A purely synthetic opioid is

Options

A. Codeine
B. Heroin
C. Morphine
D. Pethidine

Answer

To solve the question "A purely synthetic opioid is", let's analyze the options provided: codeine, heroin, morphine, and pathidine.

### Step-by-Step Solution:

1. **Understanding Opioids**:
- Opioids are drugs that are derived from opium, which is the dry latex of the poppy plant (Papaver somniferum). They are known for their narcotic effects, meaning they can suppress brain function and relieve pain.

2. **Types of Opioids**:
- Opioids can be classified into two categories:
- **Natural Opioids**: These are directly derived from the opium plant. Examples include morphine and codeine.
- **Semi-Synthetic Opioids**: These are derived from natural opioids but undergo chemical modifications. An example is heroin, which is made from morphine.
- **Synthetic Opioids**: These are entirely manufactured through chemical processes and are not derived from the opium plant. An example of a purely synthetic opioid is pathidine.

3. **Evaluating the Options**:
- **Codeine**: This is a natural opioid derived from opium.
- **Heroin**: This is a semi-synthetic opioid derived from morphine.
- **Morphine**: This is also a natural opioid derived from opium.
- **Pathidine**: This is a purely synthetic opioid, created through chemical processes and not derived from opium.

4. **Conclusion**:
- Based on the definitions and classifications, the correct answer to the question "A purely synthetic opioid is" is **pathidine**.

### Final Answer:
**Pathidine** is the purely synthetic opioid.