Study on drug-induced parkinsonism and its clinical patterns in Eastern Indian population

Background: Drug-induced parkinsonism (DIP) is important as it is reversible if identified and treated early. We present herewith various clinical patterns and drugs commonly causing DIP. Materials and Methods: This is a retrospective study with done at the outpatient neurology services of Aarogyam Neuroclinic, from Durgapur, West Bengal, during January 1, 2021–July 31, 2021. In this study, consecutive patients satisfying the inclusion criteria for DIP were included in the study. The inclusion criteria were: 1. All patients with two of the four cardinal features of parkinsonism – bradykinesia, tremor, rigidity, and postural imbalance. 2. There should be a temporal relationship of intake of medications before the onset of symptoms. 3. Exclusion of other causes of parkinsonism. The age, sex, and other demographic characteristics of study population were studied. The pattern of parkinsonism – symmetric, asymmetric, tremor-dominant, or rigidity-dominant was noted. Results: Out of 52 patients studied, 34 (65.38%) were male and 18 (34.61%) were female. The most common age group involved was 60–70 years (30.76%), followed by 70–80 years (26.92%) and 50–60 years (19.23%). The mean age was 60.61 years with a standard deviation of 13.44 years. On analysis of the clinical patterns of parkinsonism, the most common type was tremor-dominant symmetric parkinsonism (53.84%), followed by asymmetric parkinsonism (25%) and akinetic-rigid parkinsonism (21.12%). Orofacial dyskinesias were seen in 17.3% along with parkinsonism. Common drugs associated with DIP were gastrointestinal motility agent levosulpiride (25%), calcium channel blockers such as flunarizine (19.23%), aripiprazole (11.53%), amisulpiride (7.69%), sodium valproate (7.69%), olanzapine (3.8%), and itopride, flupenthixol, and risperidone (1.72%). Forty patients were followed up for 6 months, of which, majority (50%) showed complete recovery, whereas 25% each showed partial or persistent symptoms. Conclusion: DIP is a common disorder with varied presentations. Early diagnosis is crucial for complete recovery.