Paramedic National Registry Practice

What effect can administering more than 0.04 mg/kg of Atropine have on a patient?

1. Increased heart rate

2. Reflex bradycardia

3. Tachycardia

4. Hypertension

The correct answer is: Reflex bradycardia

Administering more than 0.04 mg/kg of Atropine can lead to reflex bradycardia due to the complex interplay of the drug's pharmacological effects and the body's response to its influence on the heart's autonomic regulation. Atropine is an anticholinergic medication commonly used to increase heart rate by blocking the vagus nerve's influence on the heart. However, in higher doses, especially beyond the recommended amount, there can be a situation where the body’s feedback mechanisms are activated. Reflex bradycardia occurs when an initial increase in heart rate leads to changes in blood pressure, which can stimulate baroreceptors. Instead of increasing heart rate further due to the anticholinergic effect, the body can respond by activating the parasympathetic system, resulting in a decrease in heart rate or bradycardia. This paradoxical response can be particularly notable in young patients or those with certain underlying conditions. In contrast, while increased heart rate and tachycardia can occur with standard doses of Atropine aimed at treating bradycardia, excessive doses may not produce these effects in a predictable manner. Hypertension can occur with sympathomimetic effects but is not directly associated with the