SLOW-K

Clinical safety rating: caution

Comprehensive clinical and safety monograph for SLOW-K (SLOW-K).

How it works

Potassium is the major intracellular cation; essential for maintenance of intracellular tonicity, transmission of nerve impulses, contraction of cardiac, skeletal, and smooth muscle, and maintenance of normal renal function.

What the body does with it

Metabolism	Potassium is absorbed in the small intestine and excreted primarily by the kidneys via a process of glomerular filtration, distal tubular secretion, and reabsorption; minimal metabolism.
Excretion	Primarily renal (>90%) as potassium ions; minimal biliary/fecal elimination (<5%)
Half-life	Not applicable; potassium is an electrolyte with no defined elimination half-life; distribution half-life ~2-4 hours
Protein binding	0% (free ion)
Volume of Distribution	0.15-0.2 L/kg in adults; approximates extracellular fluid volume
Bioavailability	Oral: 100% (complete absorption of potassium chloride in solution; solid formulations variable)
Onset of Action	Oral: 1-2 hours for rise in serum potassium; intravenous: immediate
Duration of Action	Oral: 4-6 hours for sustained release formulation; intravenous: as long as infusion continues

Classification & Brands

Dosing & administration

Adults: 600-2400 mg potassium chloride (8-32 mmol K+) orally per day in divided doses, usually 1-2 tablets twice daily. Maximum single dose: 20 mmol. Route: oral. Frequency: 1-4 times daily.

Dosage form	TABLET, EXTENDED RELEASE
Renal impairment	eGFR 30-60 mL/min: Reduce dose by 25-50% and monitor serum potassium. eGFR <30 mL/min: Contraindicated unless hypokalemia confirmed and cautious use with frequent monitoring. Avoid in severe renal impairment.
Liver impairment	No specific Child-Pugh based adjustments. Use with caution in cirrhosis or hepatic failure due to risk of hyperkalemia; monitor serum potassium. Consider dose reduction if renal function is compromised.
Pediatric use	Neonates and infants: 1-2 mmol/kg/day orally in divided doses. Children: 1-3 mmol/kg/day orally in divided doses, maximum 2 g/day (27 mmol). Adjust based on serum potassium levels. Use liquid or slow-release formulations cautiously in children <5 years.
Geriatric use	Start at lower end of adult dosing (e.g., 600-1200 mg/day). Monitor renal function and serum potassium frequently due to age-related decline in GFR. Avoid in patients with CrCl <30 mL/min unless severe hypokalemia.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for SLOW-K (SLOW-K).

Breastfeeding	Potassium is a normal component of breast milk; levels are regulated by maternal homeostasis. M/P ratio not established; potassium chloride supplementation does not significantly alter breast milk content. Compatible with breastfeeding; monitor maternal potassium levels to avoid extreme deviations.
Teratogenic Risk	No evidence of teratogenicity; potassium chloride is a normal plasma constituent. First trimester: no increased risk of major malformations. Second/third trimester: use with caution to avoid hyperkalemia, which may cause fetal arrhythmia. Supplemental potassium does not cross placenta in significant amounts to cause fetal harm when maternal serum levels are maintained in normal range.

Warnings & precautions

■ FDA Black Box Warning

Potassium chloride tablets can cause intestinal and esophageal ulceration, perforation, and obstruction, especially when slow-release formulations are used. Use with caution in patients with esophageal compression or delayed gastric emptying.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hyperkalemia","Severe renal impairment (oliguria, anuria, azotemia)","Concurrent use of potassium-sparing diuretics (e.g., amiloride, spironolactone, triamterene)","Severe hemolytic reactions","Adrenocortical insufficiency (Addison's disease)","Esophageal compression or delayed gastric emptying"]

Clinical Precautions

Precautions

["Risk of hyperkalemia, especially in patients with renal impairment or on ACE inhibitors, ARBs, potassium-sparing diuretics","Gastrointestinal adverse effects: nausea, vomiting, abdominal pain, diarrhea, bleeding, ulceration, perforation","Avoid in patients with esophageal compression or delayed gastric transit","Use with caution in patients with cardiac disease, diabetes, or metabolic acidosis"]

Clinical Tips & Counseling

Drug interactions

Loading safety data…

SLOW-K

Clinical safety rating: caution

Comprehensive clinical and safety monograph for SLOW-K (SLOW-K).

How it works

What the body does with it

Metabolism	Potassium is absorbed in the small intestine and excreted primarily by the kidneys via a process of glomerular filtration, distal tubular secretion, and reabsorption; minimal metabolism.
Excretion	Primarily renal (>90%) as potassium ions; minimal biliary/fecal elimination (<5%)
Half-life	Not applicable; potassium is an electrolyte with no defined elimination half-life; distribution half-life ~2-4 hours
Protein binding	0% (free ion)
Volume of Distribution	0.15-0.2 L/kg in adults; approximates extracellular fluid volume
Bioavailability	Oral: 100% (complete absorption of potassium chloride in solution; solid formulations variable)
Onset of Action	Oral: 1-2 hours for rise in serum potassium; intravenous: immediate
Duration of Action	Oral: 4-6 hours for sustained release formulation; intravenous: as long as infusion continues

Classification & Brands

Dosing & administration

Adults: 600-2400 mg potassium chloride (8-32 mmol K+) orally per day in divided doses, usually 1-2 tablets twice daily. Maximum single dose: 20 mmol. Route: oral. Frequency: 1-4 times daily.

Dosage form	TABLET, EXTENDED RELEASE
Renal impairment	eGFR 30-60 mL/min: Reduce dose by 25-50% and monitor serum potassium. eGFR <30 mL/min: Contraindicated unless hypokalemia confirmed and cautious use with frequent monitoring. Avoid in severe renal impairment.
Liver impairment	No specific Child-Pugh based adjustments. Use with caution in cirrhosis or hepatic failure due to risk of hyperkalemia; monitor serum potassium. Consider dose reduction if renal function is compromised.
Pediatric use	Neonates and infants: 1-2 mmol/kg/day orally in divided doses. Children: 1-3 mmol/kg/day orally in divided doses, maximum 2 g/day (27 mmol). Adjust based on serum potassium levels. Use liquid or slow-release formulations cautiously in children <5 years.
Geriatric use	Start at lower end of adult dosing (e.g., 600-1200 mg/day). Monitor renal function and serum potassium frequently due to age-related decline in GFR. Avoid in patients with CrCl <30 mL/min unless severe hypokalemia.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for SLOW-K (SLOW-K).

Breastfeeding	Potassium is a normal component of breast milk; levels are regulated by maternal homeostasis. M/P ratio not established; potassium chloride supplementation does not significantly alter breast milk content. Compatible with breastfeeding; monitor maternal potassium levels to avoid extreme deviations.
Teratogenic Risk	No evidence of teratogenicity; potassium chloride is a normal plasma constituent. First trimester: no increased risk of major malformations. Second/third trimester: use with caution to avoid hyperkalemia, which may cause fetal arrhythmia. Supplemental potassium does not cross placenta in significant amounts to cause fetal harm when maternal serum levels are maintained in normal range.