Brief Answer: Your doctors may be right.... Detailed Answer: Hi, At the outset the beneficial effects and side effects that one gets from levodopa / carbidopa is from the amount of dopamine and the areas that it effects. Levodopa is supplemented with carbidopa to make sure the effects of dopamine stays predominantly on the central nervous system and NOT other organs. However if the dose is above tolerable limits it can make the individual sleepless, anxious, confused, psychotic and with dyskinesia. Systemic effects on heart leading to arrhythmias is possible if the dose of carbidopa is not enough. But again most preparation come with standard dosage in relation to levodopa. Therefore your doctors are mostly right. It is unlikely that carb/levo is causing the afib, dizziness and balancing issues. Let me know if you need clarifications. Regards

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