Carbidopa-Levodopa – A Combinational Dopaminergic Antiparkinson’s Nootropic


Carbidopa is yet another dopaminergic drug that is recommended in the treatment of people with Parkinson’s symptoms. However, its efficacy is very low therefore it has to be combined with levodopa for it to work effectively. This combination is known as carbidopa-levodopa. It is the combination that is now prescribed to combat Parkinsonism. Parkinson, as we all know, is as a result of low concentration of dopamine in certain parts of the brain. The carbidopa is also used to suppress some of the side effects caused by levodopa such as nausea and vomiting.

Levodopa is normally taken orally, and it crosses the blood brain barrier (the BBB) into the brain. Once inside the brain, the L-dopa is converted into dopamine. The subsequent increase in brain dopamine concentration as a result of the conversion of L-DOPA leads to improved nerve conduction as well as aiding in the arresting of movement disorders in people suffering from Parkinson’s disease.

carbidopa-levodopaThe purpose of carbidopa is to prevent the premature breaking down of L-DOPA before it reaches the brain. It does not cross the brain itself. Its addition allows lower doses of levodopa to be used. This phenomenon reduces the risks of suffering from levodopa’s side effects. This happens because carbidopa helps more L-DOPA into the brain while less of the same stays in the bloodstream. A doctor can, therefore, increase more of the levodopa in order to find the right dose for you.

How to use Carbidopa-levidopa

This combination comes as a daily tablet that disintegrates orally. It is a long-acting (extended-release) tablet taken by mouth. The tablets either regular or orally disintegrating ones are generally taken three or four times per day. The long acting one is typically taken two to four times per day. Carbidopa and levodopa should be taken at around the same times per day.

The study of L-DOPA as a potential dopaminergic drug started in the year 1960 by Oleh Hornykiewicz, the Austrian biochemist. However, work on this potentiality continued until 1971 when Lotti showed that the use of the L-form of carbidopa reduced the therapeutic dose of levodopa in the range of 1-2 grams per day. The drug was then patented under the name Sinemet.

One of the significant reservations against carbidopa-levodopa combination is that it may be harmful to pregnant and nursing women. Much as there are no human studies that have shown its adverse effect on the fetus, similar studies on animals have shown those ramifications. Moreover, it is distributed in milk that may inhibit its production. Therefore, a physician should carefully consider the potential risks the drug may have if a patient is either pregnant or is breastfeeding.


  1. It treats Parkinsonism
  2. Carbidopa reduces levodopa’s side effects
  3. It may have other essential applications in medicine


  1. It is expensive
  2. You need a prescription to get one
  3. It is harmful to a certain category of patients
  4. It interacts with other drugs
  5. It has side-effects in the body

Before using carbidopa-levodopa drug, make sure that you have instructions from a physician.

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