Final answer:
The pharmacist needs to review each resident's drug regimen quarterly to ensure the medications are appropriate and safe.
Step-by-step explanation:
The pharmacist needs to review each resident's drug regimen quarterly.
This regular review is important to ensure that the medications prescribed to the residents are still appropriate, effective, and safe.
By reviewing the drug regimen every three months, the pharmacist can identify any potential drug interactions or changes in the resident's health that may require adjustments to the medications.