Final answer:
Antianxiety medications can increase concentrations of the cardiac drug NE (norepinephrine) by affecting the sympathetic system through the beta-1 receptors. Beta blockers, a type of cardiac medication, work by blocking these receptors and slowing down heart rate. Overprescription or improper use of these medications can lead to bradycardia or heart stoppage.
Step-by-step explanation:
The cardiac drug that can have its concentrations increased by antianxiety medications is NE (norepinephrine). Antianxiety medications, such as benzodiazepines and clonidine, work by affecting the central nervous system and can influence the sympathetic system. NE binds to the beta-1 receptor, and some cardiac medications like beta blockers block these receptors. By blocking the beta-1 receptors, these medications slow down heart rate and are commonly prescribed for hypertension. However, overprescription or inappropriate use of these drugs can potentially lead to bradycardia or the cessation of the heart's activity.