BB and electrolyte imbalance

Q: Beta blockers may cause? (select one)

A) Hyperkalemia

B) Hypernatremia

Answer: A

Rarely discussed on clinical grounds is the possible hyperkalemia from beta-blockers, mostly from the nonselective beta blockers such as propranolol and labetalol. Beta-2-adrenergic activity are involved in driving potassium into the cells. Beta blockers interfere with this beta-2-adrenergic facilitation of potassium uptake by the cells. This is particularly after a patient receives a potassium load. Although clinically this may not be apparent but rise can be up to 0.5 mEq/L, particularly in patients who are on angiotensin-converting enzyme(ACE) inhibitors, and angiotensin receptor blockers (ARBs).

This BB-K connection is important in ICU where labetalol is frequently use after kidney transplants, and may cause life-threatening hyperkalemia. (see reference #1)

#pharmacology

#electrolytes

References:

1. Arthur S, Greenberg A. Hyperkalemia associated with intravenous labetalol therapy for acute hypertension in renal transplant recipients. Clin Nephrol 1990; 33:269.

2. Lim M, Linton RA, Wolff CB, Band DM. Propranolol, exercise, and arterial plasma potassium. Lancet 1981; 2:591.