Reviewing tolcapone for patients with Parkinson’s disease

This study reviewed the effectiveness and safety of tolcapone (Tasmar) in treating patients with Parkinson’s disease (PD). Researchers suggested that tolcapone might be a good and safe option for the treatment of these patients.

PD affects the brain cells which control body functions. These cells lose their abilities leaving patients with symptoms such as tremors. The standard treatment is levodopa. However, long-term treatment with levodopa is associated with wearing-off symptoms. Wearing-OFF happens when the symptoms of PD come back before the next dose of levodopa, sometimes worse.

Tolcapone stops a protein from degrading levodopa. In the presence of tolcapone, levodopa is available in the bloodstream for longer. This results in a reduction of wearing-OFF symptoms. Prior studies showed the effectiveness of tolcapone in patients with PD. However, its safety is still not clear.

This study reviewed 32 other studies. These studies had information about 4780 patients with PD treated with tolcapone.

0.9% of the patients had increased liver enzymes in the blood. This indicates liver damage. Overall, 7 cases of severe liver disease associated with tolcapone were reported over 23 years. Of these, 3 cases led to death. All cases of death did not follow the guidelines for liver function follow-up.

In terms of effectiveness, the average decrease in hours per day spent in OFF was 2.1, at a levodopa dose of 108.9 mg. Most studies reported an improvement in the quality of life and PD symptoms.   

This study concluded that tolcapone improved wearing-OFF symptoms of patients with PD treated with levodopa, without major safety concerns.

The results in this study were not statistically analyzed. Also, there was no comparison between tolcapone and other similar drugs. Further studies are needed.