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Slow-K Tablets 600 mg

Last Updated on eMC 28-May-2015 View changes  | Alliance Pharmaceuticals Contact details

1. Name of the medicinal product

Slow-K 600mg prolonged-release tablets

2. Qualitative and quantitative composition

Each tablet contains 600mg potassium chloride as active substance equivalent to 8 mmol potassium ion (K+).

Excipients with known effect:

Sucrose 96.425mg.

For the full list of excipients, see section 6.1.

3. Pharmaceutical form

Prolonged-release tablet.

Pale orange, round, biconvex, sugar-coated tablets.

4. Clinical particulars
4.1 Therapeutic indications

The correction and/or prevention of hypokalaemia in those patients who cannot tolerate and/or refuse to take liquid or effervescent potassium chloride, or when there is a problem of compliance with these preparations.

4.2 Posology and method of administration

For oral administration.

Slow-K is advised to be given with meals to minimize gastric irritation.

It is important that the tablets should be swallowed whole, with fluid, whilst the patient is sitting upright.


The dosage of Slow-K should be adapted to the cause, degree and duration of potassium depletion. 2 to 3 tablets daily are usually an adequate supplement. In states of severe potassium deficiency, a higher dose of 9 to 12 tablets daily may be needed.

If the dosage exceeds 16mmol K+ (2 tablets) it should be taken in divided doses. Where intermittent diuretic therapy is being used, it is advisable to give Slow-K on intervening days between administration of the diuretic. The response to treatment should preferably be monitored by repeat determination of plasma potassium and Slow-K continued until the hypokalaemia has been corrected.

Renal impairment:

In patients with a Glomerular Filtration Rate (GFR) <60mL/min, Slow K should be given with extreme caution, with frequent serum potassium monitoring due to increased risk of hyperkalaemia. Slow-K is contraindicated in patients with a GFR <20mL/min (see also section 4.3 Contraindications).

Hepatic impairment:

No studies have been performed in hepatically impaired patients.

Paediatric population: Safety and effectiveness in children has not been established, Slow-K is therefore not recommended for paediatric use.

Older people: Slow-K should be given with caution and with frequent serum potassium monitoring due to increased risk of hyperkalaemia.

4.3 Contraindications

Hypersensitivity to potassium administration, eg hyperkalaemic periodic paralysis, congenital paramyotonia, or hypersensitivity to any of the excipients.

Kidney disease where GFR <20mL/min (even when not yet associated with manifest hyperkalaemia) (see also section 4.2), untreated Addison's Disease, hyporeninaemic hypoaldosteronism, acute dehydration, hyperkalaemia and conditions involving extensive cell destruction (eg severe burns).

All solid forms of potassium medication are contra-indicated in the presence of obstructions in the digestive tract (eg resulting from compression of the oesophagus due to dilation of the left atrium or from stenosis of the gut).

In cases of metabolic acidosis, the hypokalaemia should be treated not with potassium chloride but with an alkaline potassium salt (eg potassium bicarbonate).

Concomitant treatment with potassium sparing diuretics (eg triamterene and amiloride) and aldosterone antagonists (eg spironolactone and eplerenone (see also section 4.5 Interactions with other medicinal products and other forms of interaction).

4.4 Special warnings and precautions for use

If a patient under treatment with Slow-K develops severe vomiting, severe abdominal pains or flatulence, or gastro-intestinal haemorrhage, the preparation should be withdrawn at once, because in the presence of an obstruction it could conceivably give rise to ulceration or perforation (see also section 4.8 Undesirable effects).

Oral potassium preparations should be prescribed with particular caution in patients with a history of peptic ulcer.

Caution should be exercised when prescribing solid oral potassium preparations, particularly in high dosage, in patients concurrently receiving anticholinergics, because of their potential to slow gastro-intestinal motility (see also section 4.5 Interactions with other medicinal products and other forms of interaction).

Patients with ostomies or other conditions which alter intestinal transit times are better treated with other forms of potassium salts.

