21st June 2023

A 32-year-old man comes to the GP with difficulty walking and performing everyday tasks, like washing and dressing

A 32-year-old man comes to the GP with difficulty walking and performing everyday tasks, like washing and dressing.

On examination, the patient had a mask-like face, and was monotonous and slurred. He was extremely slow in carrying out all motor activities. He also had a normal neurological examination, except for bilateral resting tremor of the arms, and cogwheel and global muscular rigidity.

Considering the underlying diagnosis, which medication is the most likely cause of his presentation?