if a person is charted half to 1 of an "x"tablet once a day and you give the person half but its not effective within a few hours. can you still give the other half or is it a drug error if you do? another example if morphine 2.5 to 5 mls is prescribed every 4 hours and you give 2.5. after 1 hour the patient is still in pain can u still give another 2.5. to chase the 5mls.?