DEAR DR. ROACH: I’m a 65-year-old and otherwise healthy male. After spending the past five years believing that my trembling hands were the result of essential tremor, a second DaT (dopamine transporter) scan (the first one was misread, I guess) and a neurologist at a teaching institution confirmed that I am and have been suffering from Parkinson’s. The medicines that I have been prescribed are carbidopa / levodopa and recently amantadine.

While the meds are working well for now, what will the long-term issues with my liver and kidneys be after taking these medicines for the rest of my life — assuming, of course, that the dosage remains the status quo?

Also, what, if any, progress has been made with the effective treatment of this disease and the accompanying diagnosis of dementia with Lewy bodies? What does this mean anyway?

— D.V.

ANSWER: Parkinson’s disease is a common neurodegenerative disorder. Tremor is a common early sign as are slow movement and rigidity. A DaT scan is occasionally used to make the diagnosis of PD; however, it can be misinterpreted, so it should only be used by an expert when there is a clear reason. Separating essential tremor from Parkinson’s is a reasonable reason to get a DaT scan.

Both levodopa / carbidopa and amantadine are very frequently used for the treatment of PD. While nearly all medications can have adverse effects on the liver or kidneys, neither of these drugs is likely to cause significant damage, as long as the kidney and liver are monitored during therapy with blood tests.

Amantadine has recently been recognized to rarely cause swelling in the cornea, so new vision changes during treatment with this drug should prompt a visit with an ophthalmologist.

The effectiveness of levodopa / carbidopa tends to lessen over years, so there are other options that will be useful and that your neurologist has expertise with. As the course of disease is highly variable, I can’t tell you for sure what your course will be, but I’ve had many patients with PD who continue to do well for decades after diagnosis.

Dementia with PD is a significant issue. While they can be similar, PD dementia and dementia with Lewy bodies are not exactly the same thing. Lewy body dementia tends to come before or at the onset of the motor symptoms of Parkinson’s disease, while PD dementia usually happens years after a person has had symptoms. Lewy body dementia tends to have a faster clinical course than PD dementia.