How does insulin therapy influence potassium and acid-base balance?

• A. Insulin has no effect on potassium or acid-base balance.
• B. Insulin drives potassium into cells, lowering serum K+; reduces lipolysis and ketoacidosis, helping correct acidosis.
• C. Insulin raises potassium and worsens acidosis.
• D. Insulin causes metabolic alkalosis by shifting bicarbonate.

Answer: (B)

Insulin therapy shifts potassium into cells and reduces ketone production, which helps balance both potassium levels and acid-base status. Insulin stimulates the Na+/K+-ATPase pump, driving potassium from the blood into cells. That lowers serum potassium, a change clinicians must watch for, especially when starting treatment in patients with diabetic ketoacidosis or hyperglycemia, because total body potassium is often depleted even if the blood level looks normal or high. Clinically, this means potassium replacement may be needed as insulin therapy begins to prevent dangerous hypokalemia.

At the same time, insulin suppresses lipolysis and ketogenesis in the liver. With less free fatty acid release and fewer ketones being produced, the ketoacidosis component of the acid-base disturbance diminishes, leading to an improvement in metabolic acidosis as treatment progresses and glucose is corrected.

So the best answer reflects that insulin lowers serum potassium by driving potassium into cells and helps correct acidosis by reducing ketone production. It’s not accurate to say insulin has no effect on potassium or acid-base balance, to say it raises potassium or worsens acidosis, or to claim it causes metabolic alkalosis by shifting bicarbonate.