Parkinsons Disease Home > Comtan Side Effects
In clinical studies, involuntary body movements, diarrhea, and nausea were the most common side effects reported with carbidopa-levodopa and Comtan. Side effects are usually minor and do not require medical attention, but some can become quite significant and intolerable over time. Some of these potentially serious side effects of Comtan include severe muscle pain, psychiatric problems, and high or low blood pressure.
As with any medicine, side effects are possible with Comtan® (entacapone). If side effects do occur, they are often minor and either require no treatment or can easily be treated by you or your healthcare provider. However, as with any levodopa therapy, many people will begin to experience significant and sometimes intolerable Comtan side effects over time.
(This article covers many, but not all, of the possible side effects with Comtan. Your healthcare provider can discuss a more complete list of Comtan side effects with you.)
Comtan has been studied thoroughly in clinical trials. In these studies, the side effects that occurred in a group of people taking Comtan (along with carbidopa-levodopa) were documented and compared to side effects that occurred in another group of people taking just carbidopa-levodopa (without Comtan). This way, 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 Comtan plus carbidopa-levodopa included:
- Involuntary body movements (dyskinesia) -- in up to 25 percent of people
- Nausea -- up to 14 percent
- Diarrhea -- up to 10 percent
- Urine discoloration -- up to 10 percent
- Excessive muscle movements (hyperkinesia) -- up to 10 percent
- Slow or diminished muscle movements (hypokinesia) -- up to 9 percent
- Dizziness -- up to 8 percent
- Abdominal pain (stomach pain) -- up to 8 percent.
Other common side effects (occurring in 1 to 6 percent of people) included:
- Increased sweating
- Back pain
- Taste changes
- Dry mouth
- Indigestion or heartburn
- Red or purple bruise-like spots (known as purpura)
- Bacterial infection.
It is important to point out that many of these side effects are caused, in large part, by carbidopa-levodopa, not by Comtan. However, this is of little importance, since Comtan is always used in combination with carbidopa-levodopa (the drug has no activity against Parkinson's disease when used by itself). Also, because Comtan increases the level of levodopa in the blood, it may increase the risk of or worsen side effects of carbidopa-levodopa.