Publication:

Adverse drug reaction to antiparkinson agents in Idiopathic Parkinson Disease: a prospective observational study in a Movement Disorder outpatient clinic

Background Parkinson disease (PD) generally requires therapy for prolonged periods often with multiple drugs; drug-related adverse effects often add to the existing morbidity. Although, such ADRs are common, comprehensive information about their incidence, severity, and ultimate health effects are not available. The objective of the study was to analyze the pattern of occurrence of Adverse Drug Reactions (ADRs) in patients receiving anti-parkinson agents (APA) in a tertiary care hospital. We also aimed to assess the causality, severity and preventability of these ADRs.

Methods This prospective, observational study with 6 month follow up was conducted among consecutive PD patients receiving anti parkinson agents attending the Movement disorder clinic of Neurology department between April 1st 2011 and September 30th 2012. Tools used were ADR Reporting form of National Pharmacovigilance centre, WHO causality scale, Hartwig and Siegel scale to assess severity and Schumock and Thornton scale to assess preventability of ADRs. Descriptive statistics was used and the values were expressed in numbers and percentages.

Results ADRs were experienced in 87 patients (82.1%) out of 106 patients and most of these patients were on combination therapy (66%). No gender difference in distribution of ADRs was observed. The most common reactions were sedation, dizziness, dry mouth and fatigue. The drug usage was in the order of pramipexole (58.4%), levodopa+carbidopa (55.7%), trihexyphenidyl (28.3%), entacapone (5.7%) and amantadine (7.5%). Majority of the ADRs were mild level 1 (71.1%). ADR was maximum with entacapone. Majority of ADRs belonged to the causality possible ADR category. All the ADRs came under the definitely or probably preventable category.

Conclusions ADRs with antiparkinsonian drugs is common but mild and preventable.