Table 4.

Treatment of Manifestations in Individuals with GTPCH1-Deficient DRD

ManifestationTreatmentConsiderations/Other
Dystonia/
parkinsonism 		Levodopa/DCI
  • Initial suggested dose 1, 2, 3 (a levodopa trial):
    • Children ˂6 yrs: 1-10 mg/kg levodopa/DCI daily, administered in multiple doses 3
    • Children ≥6 years: 25-50 mg levodopa/DCI 1-3x/day
    • Adults: 50 mg levodopa/DCI 1-3x/day
  • Changing the dose slowly & by small increments is recommended.
  • Motor benefit can be recognized immediately or w/in a few days of starting levodopa therapy; full benefit occurs w/in several days to a few months.
  • Maximum benefit (complete or near-complete responsiveness of symptoms) is generally achieved by <300-400 mg/day of levodopa/DCI.
Transient dyskinesias
assoc w/initiation
of treatment
w/levodopa/DCI 		Reduction of
dose of
levodopa/DCI
  • Transient dyskinesias do not reappear w/later gradual increment in dose.
    Note: Such transient dyskinesias are different from those observed in Parkinson disease during chronic levodopa therapy.
  • Typically, adverse motor effects of chronic levodopa therapy (motor response fluctuations and dopa-induced dyskinesias) do not occur.

From: GTP Cyclohydrolase 1-Deficient Dopa-Responsive Dystonia

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