Potassium Supplements for Cats: Uses and Side Effects

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Potassium is a really important electrolyte, used by the body for multiple different functions and essential for health. While dietary deficiency is uncommon in cats, certain health disorders can cause low potassium levels in the body, leading to a need for suitable potassium supplements. There are a couple of different types of potassium supplements for cats, so let’s go through how they may be used, and situations where potassium supplementation should be avoided.

Potassium Supplements for Cats

Medication Type:

Potassium (in citrate, gluconate, chloride, and bicarbonate forms)

Medication Form:

Oral tablets, powder, and gel

Brand Names:

Tumil-K (gluconate), RenaKare (gluconate), RenaPlus (gluconate), RenalK (gluconate), Urocit-K (citrate), K-Plus Granules (citrate), NutriVed Granules (citrate)

Common Names:

Potassium citrate, potassium gluconate, potassium chloride.

Effects:

Increase potassium levels in the body or increase urine pH to prevent formation of calcium oxalate urinary stones.

Available Dosages:

Varies widely depending on the type of potassium salt (i.e citrate vs. gluconate) and the dosing form (tablet, powder, gel).

Potential Side Effects:

Hyperkalemia (high potassium), digestive upset – nausea, vomiting, diarrhea, ulceration

Precautions:

Kidney failure or kidney injury, heart disease, hemolytic (red blood cell loss) disease, acute or severe dehydration, GI motility impairment. Supplementation should not be started without a known potassium deficiency

Contraindications:

Known hyperkalemia (high potassium), urinary obstruction, GI obstruction, severe vomiting or diarrhea.

About Potassium Supplements for Cats

Potassium is an important electrolyte that serves many functions in the body, but especially for nerves, muscles, and the heart. Cats with very low or high potassium can develop effects on nerve, muscle, and heart function. Cats obtain potassium through their diet. Common dietary sources include red meat, poultry, and fish. Dietary deficiencies of potassium are uncommon.

Potassium supplements for cats may be needed in cases where potassium levels in the body are low. Cats with low potassium may need supplementation depending on how severe the loss is and the reason behind low levels. There are a couple of situations where potassium levels may be low in cats, a condition called hypokalemia.

• Chronic kidney disease is the single most common cause in cats, most often at IRIS stage II-III
• Severe vomiting or diarrhea
• Primary hyperaldosteronism, where high levels of the hormone aldosterone can lead to loss of potassium through the kidneys
• Periodic hypokalemia seen in Burmese cats and similar breeds as an inherited disorder
• Poor appetite or anorexia
• Other diseases such as hyperthyroidism, diabetic ketoacidosis
• Secondary to medications like diuretics or insulin

Potassium supplements may also be used as a way of reducing the risk for cats developing calcium oxalate bladder stones.

Three Common Potassium Supplements for Cats

There are three main forms of potassium salts that may be used in cats for oral supplementation.

1. Potassium Citrate

This form is used most often to help prevent the formation of calcium oxalate stones for cats that are at a higher risk. The citrate is metabolized to bicarbonate, which helps to increase urine pH, an environment less favorable for calcium stone formation. An example of this type of supplement is K-Plus.

While it may be useful for low potassium levels in the body, there is little to no research evidence of relevance to support its use in these cases.

2. Potassium Gluconate

This form is used most often for conditions leading to low blood levels of potassium in the body. Examples include RenaPlus, RenaKare and Tumil-K.

3. Potassium Chloride

Potassium chloride is used most often in an injectable form to treat pets with severe hypokalemia in a veterinary setting. It’s not commonly used in an oral form to treat low potassium levels as its taste and palatability appears to be poor. One study did suggest that KCl in the diet lowers urine concentration, increases urine volume, and was associated with lower risk of calcium stone formation.

Other forms of potassium include potassium acetate, another injectable form, and potassium bicarbonate. Potassium bicarbonate would be most useful for prevention of calcium oxalate stones, but is uncommonly used because potassium citrate is already metabolized by the liver into a bicarbonate form.

Potassium Supplement Dosing Information for Cats

Any information provided here is not intended to replace a veterinary exam and an attending veterinarian’s assessment of your cat’s health and treatment recommendations.

There is no known FDA approval for potassium supplements for cats. Dosing is largely based on a cat’s particular health situation, limited research studies, and a veterinarian’s clinical experience. If used inappropriately, potassium supplementation can have significant risks, which will be reviewed shortly. Potassium supplementation should always be based on known potassium blood levels.

A cat’s blood potassium level should be maintained between 3.5-5.5 milliequivalents per liter (mEq/L). Cats with a potassium level below 3 may be considered mildly hypokalemic. Potassium should be carefully monitored so that it does not exceed 6. Potassium levels that surpass 7.5 can be life-threatening, affecting heart muscle function.

In cases of chronic kidney disease, the most common cause of low potassium in cats, the International Society for Feline Medicine suggests treating with 1-3 mEq per cat every 12 hours. Many supplements provide dosing in mEq, but 2 mEq of calcium gluconate is about equivalent to 468mg.

Because of the significant risks that are possible, many potassium gluconate supplements marketed as a medication require a prescription (e.g. RenaPlus potassium gluconate tablets). Supplements marketed as a food additive (e.g. RenalK+) do not – but can still carry similar risks.

Once starting a potassium supplement, potassium levels in the blood need to be checked to determine any need for dosing adjustment.

How To Administer Potassium Supplements to Cats

Tablet forms of potassium may be the most accurate to dose but can be harder to give than powder and gel forms. Creative Cat Studio / Shutterstock.com

Most potassium supplements in the forms of potassium citrate or potassium gluconate come in tablet, powder, or gel forms. I find that the powder and gel forms are the most straightforward approaches for cats, but many cats can be administered pills with a little practice.

