Welcome to HCM! I appreciate your concern for your father s illness. Parkinson s disease is characterized by muscle rigidity (stiffness), decreased movements, tremors due to deficiency of dopamine in the brain. The above mentioned medicines replenish the deficient dopamine stores in the brain resulting in decreased tremors, decreased stiffness and improved mobility. Syndopa is a combination of levodopa and carbidopa. The most common side effects seen with Syndopa are: Vomiting, anorexia, increased risk of GI bleeding in peptic ulcer patients. Orthostatic hypotension (can be fatal in elderly), cardiac arrhythmias. Other side effects seen on prolonged use include: Depression abnormal involuntary movements or dyskinesias, delirium, hallucinations (elderly). Rasalect can produce the following side effects:: loss of hair, loss of appetite, vomiting, diarrhea , constipation headache, dizziness, decreased libido. Since Parkinson s disease occurs due to deficiency or lack of dopamine, hence the treatment has to be life long but the dose reduction or adjustment can be done during the course of treatment. If you have additional queries, please don’t hesitate to ask. Best regards!