Levodopa

Research summary

Scientific evidence from human studies, primarily using intravenous levodopa, demonstrates its safety and utility in over 2700 subjects, including healthy individuals, with no reports of death, psychosis, or serious adverse effects even at high doses. Outcomes measured include improvements in parkinsonian-like signs, alterations in sleep variables, hormone levels, hemodynamics, CSF amino acids, cognition, perception, and behavior, indicating broad dopaminergic influences. Research consensus supports levodopa's tolerability and value for investigating continuous versus pulsatile dopamine stimulation in humans, though applications are largely experimental rather than therapeutic for healthy populations. Studies in healthy controls confirm pharmacokinetic stability, with peripheral decarboxylase inhibitors enhancing bioavailability without altering distribution volume. While primarily established for Parkinson's disease, healthy human data reveal no neuronal toxicity and highlight potential for physiological research, though long-term oral use in healthy individuals lacks robust support.