Final answer:
By-the-clock (fixed-schedule) dosing in opioid therapy is characterized by fixed and administered dosages at scheduled intervals.
Step-by-step explanation:
A characteristic of by-the-clock (fixed-schedule) dosing in opioid therapy is dosage is fixed and administered at scheduled intervals. In this dosing strategy, the medication is given at specific times regardless of the patient's request or pain severity. This approach ensures consistent and regular administration of the opioid medication.