I have never used levodopa and I do not envy you trying to unravel all the side effects. Your description of a “chemically-induced anxiety/physical reaction” is a fair stab at a drug-induced condition called akathisia which has both mental and physical characteristics and is often misdiagnosed.
Since you describe your symptoms as being predictable it might be an idea to track what is happening with a diary so you can see the pattern in relation to drug timings & discuss with specialist.
Hopefully one day Parkinson’s UK will put up some official information pages about akathisia. The current Non-motor Symptoms Questionnaire does not use the word akathisia. It also comes under the umbrella term dyskinesia. It needs to be specifically differentiated from anxiety/restless leg etc. It also impacts on sleep & hugely on emotional well-being.
The wearing-off phenomenon and the use of questionnaires to facilitate its recognition in Parkinson’s disease Mark Stacy J Neural Transm (Vienna). 2010 Jul;117(7):837-46.
Early detection and management of wearing-off has been shown to improve patient symptoms; however, identification of wearing-off, particularly the non-motor symptoms, is hampered by a lack of patient education, awareness, patient-physician communication, and limited time for evaluation.
https://jnnp.bmj.com/content/jnnp/57/6/672.full.pdf
Parkinson’s disease C D Marsden J. of Neurology, Neurosurgery, and Psychiatry 1994;57:672-681
FLUCTUATIONS:…During off periods, many patients complain bitterly of pain and other sensory complaints, akathisia, respiratory distress, depressive mood swings, sweating and other autonomic symptoms, hallucinations, anxiety and panic attacks, sometimes with screaming, and slowing and impairment of thought processes.
Wearing-Off Scales in Parkinson’s Disease: Critique and Recommendations A.Antonini et al, Mov Disord. 2011 Oct;26(12):2169-75.
Wearing-off has been defined by some authors as a generally predictable recurrence of motor and nonmotor symptoms preceding scheduled doses of antiparkinsonian medication that usually improve postdosing. Although no formal consensus definition of wearing-off exists, the predictability of wearing-off differentiates it from ON– OFF phenomena, which are often unpredictable.
For some patients, wearing-off frequently also includes reappearance of nonmotor symptoms such as anxiety, fatigue, mood changes, difficulty in thinking, restlessness, sweating, or increased salivation.
Recent studies have reported that up to 50% of patients show the onset of motor fluctuations as early as 2 years after starting levodopa therapy or even within 5–6 months.
https://www.researchgate.net/publication/6888781_Development_of_a_Patient_Questionnaire_to_facilitate_recognition_of_motor_and_non-motor_wearing-off_in_Parkinson’s_disease
Development of a Patient Questionnaire to facilitate recognition of motor and non-motor wearing-off in Parkinson’s disease M. Stacy & R. Hauser Journal of Neural Transmission vol.114, (2007)
Lists 32 Wearing-off symptoms in Parkinson’s disease including: Panic attacks, Chest discomfort, Restlessness, Anxiety
https://www.rxlist.com/rytary-side-effects-drug-center.htm Rytary Side Effects Last reviewed on RxList 12/31/2019
The common adverse reactions leading to discontinuation during dose conversion were dyskinesia, anxiety, dizziness, and on and off phenomenon.
Rytary side effects include: A Feeling Of Restlessness With Inability To Sit Still, Anxious Feelings, Depression, Suicidal Behavior, Suicidal Thoughts, A Feeling Of General Discomfort Called Malaise, Nervousness
Carbidopa And Levodopa (Oral Route) Side Effects include: chest pain, trouble in breathing, Anxiety, restlessness
https://rxisk.org/akathisia/ Akathisia Author: RxISK Medical Team Last updated: 2018
Akathisia is an emotional state caused by over 100 different drugs…It can range from a constant and disturbing mental unease through to an intense emotional turmoil – and mental restlessness. This can be accompanied by physical discomfort, an inability to remain still, or an obvious motor restlessness or fidgetiness. The problems caused by treatment can in many cases be worse than the illness being treated….Sufferers often find it very difficult to explain exactly what is wrong, even though they may be in unbearable distress.
In milder cases, some people don’t realize how badly they are affected by the problem until they stop the drug or lower the dose…A common response from doctors when presented with symptoms of akathisia is to increase the dose, which then worsens the problem.
