A client with Parkinson disease is admitted to the hospital. Which medication is prescribed to improve the physical manifestations of Parkinson disease?

A client with Parkinson disease is admitted to the hospital. Which medication is prescribed to improve the physical manifestations of Parkinson disease?

• A. Pyridoxine (vitamin B6)
• B. Isocarboxazid
• C. Carbidopa-levodopa
• D. Dopamine

Answer: (C)

The key idea is dopamine replacement therapy for Parkinson disease and how to make it effective. Parkinson’s symptoms come from a shortage of dopamine in the brain, so giving a dopamine precursor that can enter the brain helps improve movement. Levodopa is that precursor, but if it’s given alone a lot is converted to dopamine outside the brain, causing nausea and other side effects and leaving less to reach the brain. Carbidopa blocks this peripheral conversion, so more levodopa reaches the brain and side effects lessen. This combination is what reliably improves motor symptoms. Pyridoxine (vitamin B6) would actually boost the peripheral conversion process and can reduce levodopa’s effectiveness, so it’s not the best choice to improve symptoms. Isocarboxazid is an MAOI that isn’t used to improve Parkinson’s motor symptoms and can cause dangerous interactions. Dopamine itself doesn’t cross the blood–brain barrier well, so giving dopamine directly won’t effectively treat brain dopamine deficiency. Therefore, carbidopa-levodopa is the appropriate prescription to improve physical manifestations.

The key idea is dopamine replacement therapy for Parkinson disease and how to make it effective. Parkinson’s symptoms come from a shortage of dopamine in the brain, so giving a dopamine precursor that can enter the brain helps improve movement. Levodopa is that precursor, but if it’s given alone a lot is converted to dopamine outside the brain, causing nausea and other side effects and leaving less to reach the brain. Carbidopa blocks this peripheral conversion, so more levodopa reaches the brain and side effects lessen. This combination is what reliably improves motor symptoms.

Pyridoxine (vitamin B6) would actually boost the peripheral conversion process and can reduce levodopa’s effectiveness, so it’s not the best choice to improve symptoms. Isocarboxazid is an MAOI that isn’t used to improve Parkinson’s motor symptoms and can cause dangerous interactions. Dopamine itself doesn’t cross the blood–brain barrier well, so giving dopamine directly won’t effectively treat brain dopamine deficiency. Therefore, carbidopa-levodopa is the appropriate prescription to improve physical manifestations.