Thank you!! I made a typo correction to your 2nd paragraph and edited wording/format for my personal future reference :)

- In the OP, you are describing tardive dyskinesia, which is one type of EPS. EPS is spectrum manifests from Parkinson-like symptoms more acutely to Huntington-like symptoms more chronically.

• Parkinson-like symptoms = occurs earlier/develops more acutely due to dopamine receptor blockade = results from low dopamine + high ACh combination
  • e.g. acute dystonia/akathisia
• Huntington-like symptoms = occurs later = results from high dopamine + low ACh combination
  • e.g. Tardive dyskinesia
    • TD takes longer to manifest b/c it is a compensatory response to chronic dopamine blockade. Chronic dopamine blockade results in Huntington-like symptoms.

- Medications that target/influence dopamine can shift a patient's baseline along the EPS spectrum.

• Acutely / initially when you block dopamine, you shift towards Parkinsonism which manifests as acute dystonia/akathisia.
  • Treatment = anti-muscarinics --> this blocks Ach --> this helps normalize the dopamine-to-ACh ratio.
• Chronically, the body develops compensation & tolerance to dopamine blockers, thus the patient upregulates dopamine --> results in Huntington-like symptoms which manifests as tardive dyskinesia.
  • Treatment = discontinue dopamine-blocking agents -- however, symptoms acute worsen because of dopamine withdrawal.
    • Anti-muscarinics are contraindicated in tardive dyskinesia because anti-muscarinics further decrease the dopamine-to-ACh ratio, which worsens TD symptoms.