In patients suffering from impaired renal function, special care should be exercised when prescribing potassium salts owing to the risk of their producing hyperkalaemia (see section 4.2). Monitoring of the serum electrolytes is particularly necessary in patients with diseases of the heart or kidneys.

In some patients, diuretic-induced magnesium deficiency will prevent restoration of intracellular deficits of potassium, so that hypomagnesaemia should be corrected at the same time as hypokalaemia.

Patients with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency should not take this medicine.

4.5 Interaction with other medicinal products and other forms of interaction

Concomitant treatment with potassium-sparing diuretics (e.g. triamterene and amiloride) and aldosterone antagonists (e.g. spironolactone and eplerenone) is contraindicated (see section 4.3 Contraindications). Drugs which interfere with potassium excretion may promote hyperkalaemia when given together with Slow-K.

Combined treatment with the following increase the risk of hyperkalaemia: ACE inhibitors, angiotensin-II-receptor antagonists, ciclosporin, NSAIDs, β-blockers, heparin, digoxin, direct renin inhibitors (e.g. aliskerin), proton pump inhibitors. Thus, caution should be exercised in their concomitant use.

Caution should be exercised when prescribing solid oral potassium preparations, particularly in high dosage, in patients concurrently receiving anticholinergics, because of their potential to slow gastro-intestinal motility (see also section 4.4 Special warnings and precautions for use).

4.6 Fertility, pregnancy and lactation


For Slow-K no clinical data on exposed pregnancies are available.

There is no indication in animal studies of direct or indirect harmful effects with respect to pregnancy, embryonal/foetal development, parturition or postnatal development (see also section 5.3 Preclinical safety data).

Pregnancy is associated with gastrointestinal hypomotility. In pregnant women, therefore, solid forms of oral potassium preparations should be given to pregnant women only if clearly needed.


The excretion of potassium in milk has not been studied in animals or human.

The normal K+ content of human milk is about 13mmol/litre. Since oral potassium becomes part of the body's potassium pool, provided this is not excessive, Slow-K can be expected to have little or no effect on the potassium level in human milk.

Slow-K should only be given during breast-feeding when the expected benefit to the mother outweighs the potential risk to the baby.


No data is available.

4.7 Effects on ability to drive and use machines

None known.

4.8 Undesirable effects

The following adverse drug reactions have been derived from post-marketing experience with Slow-K. Because these reactions are reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency which is therefore categorized as not known. Adverse drug reactions are listed according to system organ classes in MedDRA. Within each system organ class, ADRs are presented in order of decreasing seriousness.

Gastrointestinal disorders

Gastrointestinal obstruction, gastrointestinal haemorrhage, gastrointestinal ulcer, with or without perforation of the upper or lower GIT1

Gastro-intestinal disturbances (nausea, vomiting, abdominal pains, diarrhoea)2

Skin and subcutaneous tissue disorders


Skin rash


Metabolism and nutrition disorders


1usually associated with other factors known to predispose a patient to these effects (eg delayed GIT transit time, obstruction of GIT).

2necessitating either a reduction in dosage or withdrawal of medication (see Section 4.4 “Special warnings and precautions for use”).

3may develop in patients having difficulty with either renal potassium excretion or potassium metabolism.

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 suspect adverse reactions via the Yellow Card Scheme. Website:

4.9 Overdose

General features:

Nausea, vomiting and abdominal pain. Patients may deteriorate rapidly. Gastritis and gastric/ small bowel ulceration may occur.

Cardiac effects:

Hypotension, shock, cardiac conduction abnormalities and dysrhythmias are the major hazards, particularly ventricular tachycardia and fibrillation. ECG changes include PR and QRS prolongation, peaked T waves and disappearance of P waves.

Neuromuscular effects:

Paraesthesiae, convulsions, areflexia, flaccid paralysis of striated muscle leading possibly to paralysis and respiratory arrest.


• Where the practical expertise exists, consider gastric lavage within 1 hour of ingestion of 300 mg/kg potassium (4 mmol/kg K+), providing the airway can be protected.

NOTE: Activated charcoal does not adsorb potassium.

