You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
In this task, you will be given sentences in which your task is to recognize the name of the drug or medicine. Drugs are substances that change a person's mental or physical state. They can affect how your brain works, how you feel and behave, your understanding, and your senses. Although there might be several correct answers, you need to write one of them.

Acute pain was observed after taking MTX
Solution: MTX
Why? MTX is a medicine which has been mentioned here, and hence the name should be tagged.

New input: Optic neuropathy in ethambutol-treated renal tuberculosis.
Solution:
ethambutol