Potassium (K) is one cationic (positively charged ion) electrolyte required by not only cats and dogs but also by other animals and even human beings.
On the other hand, excessive amounts will lead to feline hyperkalemia which can be life-threatening in case it is severely high levels of this electrolyte.
We have already looked functions of sodium in cats where we also noted the required amounts and much more. We will be dwelling more on the various supplements in the market.
Potassium for cats supplements
These are dietary supplements designed to help cats that do not get enough or requires extra potassium especially those that have a deficiency due to causes such as chronic kidney disease, among other reasons for deficiencies.
The main supplements are either in the form of potassium gluconate, citrate or chloride and they can be powders, tablets, liquids, gels, or even injectable solutions.
1. How to give them
To avoid side effects, you should distribute the dosage in their diets especially for those that are powdered or if in tablet form, crush it. However, those in gel forms may present challenges in mixing them with your feline’s food.
Oral administration is the most effective method. However, injections may be recommended due to problems such as malabsorption or GI problems.
The injectable ones are often diluted by adding them to fluids before they can be administered. During administration, expect a mild sting.
They are effective and will respond within a short time. However, hypomagnesemia or magnesium deficiency incidents may affect the response. Also, if oral ones do not work, your vet may consider injectable versions.
In terms of the different forms, they are all effective. For instance, one study indicated that potassium gluconate powder or tablets or citrate granules were equally effective in treating hypokalemia in cats with CKD.
Monitoring the potassium levels by your vet should be done after 24-48 hours in cases of CKD. Additionally, all cats should be checked after 7-14 days  to check if the level of this electrolyte is normal in their blood.
Therefore, be very careful with the use of potassium supplements since they may be too much making your feline to suffer from hyperkalemia.
4. When not to give them?
In general, these supplements should only be given after approval by your vet and when the K+ concentration is below normal parameters. The normal sodium level in blood should be between 3.5 and 5.5 mEq/L.
Therefore, if it goes way below 3.5 mEq/L, they can have the mineral supplemented. Also, they can be used if the creatinine level goes beyond 500 mmol/L (6mg/dl) notes Felinecrf.org
Types and brands of potassium supplements
If you are looking for these supplements, the common types you will get in the market include the following:
1. Potassium gluconate for cats
It is the most recommended for oral supplementation, which most people use and it causes the least gastric irritation.
Dosages will depend on the severity of hypokalemia, cat size, and other factors. Your vet will help you determine the ideal dosage.
Popular brands include
a). Renal K+
It comes in gel and powder forms both of which are highly palatable and contains vitamin B complex.
b). Amino B+K
Features bacon flavor with vitamin B added as well as a small amount of iron. It comes in a palatable liquid form.
There are also potassium gluconate formulations for humans which you should only use upon approval by your veterinarian.
It is available as powders, tablets or in gel form and it should be given as directed by your veterinarian. VetRxDirect, 1-800-PetMeds, Vetsend.co.uk are some of the places you can find it.
It is slightly expensive, but it does not have any phosphorus. Its prices will depend on whether you are buying the gel, powder or tablet form.
This pork flavored sodium gluconate supplement comes in tablet, powder, or gel form. You can get it at VetRxDirect, Allivet.com, Drs Foster & Smith or Thriving Pets among other places.
It is a chewable brand which its manufacturer notes that most cats (over 60%) will eat it as a treat willingly. It is available on amazon.com, VetRxDirect, Medi-vet.com among other places.
Note: Due to the fact they are easier to mix with food, if you need potassium gluconate powder for cats, consider Renal K+, RenaKare, and Tumil-K. These same brands are also some of the best potassium gel for cats.
2.Potassium citrate for cats
This form is commonly used in renal diets. Settle for this brand if your cat suffers from metabolic acidosis . However, it is not recommended if your felines often suffer from urinary struvite crystals 
Since citrate is known to increase aluminum absorption, avoid using it together with phosphate binders that have aluminum or wait for at least two hours before giving it to your felines.
Common brands are the K-Cit-V (chewable tablets), Potassium Citrate+ Cranberry (chewable tablets and granules), Potassium Citrate Granules NutriVed, Urocit-K (extended-release tablets), CitraVet (chewable tablets), Nefrokrill (common in Europe or specifically Italy and it has phosphate binder (lanthanum carbonate and essential fatty acids).
3. Potassium chloride
It is cheaper but the oral form may worsen or contribute to metabolic acidosis. However, if you opt for the injectable version, brands like Slow-K will be ok.
Remember the Injectable potassium chloride 2 mEq/ml is also available but must be diluted by adding it to a fluid bag. Also, it stings a bit.
In case of renal diets
If your cat has renal failure and uses renal diets, as Conscious Cat notes besides “protein restriction, renal diets contain additional potassium, lower sodium, lower phosphorus and, in some cases, added Omega-3 fatty acids.”
Therefore, avoid extra supplementation of potassium, unless your vet allows you to do so to avoid incidences hyperkalemia.
Are there cat potassium supplement side effects?
Possible side effects of the oral brands include vomiting, stomach upsets, diarrhea, and poor appetites
Also, muscle weakness may be noted as well as interactions with diuretics, NSAIDs (such as Rimadyl), Difoxin, Glucocorticoids, Mineralocorticoids, ACE inhibitors including Benazepril, Penicillin as well as Corticotropin, notes PetMD.
For instance, an oral solid of potassium citrate or chloride may interact with Cyproheptadine meant to boost appetite if given at the same time causing stomach irritation.
In case of overdose or any of the hyperkalemia symptoms we already mentioned, contact your vet immediately.
Also, avoid buying any cat food with extra potassium unless your vet allows you to do so after determining there is a deficiency.