If a hospital pharmacy is not open 24 hours a day what options do they have for filling medications "after hours"?

The hospital pharmacy provide medicine for the patients admitted in the hospital. The pharmacy cannot be open for the 24 hours a day so the hospital must provide some alternate facilities.

The filing medications can be done by allowing the limit access for the medication by the specific personnel nursing. The pharmacist can be on call as well. The off site pharmacy outside the hospital must be present and can deliver the medications.