Which of the following is a life-threatening side effect associated with diuretic therapy? a. Kidney stones. b. Cardiac arrhythmias. c. Peptic ulcers. d. Hypoxia.

The correct answer is b. Cardiac arrhythmias.<br /><br />Diuretic therapy, commonly used to treat conditions such as hypertension and heart failure, can lead to life-threatening side effects, including cardiac arrhythmias. Diuretics can cause an imbalance in electrolytes, particularly potassium, which is crucial for maintaining normal heart function. Low potassium levels (hypokalemia) can lead to dangerous arrhythmias, which are irregular heartbeats that can be life-threatening.<br /><br />While kidney stones (a) can be a side effect of certain diuretics, they are not typically life-threatening. Peptic ulcers (c) are more commonly associated with nonsteroidal anti-inflammatory drugs (NSAIDs) rather than diuretics. Hypoxia (d), or low oxygen levels, is not a direct side effect of diuretic therapy.<br /><br />Therefore, the most life-threatening side effect associated with diuretic therapy among the options provided is cardiac arrhythmias.