Why does the dosage of Selegiline hydrochloride tablets (Selegiline) need to be reduced when combined with levodopa?

Selegiline hydrochloride tablets (Selegiline) can enhance the efficacy of levodopa, but may exacerbate its side effects, such as involuntary movements, nausea, hallucinations, etc. When used in combination, the dose of levodopa needs to be reduced by approximately 30% to balance efficacy and safety. Clinical studies have shown that selegiline can prolong the action time of levodopa and reduce the "end-of-dose phenomenon", but blood pressure, heart rate and mental symptoms need to be closely monitored. If serious side effects occur, stop taking the medicine immediately and seek medical advice. It should be noted that the dosage of levodopa must be adjusted under the guidance of a doctor to avoid increasing or decreasing it on your own.