Final answer:
The medication that will be ineffective and should be avoided in a 70-year-old male with a history of heart transplant experiencing symptomatic bradycardia is Atropine.
Step-by-step explanation:
In a 70-year-old male with a history of heart transplant experiencing symptomatic bradycardia, the medication that will be ineffective and should be avoided is b. Atropine.
Atropine is a medication that works by blocking acetylcholine receptors, which increases heart rate. However, in a patient with a heart transplant, the transplanted heart may not have these receptors, making atropine ineffective.
On the other hand, medications like a. Diazepam, c. Epinephrine, and d. Dopamine can be used to treat symptomatic bradycardia in this patient population.