ANTI-PARKINSON DRUGS

Brief History. M.M. is a 67-year-old woman who was diagnosed with Parkinson disease 6 years ago, at which time she was treated with a dopamine receptor agonist (ropinirole, 2 mg three times per day). After approximately 2 years, the bradykinesia and the rigidity associated with this disease began to be more pronounced, so she was started on a combination of levodopa-carbidopa. The initial levodopa dosage was 400 mg/d. She was successfully maintained on levodopa for the next 3 years, with minor adjustments in the dosage. During that time, M.M. had been living at home with her husband. During the past 12 months, her husband noted that her ability to get around seemed to be declining, so the levodopa dosage was progressively increased to 600 mg/d. The patient was also referred to physical therapy on an outpatient basis in an attempt to maintain mobility and activities of daily living (ADL). She began attending physical therapy three times per week, and the therapist initiated a regimen designed to maintain musculoskeletal fl exibility, posture, and balance.

Problem/Influence of Medication. The patient was seen by the therapist three mornings each week. After a few sessions, the therapist observed that there were certain days when the patient was able to actively and vigorously participate in the therapy program. On other days, she was essentially akinetic, and her active participation in exercise and gait activities was virtually impossible. There was no pattern to her good and bad days, and the benefi cial effects of the rehabilitation program seemed limited by the rather random effects of her medication. The patient stated that these akinetic episodes sometimes occurred even on nontherapy days.

1. What is the likely reason for the poor response to anti-Parkinson drugs on certain days?

2. What can be done to resolve this problem and improve the patient’s response to drug therapy?