A patient has been diagnosed with Parkinson disease and begins treatment with levodopa/carbidopa (Sinemet). After several months of therapy, the patient reports no change in symptoms. The nurse will expect the provider to:

A. Adding a dopamine agonist (e.g., pramipexole or ropinirole) is often used when levodopa therapy is effective but motor fluctuations develop. In this case, the patient has no response to levodopa, so adding a dopamine agonist would not be appropriate until the diagnosis is confirmed. B. The “on-off phenomenon” refers to fluctuations in motor control in patients who are already responding to levodopa, with periods of good mobility (“on”) and sudden immobility (“off”). Since the patient has no improvement at all, this phenomenon is not relevant yet. C. Increasing the dose of levodopa/carbidopa (Sinemet) is considered only after confirming the diagnosis and assessing for adequate therapeutic response. Blindly increasing the dose may increase adverse effects, such as dyskinesias, hypotension, or psychiatric symptoms. D. When a patient shows no clinical improvement after several months of appropriate levodopa therapy, the provider should re-evaluate the diagnosis. Parkinson’s disease can sometimes be misdiagnosed, and conditions such as atypical parkinsonism, essential tremor, or drug-induced parkinsonism may mimic symptoms but do not respond to levodopa.