• In all cases of suspected ingestion, measure U&Es and creatinine urgently. Monitor cardiac rhythm. In all patients the potassium concentration should be repeated at regular intervals after an acute overdose (i.e. 2-3 hourly if elevated). Intravenous fluids should be administered to all patients.

• Perform a 12 lead ECG and examine carefully for potassium-induced toxicity (PR and QRS prolongation, peaked T waves, disappearance of P waves). Manage QRS prolongation conventionally.

• All patients should be observed for at least 12 hours after ingestion.

• Treat severe hyperkalaemia conventionally.

• If at any time the potassium concentration is more than 6.5 mmol/L or ECG changes are present the following treatment options should be considered:

o Paediatric cases (children less than 12 years) early discussion with local paediatric teams is recommended.

o Discuss with local poisons information service.

• Haemodialysis or haemofiltration: If hyperkalaemia is not improving with conventional measures or there are life threatening arrhythmias or evidence of renal failure then haemodialysis or haemofiltration should be considered

5. Pharmacological properties
5.1 Pharmacodynamic properties

Pharmacotherapeutic group: Potassium supplement

ATC code: A12 BA01

The potassium chloride in Slow-K is finely distributed in a neutral wax base, from which it is gradually released over a period of 3 to 6 hours during its passage through the digestive tract. This special form of potassium substitution therapy is designed to avoid high localised concentrations of potassium chloride which might irritate or damage the mucosa. The potassium chloride in Slow-K is completely absorbed in the intestinal tract.

5.2 Pharmacokinetic properties


The potassium chloride in Slow-K has been shown to be completely absorbed; occasionally patients may notice “ghost” tablet cores in the faeces, these do not contain any potassium.

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 to 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.

Older people:

No pharmacokinetics studies of potassium chloride are reported in the elderly population. However, these patients are more likely to develop hyperkalaemia due to physiological changes, and reduced renal function.

Paediatric population:

No pharmacokinetics studies of potassium chloride are reported in the paediatric population.

Hepatic impairment:

No pharmacokinetics studies of potassium chloride are reported in patients with hepatic impairment.

Renal impairment:

Potassium is almost completely excreted via urine and its excretion rate correlates with the glomerular filtration rate. Considering the possibility of hyperkalaemia in these patients and severity of outcome, Slow-K is contraindicated in patients with a GFR <20mL/min. If used in patients with a GFR <60mL/min, extreme caution along with frequent serum potassium monitoring is recommended.

5.3 Preclinical safety data

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 developmental studies in rodents indicates there is no ill effect on offspring. There is no evidence from animal experiments that KCl exerts any teratogenic effects or reproductive toxicity which would be relevant to man.

6. Pharmaceutical particulars
6.1 List of excipients

Cetostearyl alcohol


Magnesium stearate


Titanium dioxide (E171)



Red iron oxide (E172)

Yellow iron oxide (E172)

Carnauba wax

6.2 Incompatibilities

None known.

6.3 Shelf life

5 years.

6.4 Special precautions for storage

Do not store above 30°C. Keep the container tightly closed.

6.5 Nature and contents of container

Polypropylene Securitainer with polyethylene cap containing 100 tablets.

6.6 Special precautions for disposal and other handling


Administrative data
7. Marketing authorisation holder

Alliance Pharmaceuticals Limited

Avonbridge House

Bath Road



SN15 2BB

8. Marketing authorisation number(s)


9. Date of first authorisation/renewal of the authorisation

25 June 1998

10. Date of revision of the text


Discontinued Items

The preparations being discontinued are:

  • Slow-K 600mg tablets (Alliance Pharmaceuticals Ltd)

The pharmaceutical company has decided to discontinue the product and so it may not be available in the future.  This document has been left on the eMC for information purposes.


Company contact details

Alliance Pharmaceuticals

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Avonbridge House, Bath Road, Chippenham, Wiltshire, SN15 2BB


+44 (0)1249 466 977


+44 (0)1249 466 966

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Active ingredients

potassium chloride

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