Final answer:
Atropine should be administered to the client.
Step-by-step explanation:
The medication that the nurse should anticipate administering to a client receiving lorazepam IV for panic attacks and experiencing a response rate of 6/min and a blood pressure of 90/44 mm Hg is Atropine. Atropine is an anticholinergic medication that can help increase heart rate and blood pressure. In this case, the low blood pressure indicates hypotension, and the increased heart rate indicates bradycardia, both of which can be managed with atropine.