Slow-K modified-release tablets contain the active ingredient potassium chloride. Slow-K is a type of medicine called a potassium supplement.

What is it used for?

  • Preventing and correcting a low level of potassium in the blood (hypokalaemia).

How does it work?

  • Slow-K modified-release tablets contain the active ingredient potassium chloride. Slow-K is a type of medicine called a potassium supplement.
  • Potassium is an essential element required by the body for normal functioning. It is consumed in the diet and is filtered out of the body by the kidneys. Supplements are not normally needed because we normally get enough through our everyday diets.
  • However, some medicines cause the body to lose excessive amounts of potassium (for example loop or thiazide diuretics, long-term corticosteroids, theophylline or carbenoxolone).
Some medical conditions also cause potassium loss (for example chronic diarrhoea, kidney disease, liver cirrhosis or heart failure).
  • In these situations potassium supplementation helps prevent severe potassium loss (hypokalaemia) and its associated symptoms. These include muscle weakness, dizziness and disturbances in the heart rhythm.
  • Potassium supplements are used to prevent and correct low levels of potassium in the blood.
  • Slow-K tablets are a 'modified-release' form of potassium chloride that are designed to release the potassium slowly as they pass through the gut. They are intended for use by people who dislike taking effervescent or syrup forms of potassium.
  • How do I take it?

    • Slow-K tablets should be taken during a meal whilst sitting upright or standing.
    • Slow-K tablets must be swallowed whole with a full glass of water. The tablets should not be broken, crushed or chewed, as this would damage the modified-release action.
    • The number of tablets that you need to take each day will depend on your blood level of potassium; this will be assessed by a blood test. It is important to follow the instructions given by your doctor and the directions printed on the dispensing label. If your doctor wants you to take more than two tablets a day, the total number of tablets should be split into two or three doses, rather than taking all the tablets at the same time. Ask your pharmacist for further advice.

    Warnings

    • You will need to have regular blood tests to check your potassium level and levels of other salts while you are taking this medicine. Your doctor may also want you to have a regular ECG to check your heart rhythm.
    • You should avoid using dietary salt substitutes such as Lo-Salt or Ruthmol while you are taking potassium supplements, particularly if you have kidney failure. These products contain potassium instead of sodium and could cause the level of potassium in your blood to rise too high.
    • If you experience severe vomiting, abdominal pain or flatulence, or notice blood in your stools or black, tarry stools while taking this medicine you should see your doctor immediately.

    Use with caution in

    • Elderly people.
    • People with decreased kidney function.
    • People with heart disease.
    • People with a hiatus hernia.
    • People with a history of peptic ulcer.
    • People taking anticholinergic medicines that slow down the passage of food etc through the gut.

    Not to be used in

    • People with high levels of potassium in their blood (hyperkalaemia).
    • Uncontrolled Addison's disease.
    • Severe dehydration.
    • People with increased acid levels in their blood (metabolic acidosis).
    • Severely decreased kidney function with decreased urine production (oliguria).
    • Slow-K tablets are not suitable for correcting potassium levels in people with a total or partial blockage in the gut.
    • Slow-K tablets contain sucrose and should not be used by people with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency.
    • Slow-K tablets are not recommended for correcting potassium levels in children.
    • This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

    If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

    Pregnancy and breastfeeding

    Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

    • This medicine is not known to be harmful if used to correct low blood potassium levels during pregnancy, provided the mother's potassium level does not rise too high. However, as with all medicines it should be used with caution during pregnancy, and only if the expected benefit to the mother is greater than any possible risk to the developing baby. If it is used during pregnancy the mother's potassium level should be regularly checked. Seek further medical advice from your doctor.
    • Breast milk is naturally low in potassium. This medicine is not known to be harmful if used during breastfeeding, provided the mother's potassium level does not rise too high. As with all medicines it should be used with caution by breastfeeding mothers, and only if the expected benefit to the mother is greater than any possible risk to the baby. Ask your doctor for further advice.

    Label warnings

    • This medication is to be swallowed whole, not chewed.
    • This medication is to be taken with plenty of water.

    Side effects

    Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

    • Nausea and vomiting.
    • Abdominal pain.
    • Diarrhoea
    • Flatulence.
    • Obstruction or ulceration of the stomach or intestines.

    The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.

    For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

    How can this medicine affect other medicines?

    It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.

    Slow-K tablets increase the level of potassium in your blood. If this medicine is taken with other medicines that can increase blood potassium levels, this effect may be enhanced. Your doctor may want to monitor your blood potassium level if you take any of these medicines in combination with Slow-K:

    • ACE inhibitors, eg enalapril, captopril
    • aliskiren
    • angiotensin II receptor antagonists, eg losartan, valsartan
    • ciclosporin
    • drospirenone
    • heparin
    • non-steroidal anti-inflammatory drugs (NSAIDs), eg indometacin, diclofenac, ibuprofen
    • potassium-containing dietary salt substitutes such as Lo-Salt
    • potassium salts, eg potassium citrate for cystitis
    • potassium-sparing diuretics eg amiloride, spironolactone, triamterene
    • tacrolimus.

    References:

    http://www.netdoctor.co.uk/medicines/diet-and-nutrition/a7541/slow-k-potassium-chloride/

    https://www.nps.org.au/medical-info/medicine-finder/slow-k-slow-release-tablets

    http://www.rxlist.com/slow-k-drug.htm

    https://www.medicines.org.uk/emc/medicine/130

    https://www.drugs.com/pro/slow-k.html

    http://www.medicines.ie/cd/content/documents/06000/06049/SPC.6049.html