Final answer:
The most common clinical use of narcotics today is for pain relief, often managed with opioids like morphine and codeine for various types of pain.
Step-by-step explanation:
The most common clinical use of narcotics today is for pain relief. Narcotics such as opioids, which include drugs like morphine and codeine, are frequently prescribed for both acute and chronic pain management. These substances act as depressants, often inducing effects such as sedation, anxiolysis, and importantly, significant analgesia. In the context of surgery, general anesthetics may be used to induce unconsciousness and block pain, with substances like halothane and ketamine being used. For non-surgical pain relief, lower doses of narcotics reduce pain without causing loss of consciousness, while higher doses can lead to drowsiness and unconsciousness.