Common Side Effects of Tolcapone
Tolcapone has been studied thoroughly in clinical trials. In these studies, the side effects that occurred in a group of people taking tolcapone (along with
carbidopa-levodopa) were documented and compared to the side effects that occurred in another group of people taking just
carbidopa-levodopa (without tolcapone). As a result, it was possible to see what side effects occurred, how often they appeared, and how they compared to the group taking just carbidopa-levodopa.
In these studies, the most common side effects of tolcapone plus carbidopa-levodopa included:
- Involuntary body movements (dyskinesia) -- in up to 51 percent of people
- Nausea -- up to 35 percent
- Sleeping problems -- up to 25 percent
- Loss of appetite -- up to 23 percent
- Uncontrollable, sustained muscle contractions (dystonia) -- up to 22 percent
- Excessive dreaming -- up to 21 percent.
Other common side effects (occurring in 1 to 20 percent of people) included:
- Muscle cramps
- Drowsiness or fatigue
- Diarrhea, constipation, abdominal pain (stomach pain), or vomiting
- Headaches
- The flu or upper respiratory tract infections, such as the common cold
- Increased sweating
- Dry mouth
- Urine discoloration
- Loss of balance
- Gas
- Increased muscle movements (hyperkinesia) or decreased muscle movements (hypokinesia)
- Chest pain
- Unusual sensations, such as burning, pricking, or tingling
- Arthritis, stiffness, or neck pain
- Bladder problems
- Sinus congestion
- Hyperactivity
- Hair loss
- Blood in the urine.
It is important to point out that many of these side effects are caused by carbidopa-levodopa, not tolcapone. However, this is of little importance because tolcapone is always used in combination with carbidopa-levodopa (it is not effective at treating
Parkinson's disease when used by itself). Also, because tolcapone increases the level of levodopa in the blood, it may increase the risk for or worsen the
side effects of carbidopa-levodopa.