OBJECTIVE: X-linked dystonia parkinsonism (XDP) is an adult-onset, progressive and debilitating movement disorder described among Filipino males from Panay Island. The available oral medications have been ineffective. While chemodenervation with botulinum toxin A works and deep brain stimulation surgery is promising, these are not affordable for the vast majority of patients. Thus, we decided to look into the efficacy, safety and tolerability of levodopa+carbidopa (levodopa) versus placebo among patients with XDP.

METHODS: This was a double blind, randomized, placebo-controlled clinical trial. Patients were randomized to receive levodopa or placebo for 6 months. The dose was increased gradually until 1000 mg levodopa/day is reached or until side effects appear.

RESULTS: A total of 86 out of 94 randomized patients (91.5%) were included in the intention-to-treat cohort for the primary efficacy analysis. Nineteen patients (9 in levodopa, 10 in placebo) dropped out or were lost to follow up. There was no significant difference in the baseline and last visit Burke Fahn Marsden Dystonia Rating Scale and the part III of the Unified Parkinson's Disease Rating Scale scores between levodopa and placebo. The most common adverse events in the levodopa group were increased movements, pain and nausea/ vomiting.

CONCLUSION: While levodopa is safe and well-tolerated, it does not have any effect in alleviating the dystonia or parkinsonism in XDP.