The root cause of Parkinson’s disease is the lack of dopamine, a neurotransmitter in the brain, so supplementing the brain with dopamine is the most basic treatment for Parkinson’s disease, but dopamine itself cannot be taken orally, nor can it work directly from the blood into the brain. It was later discovered that a substance called levodopa, which is structurally similar to dopamine and is a precursor of dopamine, could be taken orally and could be converted into dopamine by entering the brain from the bloodstream, thus providing a therapeutic effect. Then later, in order to reduce the breakdown of levodopa in the gastrointestinal tract and blood, upgrades were made, and so there were dopamine tablets (Medopa) and carzodopa controlled-release tablets (Benadryl), so what are the differences and similarities between these two drugs? Let’s look at them in detail.