So when you call, don't start by asking to speak with the doctor. In a well-run office, the receptionists and nurses are trained to assemble the information needed for a preliminary evaluation of the situation. These people usually know which matters to handle alone and which ones the physician must handle personally. After talking to a receptionist or nurse, if you still believe it is necessary to speak with the physician, that is the time to ask. When you telephone, have a pad and pencil handy to write down any instructions.
Human memory is notoriously faulty.
Call as early in the workday as possible. The request should be made during the physician's office hours and before you are down to the last pill. That way the physician can review the office record to see whether the medication is still needed, whether the dosage should be changed, and so on. Such a review makes medical care safer. That is the safest way in the absence of medical records, but it does increase the cost of medication.