Final answer:
When administering local anesthetics to a patient taking Elavil, a tricyclic antidepressant, levonordefrin should be avoided due to potential serious cardiovascular side effects such as increased blood pressure and arrhythmias.
Step-by-step explanation:
The patient is taking Elavil, a tricyclic antidepressant, and the question is what should be avoided when administering a local anesthetic. The correct answer is b. Avoid levonordefrin. Levonordefrin is a vasoconstrictor that is sometimes combined with local anesthetics to prolong their action. However, tricyclic antidepressants may increase the effects of directly and indirectly acting sympathomimetic agents, such as levonordefrin, leading to increased blood pressure and possible arrhythmias. Therefore, it's recommended to avoid using local anesthetics with levonordefrin in patients taking tricyclic antidepressants like Elavil. It's important to consult with the patient's physician or a pharmacist if there is any uncertainty about drug interactions.
Topical anesthetics (a) can still be useful for surface anesthesia without significant systemic interactions. Local anesthetics (c) in general are not contraindicated, and amides (d) refer to a class of local anesthetics that do not interact adversely with tricyclic antidepressants.