Drug safety monitoring in patients of movement disorders of a tertiary care hospital

Background : Movement disorders (MD) are neurological conditions that affect the speed, fluency, quality, and ease of movement and commonly include Parkinson′s disease, tremor and dystonias. Drugs are important causes of MD, and the incidence and prevalence of such disorders are possibly underappreciated because of the lack of recognition.
Objectives : To assess the incidence of all adverse drug reactions (ADRs) and estimate the prevalence of drug-induced MD among patients attending the clinic.
Materials and Methods : This prospective observational study was conducted at an outpatient referral MD clinic of a tertiary care hospital for 1 year. The demographic data, drug intake, diagnosis, and ADRs experienced by the subjects were recorded. Causality assessment was done by Naranjo′s scale.
Results : Incidence of ADR among patients who attended this clinic was 19.7% (151 out of 768 patients experienced at least one ADR). A total of 299 ADRs were detected out of which 30.8% were gastrointestinal, 28.4% psychiatric, and 26% MD effects. The commonly implicated suspect drugs were levodopa (37.8%) and trihexyphenidyl (25.1%). The prevalence of drug-induced MD was 10.15% and drug-induced dyskinesias and dystonias were the most common.
Conclusion : MDs are clinically important neurological disorders which are often caused by drugs and interestingly drugs used for its management are also associated with high incidence of ADRs. Hence these ADRs should be carefully monitored.

Keywords
Adverse drug reactions, drug-induced movement disorders, movement disorders, pharmacovigilance