Which medications in the drug class Dopamine precursors are used in the treatment of Lewy Body Dementia?

Updated: Aug 08, 2019
  • Author: Howard A Crystal, MD; Chief Editor: Jasvinder Chawla, MD, MBA  more...
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Dopamine precursors

Patients with DLB have impaired dopaminergic tone due to disease in the substantia nigra and possibly other dopaminergic nuclei. The efficacy of the treatment of motor features in DLB depends on where the patient is on the Parkinson disease ̶ DLB spectrum. Whether or not levodopa influences cognition positively or negatively remains controversial, and its effect on cognition is probably modest.

Levodopa and carbidopa (Sinemet, Parcopa)

Levodopa is a large, neutral amino acid absorbed in the proximal small intestine by the saturable carrier-mediated transport system. Absorption is decreased by meals that include other large, neutral amino acids (although only patients with meaningful motor fluctuations need to consider a low-protein or protein-redistributed diet). The drug's half-life is approximately 2 hours.

Provide at least 70-100 mg/day of carbidopa; if more is required, substitute a 25/100 tablet for each 10/100 tablet. When more levodopa is required, substitute a 25/250 tablet for the 25/100 or 10/100 tablet. The controlled-release (CR) formulation is absorbed more slowly and provides more sustained levodopa levels than IR form does.

When it is initially required, the CR form is as effective as the IR form and may be more convenient. Patients with dissipating motor fluctuations and no dyskinesia often benefit from prolongation of the short-duration response when switched from the IR to the CR form. Patients with meaningful fluctuations and dyskinesia often have increased dyskinesia when switched to the CR form. Doses and intervals for the CR form may be increased or decreased to response.

Most patients are adequately treated with 2-8 tablets daily in doses divided every 4-8 hours when the patient is awake. Allow at least 3 days between dose adjustments. Levodopa/carbidopa may be administered as a whole or half tablet, which should not be crushed or chewed. Motor symptoms and signs may or may not improve.

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