Levodopa

Levodopa is a precursor of the neurotransmitter dopamine and the most effective medication for the movement symptoms of Parkinson's disease, usually given with carbidopa.

Parkinson's disease involves loss of dopamine-producing neurons, and dopamine itself cannot cross from blood into the brain. Levodopa can, and once inside it is converted to dopamine. Carbidopa is combined with it to block conversion outside the brain, reducing nausea and allowing a smaller dose. After years of use many people develop fluctuations between periods of good control and periods when the drug wears off, along with involuntary movements called dyskinesia, which are managed by adjusting timing and formulation.

Levodopa is relevant in a cannabinoid glossary because cannabinoids have been studied in Parkinson's disease for tremor, sleep, pain and levodopa-induced dyskinesia, with small early trials and no established findings. CBD also inhibits liver enzymes involved in metabolizing many medications, so anyone taking levodopa or other Parkinson's drugs who is considering a cannabinoid product should discuss it with their neurologist or pharmacist. Nothing in current evidence supports replacing or altering Parkinson's medication with a cannabinoid product.