What serious adverse condition is a box warning associated with Hydrochlorothiazide and Triamterene?

The presence of a black box warning indicates that Hydrochlorothiazide and Triamterene, when used in combination, can lead to hyperkalemia, a condition characterized by abnormally high levels of potassium in the blood. This risk is particularly important to recognize because hyperkalemia can lead to serious complications, including cardiac abnormalities and arrhythmias.

Triamterene is a potassium-sparing diuretic that acts to inhibit sodium reabsorption in the distal nephron of the kidneys, which can lead to an increase in potassium levels. When combined with Hydrochlorothiazide, a thiazide diuretic that causes the loss of potassium, the two drugs can create an imbalance when not properly monitored, causing potassium levels to spike. The black box warning serves to alert healthcare providers and patients to the need for routine monitoring of potassium levels, especially in patients who may be at higher risk for electrolyte imbalances. This highlights the importance of understanding drug interactions and the mechanisms behind their effects on electrolyte balance.