Your child needs to take the medicine called potassium (say: poe-TASS-ee-um). This information sheet explains what potassium does, how to give it, and what side effects or problems your child may have when he or she takes this medicine.

What is potassium?

Your child's body needs potassium to work properly. Potassium supplements (both liquids and tablets) may be needed by patients who do not have enough potassium. This may be because they do not have enough potassium in their regular diet or have lost too much potassium because they are sick or are taking certain medicines.

You may hear potassium called by its brand names: K-10®, K-lyte®, K-Dur®, Micro-K®, Apo-K®, Kaochlor® or Slow-K®.

Potassium comes as fizzy dissolving tablets, long-acting tablets or capsules, powders, and as a liquid.

Before giving potassium to your child

Tell your doctor if your child has:

  • an allergy to potassium supplements

Talk with your doctor or pharmacist if your child has any of the following conditions. Precautions may need to be taken with this medicine if your child has:

  • severe or continuing dehydration (excessive loss of body water)
  • diabetes
  • heart disease
  • stomach ulcers
  • kidney disease
  • a blockage in the throat or intestine
  • high potassium levels (hyperkalemia)
  • Addison’s disease (underactive adrenal glands)

How should you give your child potassium?

Follow these instructions when you give your child potassium:

  • Give your child potassium for as long as your doctor or pharmacist tells you, even if your child seems well. Talk to your child's doctor before you stop giving potassium for any reason.
  • Give the potassium supplement at the same time(s) every day, exactly as your child's doctor or pharmacist tells you. Pick a time that is easy for you so that you do not miss doses.
  • Give with food and a full glass of water to prevent an upset stomach.
  • If your child is taking liquid potassium, measure the dose of potassium carefully with the special spoon or syringe that the pharmacist gave you.
  • Give liquid potassium mixed with cold milk, juice, soft drink, or water (this also helps to hide the taste).
  • If your child is taking the long-acting capsule (Micro-K®), it can be swallowed whole with a full glass of water. Do not break, chew, or crush. You may also open the Micro-K® capsule and sprinkle the contents in applesauce or other soft food.
  • If giving potassium chloride through a feeding tube, feeds need to be stopped before giving potassium as it can clog the tube when combined with feeds.

What should you do if your child misses a dose of potassium?

  • Give the missed dose as soon as you remember.
  • If it is almost time for the next dose, skip the missed dose. Give the next dose at the regular time.
  • Do not give your child 2 doses to make up for 1 missed dose.
    What are the possible side effects of this medicine?

Your child may have some of these side effects while he or she takes potassium. Check with your child's doctor if your child continues to have any of these side effects, and they do not go away, or they bother your child:

  • upset stomach
  • throwing up
  • watery bowel movements (diarrhea)
  • mild stomach pain or discomfort
  • passing gas

Most of the following side effects are not common, but they may be a sign of a serious problem. Call your child's doctor right away or take your child to Emergency if your child has any of these side effects:

  • confusion or extreme dizziness
  • difficult breathing
  • uneven or slow heartbeat
  • black bloody bowel movements (stools)
  • painful swallowing
  • numbness, tingling, or burning feeling in the hands, feet, or lips
  • muscle weakness or heaviness in the legs

What safety measures should you take when your child is using potassium?

Keep all appointments at the clinic or doctor’s office so that the doctor can check your child’s response to potassium. The doctor may need to change the dose so that your child is getting the right amount.

Your child may need to get his or her blood work done regularly, so that the doctor can check your child's blood levels of potassium.

Talk to your child’s doctor before using a salt substitute or low-sodium or low-salt products. Many of these products contain potassium. Taking too much potassium may cause unwanted effects.

Check with your child’s doctor or pharmacist before giving your child any other medicines (prescription, non-prescription, herbal, or natural products). Several other medicines can affect potassium levels, so please tell your doctor if your child takes medication for high blood pressure or the heart, especially digoxin, water tablets (diuretics), and ACE inhibitors.

What other important information should you know about potassium?

Keep a list of all medications your child is on and show the list to the doctor or pharmacist.

Do not share your child’s medicine with others. Do not give anyone else’s medicine to your child.

Make sure you always have enough potassium to last through weekends, holidays, and vacations. Call your pharmacy at least 2 days before your child runs out of medicine to order refills.

Keep potassium at room temperature in a cool, dry place away from sunlight. Do NOT store it in the bathroom or kitchen.

Do not keep any medicines that are out of date. Check with your pharmacist about the best way to throw away outdated or leftover medicines.

Keep potassium out of your child’s sight and reach and locked up in a safe place. If your child takes too much potassium, call the Ontario Poison Centre at one of these numbers. These calls are free.

  • Call 416-813-5900 if you live in Toronto.
  • Call 1-800-268-9017 if you live somewhere else in Ontario.
  • If you live outside of Ontario, call your local Poison Information Centre

Disclaimer: The information in this Family Med-aid is accurate at the time of printing. It provides a summary of information about potassium and does not contain all possible information about this medicine. Not all side effects are listed. If you have any questions or want more information about potassium, speak to your health care provider.

Lori Chen, BScPhm, RPh, ACPR
Elaine Lau, BScPhm, PharmD, MSc, RPh