What Are Off Episodes?
Parkinson’s disease is characterized by a lack of dopamine, a signaling molecule in the brain. One common approach to manage the tremors, stiffness, and slowness of Parkinson’s disease is to replace the missing dopamine with levodopa. Levodopa is a medication that is converted to dopamine within the brain. However, the effects of levodopa may begin to wear off early with long-term use.
The period of time during which levodopa controls the symptoms of Parkinson’s disease is called “on-time.” When the medication stops working, symptoms reappear and a so-called “off episode” starts. Off episodes may occur predictably, such as right before you are due to take your next dose, or they may happen suddenly and unexpectedly.
Initially, off episodes may be controlled by increasing the dose of levodopa or by increasing how often you take the medication. However, the dose cannot be increased too much because high doses of levodopa can lead to the development of dyskinesia, or uncontrolled and abnormal movements. Off episodes increase in frequency over time as Parkinson’s disease progresses. After 4 to 6 years of treatment, 40% of patients with Parkinson’s disease report off episodes, and nearly all patients experience them after 10 years. Patients may experience both motor and non-motor symptoms during an off episode.
Table: Common motor and non-motor symptoms during off episodes