Potassium

Potassium is an electrolyte that regulates muscle contractions, heart rhythm and nerve signals in dogs.

This mineral regulates fluid balance together with sodium. In a 25-kg dog, the normal potassium blood level is between 3.5 and 5.5 mmol/L. Deviations can become life-threatening.

Most quality foods contain sufficient potassium. It becomes problematic in cases of kidney disease, persistent diarrhoea or certain medications.

What symptoms does potassium deficiency show in dogs?

Potassium deficiency (hypokalaemia) manifests as muscle weakness and arrhythmias.

Your dog appears apathetic and has difficulty standing up. The hind legs give way because the muscles no longer work in a coordinated manner. In severe cases, arrhythmias occur, which you can feel as an irregular pulse on the thigh.

Triggers are usually chronic kidney disease or multi-day diarrhoea. Diuretics can also drive potassium levels down to zero.

How do you recognise a potassium excess?

Potassium excess (hyperkalaemia) leads to a slowed heartbeat and muscle weakness.

The heart beats noticeably slowly, under 60 beats per minute in a medium-sized dog. The weakness differs from deficiency: your dog moves stiffly, as if the muscles were cramped.

An excess arises almost exclusively in kidney failure or through overdosing of potassium supplements. It is practically impossible to achieve this through potassium-rich food alone.

Which foods contain a lot of potassium?

Bananas, sweet potatoes and pumpkin provide significant amounts of potassium for dogs.

A 2-cm banana slice (about 20g) contains 70mg of potassium. For a 15-kg dog, this corresponds to 0.3% of the daily requirement, which is negligible. 100g of cooked sweet potato provides 230mg, which is already more relevant.

Spinach is often recommended but contains oxalates. Better to opt for zucchini: 100g has 160mg of potassium without side effects.

These amounts are harmless for healthy dogs. With kidney problems, you must coordinate every potassium source with the vet.

When do dogs need potassium supplements?

Potassium supplements are only sensible in cases of diagnosed deficiency and under veterinary supervision.

The dosage is based on the blood level and body weight. Typical doses are 2-6 mmol per kg of body weight daily, divided into several administrations. Self-medication is dangerous; the line between deficiency and overdose is thin.

Potassium gluconate is better tolerated than potassium chloride. Always give tablets with food, as they can irritate the stomach lining.

The blood level must be checked after two weeks of treatment. Dogs with kidney disease often require lifelong potassium substitution.