A 72-year-old patient came to a doctor with complaints of hand tremors, stiffness, slowness of walking and speech, and difficulties in performing routine household chores. Physical examination detects general bradykinesia, hypomimia, emprosthotonus," shuffling" gait, hand tremors at rest, D > S, plastic type of increased muscle tone, the" cogwheel rigidity" phenomenon, and marked postural instability. What medicines must be a primary part of the treatment regimen for this patient?