**Question:** Which of the following opioid has local anaesthetic properties?

A. Codeine
B. Morphine
C. Fentanyl
D. Hydromorphone

**Core Concept:**
Opioids are a class of drugs that act on the central nervous system to produce analgesia (pain relief) and other effects such as sedation, respiratory depression, and gastrointestinal effects. Local anaesthetics, on the other hand, are drugs that produce reversible inhibition of neural conduction by blocking voltage-gated sodium channels in neurons.

**Why the Correct Answer is Right:**
The correct answer, B. Morphine, is a potent opioid with strong analgesic and sedative properties. Morphine does not have local anaesthetic properties.

**Why Each Wrong Option is Incorrect:**
A. Codeine: Codeine is also an opioid with analgesic properties but lacks significant local anaesthetic activity.
C. Fentanyl: Fentanyl is a potent opioid analgesic but lacks significant local anaesthetic properties.
D. Hydromorphone: Hydromorphone is an opioid analgesic with minimal local anaesthetic activity.

**Clinical Pearl:**

While some opioids are used in clinical practice for their analgesic properties, local anaesthetic properties are not a common feature of this drug class. Understanding these differences can help in choosing appropriate medications for specific clinical scenarios.

In summary, the correct answer, Morphine, is an opioid analgesic with limited local anaesthetic properties, while the other options are also opioids but lack significant local anaesthetic activity. This distinction is important for selecting the most suitable medication for pain management based on the required properties.