Drug Induced Parkinsonism: An Overview

For more than half a century, drug induced Parkinsonism (DIP) has captured the attention of the physicians and researchers alike. More and more drugs underwent extensive scrutiny and causal agents were penned down from notorious antipsychotics [1] to more innocent anti-arrhythmic agents [2]. Earlier studies kept DIP as commonest cause of secondary Parkinsonism and the second commonest cause of parkinsonism second to idiopathic Parkinson’s disease [3-5]. A recent study showed not only reduction of 68.6% in the incidence of DIP over a 30-year period from 1976 to 2005 but also a relatively rare type of parkinsonism compared with other neurodegenerative types in persons aged 40 years or older [6]. This finding was attributed to substitution of typical antipsychotics by newer and safer atypical antipsychotics in psychiatric practice [6]. But due to reported safety profile, widely used atypical antipsychotics has been overlooked from suspicion of causing DIP [7]. Common drugs such as levosulpiride used in combination with proton pump inhibitors for dyspepsia causing DIP is on the rise [8]. Falling incidence can as well be true or it can be due to under recognition by the treating physician or over confidence in safety profile of certain agents. Although challenging, diagnosing DIP can help prevent unnecessary long term use of dopaminergic agents and its detrimental side effects.