Final answer:
The nurse should tell the spouse of a client taking tacrine for Alzheimer's disease to monitor the client's weight, notify the healthcare provider about changes in stool color, and inform them that darker urine is normal while on the medication.
Step-by-step explanation:
The nurse should tell the spouse of a client taking tacrine for the management of moderate dementia associated with Alzheimer's disease to monitor the client's weight regularly, as weight gain may be a possible side effect of the medication. It is also important to notify the primary health care provider if there is a change in the color of the stools, as this could indicate a liver problem. While on tacrine therapy, it is normal for the urine to have a darker color.