intravenous potassium chloride is used when oral intake is not possible or in severe cases.
• Correction of hypomagnesaemia is important as hypokalaemia often coexists with it and potassium correction may fail without magnesium replacement.
• Referral to an endocrinologist is advised if oral potassium is not tolerated or if the cause of hypokalaemia is unclear, especially in cases of potassium redistribution.

Forms of potassium supplementation available:

• Oral potassium chloride is the preferred form for supplementation due to its efficacy in correcting chloride depletion and metabolic alkalosis, and it raises serum potassium faster than potassium bicarbonate.
• Intravenous potassium chloride is used in severe hypokalaemia, symptomatic patients, or when oral supplementation is not feasible.
• Oral magnesium supplementation may be required concurrently if hypomagnesaemia is present, but caution is needed due to potential gastrointestinal side effects.

Monitoring of serum potassium is essential, with repeat measurements 3–4 days after starting supplementation and again after 2 weeks or sooner based on clinical judgment to avoid overcorrection or rebound hyperkalaemia.

Adjustments in diuretic therapy (e.g., switching to potassium-sparing diuretics) may be considered to reduce potassium loss.

Overall, treatment aims to prevent life-threatening cardiac and neuromuscular complications by restoring safe potassium levels and addressing underlying causes.

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