Certified Medical-Surgical Registered Nurse Practice Exam

What symptom of hypoglycemia could be masked by the administration of metoprolol tartrate (Lopressor)?

1. Diaphoresis.

2. Tingling.

3. Diplopia.

4. Tachycardia.

The correct answer is: Tachycardia.

The correct choice is tachycardia, which can be masked by the administration of metoprolol tartrate. Metoprolol is a beta-blocker that primarily affects the cardiovascular system, by reducing heart rate and contractility. In cases of hypoglycemia, one of the body’s primary responses is to increase heart rate (tachycardia) as part of the fight-or-flight response. However, when a beta-blocker like metoprolol is given, this response is blunted, making it difficult to recognize tachycardia as a symptom of low blood sugar. When considering other symptoms of hypoglycemia, diaphoresis (excessive sweating) is usually not affected by beta-blockers. Tingling and diplopia (double vision) are also not primarily related to adrenergic responses and tend to remain apparent even when beta-blockers are administered. Therefore, the masking effect of metoprolol is specifically relevant to tachycardia in the context of hypoglycemia.