Electrolyte (potassium)
Potassium is an essential mineral for the heart, muscles and nerves. Potassium chloride is used to replace potassium when it is low — for example due to diuretics, diarrhoea or vomiting. It is a serious medicine: taking too much (or with failing kidneys) can be dangerous for the heart.
Also known as: potássio, potassium, cloreto de potássio, Sando-K
Spironolactone + potassium: risk of severe hyperkalaemia.
Spironolactone is a potassium-sparing diuretic that antagonises aldosterone in the distal convoluted tubule, reducing renal potassium excretion. Concomitant potassium supplements (potassium chloride) additively increase the risk of hyperkalaemia, which can be severe and potentially fatal (ventricular arrhythmias, cardiac arrest). The risk is even higher in patients with renal impairment, diabetes or advanced age, and with other potassium-raising drugs (ACE inhibitors, ARBs, other potassium-sparing agents). The combination should generally be avoided; if clinically unavoidable (e.g., severe hypokalaemia in an already treated patient), use the lowest potassium dose, monitor serum potassium frequently and watch the ECG, warning the patient about symptoms such as muscle weakness, palpitations or paraesthesias.
Spironolactone + potassium: risk of severe, potentially fatal hyperkalaemia. Avoid the combination; if unavoidable, monitor serum potassium and ECG.
Spironolactone (potassium-sparing diuretic) reduces renal K+ excretion; additive supplementation may cause potentially fatal hyperkalaemia.
Serum potassium, ECG, renal function.
Weakness, arrhythmias, peaked T waves, cardiac arrest.
Avoid the combination; if unavoidable, monitor potassium frequently and stop the supplement.
DailyMed (FDA) — approved Spironolactone label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ac487ae2-e15f-4781-bae3-a03058cfcfe4 ; approved Potassium chloride label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=eb56a807-ea94-4edb-9811-a04b19568468 — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
ACE inhibitor + potassium: risk of hyperkalaemia (especially in renal impairment or diabetes).
Angiotensin-converting enzyme inhibitors (ACEIs) such as enalapril reduce aldosterone secretion and, with it, renal potassium excretion. Concomitant potassium supplements (potassium chloride) can lead to hyperkalaemia, especially in patients with renal impairment, diabetes, advanced age or taking other potassium-raising drugs (ARBs, potassium-sparing diuretics, NSAIDs). Potassium should be started cautiously, with monitoring of serum potassium and renal function after initiation or dose adjustment, and patients warned about hyperkalaemia symptoms (muscle weakness, fatigue, palpitations, paraesthesias).
ACE inhibitor + potassium: risk of hyperkalaemia, especially in renal impairment or diabetes. Monitor serum potassium.
ACE inhibitors reduce aldosterone and K+ excretion; potassium supplementation adds risk.
Serum potassium and renal function.
Weakness, paraesthesia, arrhythmias.
Monitor serum potassium; use potassium supplements with caution.
DailyMed (FDA) — approved Enalapril label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f103b9f9-e081-419d-a2d8-b86acda834dd ; approved Potassium chloride label: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=eb56a807-ea94-4edb-9811-a04b19568468 — additional reference: Prontuário Terapêutico do INFARMED (11th ed., 2012)
Salt substitutes contain potassium chloride and increase K+ intake.
Advise patients on potassium supplements not to use salt substitutes.
EMC-UK (MHRA) — approved Potassium chloride SmPC: https://www.medicines.org.uk/emc/product/959/smpc
Banana, spinach and pulses add potassium to supplementation.
Moderate potassium-rich foods during supplementation, especially in at-risk patients.
EMC-UK (MHRA) — approved Potassium chloride SmPC: https://www.medicines.org.uk/emc/product/959/smpc
Supplementation worsens pre-existing hyperkalaemia.
Monitor serum potassium and stop if needed.
EMC-UK (MHRA) — approved Potassium chloride SmPC: https://www.medicines.org.uk/emc/product/959/smpc
Renal potassium excretion is reduced, risking hyperkalaemia.
Avoid potassium supplements in severe renal impairment without monitoring.
EMC-UK (MHRA) — approved Potassium chloride SmPC: https://www.medicines.org.uk/emc/product/959/smpc
Maintaining normokalaemia is important in pregnancy; supplementation is safe when indicated.
Replace potassium only when indicated, with monitoring.
Compatible with breastfeeding.
No specific additional contraception.
EMC-UK (MHRA) — approved Potassium chloride SmPC: https://www.medicines.org.uk/emc/product/959/smpc
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Replaces intracellular potassium, correcting hypokalaemia and its consequences (arrhythmias, muscle weakness, paralytic ileus). Potassium is the principal intracellular cation (150–160 mEq/L) versus 3.5–5 mEq/L in plasma, a gradient maintained by Na⁺/K⁺-ATPase.
The potassium ion participates in maintenance of intracellular tonicity, nerve impulse transmission, contraction of cardiac, skeletal and smooth muscle, and normal renal function. The transmembrane gradient is essential for resting potential and excitability.
Extended-release tablets: potassium chloride is completely absorbed before leaving the small intestine; the wax matrix is not absorbed and is excreted in faeces. The extent of absorption is similar to that of a true solution.
Potassium is not metabolised; it is eliminated mainly by the kidneys (distal secretion regulated by aldosterone) and, to a lesser extent, by the gastrointestinal tract.
The half-life of plasma potassium is hours (rapid distribution); renal elimination adapts to intake, with daily excretion of about 90% of intake in individuals with normal renal function.
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