Tablet forms (like RenaPlus and Tumil-K tablets) may provide the most accurate dosing, but may be the most difficult to give. Powder forms allow for mixing with canned or soft food. This form is available for most supplements, including Tumil-K powder, RenaKare, RenalK+, and K-Plus.

The gel forms (Renal K gel, RenaPlus gel, K-Plus gel) provide an option where the supplement doesn’t have to be mixed or associated with food. The gel can be given directly by mouth, or may be applied to a cat’s paw, inducing them to lick the gel off.

Side Effects of Potassium Supplements for Cats

Because of its effects on nerve and muscle function, significant risks can be associated with potassium supplementation when inappropriate or unnecessary.

Generally, the most common side effects seen with potassium supplementation in otherwise healthy cats is digestive upset including vomiting, diarrhea, and poor appetite.

Supplementing too much potassium in an otherwise healthy cat may lead to signs of hyperkalemia, including vomiting and diarrhea, heart arrhythmias, weakness, and collapse. This is unlikely to occur in otherwise healthy cats when following product label instructions.

Other side effects may be associated with other diseases a cat has. These disorders may serve as contraindications to potassium supplementation (where it should not be used) or require significant caution. Common contraindications include:

• Hyperkalemia (high potassium): This is most often cats with a current urinary obstruction. Cats at risk should be monitored very carefully. While potassium citrate may reduce the risk of calcium oxalate stones, increasing the urine pH can lead to a higher risk for magnesium-ammonium-phosphate (struvite) stones. If your cat is showing signs of urinary difficulty, it may be best to discontinue a potassium supplement pending a veterinary exam to determine the underlying cause.
• Kidney Failure and Acute Kidney Injury (AKI): While potassium supplementation is needed most often in cats with chronic kidney disease (CKD), it should be used cautiously or not used at all when kidney disease is severe or if the kidneys are experiencing an acute injury (such as from a toxin or urinary obstruction). In these cases, the kidneys have little to no function and supplementing excess potassium may lead to very high levels in the bloodstream and hyperkalemia.
• Significant Dehydration: This may be defined as being 8-10% or greater dehydrated. This may occur for numerous reasons and is usually associated with a very ill cat.
• Advanced heart disease and heart failure: The heart is very sensitive to changes in potassium. In cases of advanced cardiac disease or heart failure, potassium excretion from the body may be impaired. Supplementing may lead to hyperkalemia.
• Uncontrolled Diabetes Mellitus: Cats with uncontrolled diabetes may be very ill and dehydrated. Insulin can also affect potassium moving from the bloodstream into cells. Uncontrolled or inappropriate insulin use may lead to fluctuating potassium levels that are difficult to interpret.
• Delayed stomach emptying conditions or intestinal obstruction: Prolonged contact with potassium tablets in a GI tract that is not moving things through properly can lead to GI mucosal damage, ulceration, and bleeding.
• Poor liver function: for potassium citrate specifically, poor liver function may affect the metabolism of citrate to bicarbonate.

Overdose and Emergencies

Overdoses are less common with oral supplementation, but this may depend on underlying conditions your cat has. If your cat develops severe kidney failure for example, any supplementation may be considered an overdose.

Signs seen with overdoses are the same as those seen with hyperkalemia, including:

• Digestive upset
• Gastrointestinal bleeding
• Muscle weakness
• Lethargy

If you are ever concerned that your kitty may have developed side effects while using a potassium supplement, or if an overdose is suspected, make sure to contact your veterinarian, the ASPCA Animal Poison Control Center (1-888-426-4435), or Pet Poison Helpline (1-855-764-7661) immediately for further advice.

Potential Drug Interactions With Potassium Supplements

There are a few medications that may interact with potassium supplements. This list does not necessarily mean medications cannot be used together with potassium supplements, but should be used carefully. Always check with your veterinarian for clarification regarding medications your cat is currently on:

• Angiotensin converting enzyme (ACE) inhibitors
• Angiotensin Receptor Blockers (ARBs) (telmisartan)
• Digoxin
• Potassium sparing diuretics (spironolactone)
• Non-steroidal anti-inflammatory drugs (NSAIDs) (meloxicam, robenacoxib)

The following are more specifically risks associated with potassium citrate use for increasing urine pH:

• Aluminum-containing phosphate binders
• Antacids containing aluminum
• Anticholinergic medications (tricyclic antidepressants like amitriptyline)
• Aspirin
• Fluoroquinolone antibiotics (marbofloxacin, pradofloxacin)
• Lithium
• Methenamine
• Opioids (buprenorphine, tramadol)
• Phenobarbital
• Quinidine
• Tetracyclines

How To Store Potassium Supplements for Cats

Pay close attention to any specific instructions by individual manufacturers for how to store their products.

In general, potassium gluconate should be stored in tight, light-resistant containers at room temperature (59 degrees F to 86 degrees F). Potassium citrate may also be stored similarly at room temperature but with a more narrow temperature window of 68 degrees F to 77 degrees F.

Drug Dosing Disclaimer: We can only provide doses for medications that are FDA-approved for use in cats and only as the label guidelines dictate. For medications that are used off-label, we can only provide guidelines and safety information. Safe and appropriate dosing for off-label medications can only be determined by a primary care veterinarian.

We encourage you to work with your veterinarian to determine if a particular medication is appropriate for your cat. Changing or adjusting a dose for your cat on your own without consulting with a veterinarian can carry risk. We do not encourage the use of medications prescribed for human use in pets without first consulting with a primary care veterinarian.