Which medication should not be used in a pediatric patient for bradycardia if caused by increased vagal tone?

Adenosine is generally not indicated for treating bradycardia caused by increased vagal tone in pediatric patients. Instead, it is primarily used for the treatment of certain types of tachycardia, particularly supraventricular tachycardia (SVT), where it acts to slow conduction through the atrioventricular (AV) node. When bradycardia occurs as a result of increased vagal tone, the primary treatment involves using medications that increase heart rate, such as atropine, which counteracts vagal influence on the heart.

Using adenosine in a case of bradycardia from high vagal tone could potentially worsen the bradycardia or lead to undesirable effects because it may influence heart conduction in inappropriate ways when the heart is already beating slowly. Thus, it's important to select medications that support improved heart rate rather than those that might slow it further or affect conduction pathways utilized in bradycardia management stemming from vagal activity.