Relationship between polypharmacy and frequency of adverse events to antiparkinsonian drugs: a preliminary study.

Dr. María Verónica REYa, Dr. Santiago PEREZ LLORETa, Dr. Umberto SPAMPINATOb, Pr. Jean-Louis MONTASTRUCa, Pr. Olivier RASCOLc

a Faculté de Médecine, Université Paul-Sabatier, CHU de Toulouse, b Faculté de Médecine, Université Victor Segalen Bordeaux2, CHU de Bordeaux, c montastr@cict.fr

Objective: To evaluate the relationship between polypharmacy and most frequent AEs to antiparkinsonian drugs (APDs) reported by Parkinson disease patients.

Methods: 203 non-demented, non-operated Parkinson’s disease out-patients were recruited at the Toulouse and Bordeaux Movement Disorder Clinic (mean age 67 years, 62% males, and mean disease duration 9 years, mean UPDRS II+III in ON-state 37). They were systematically questioned about the presence of a predefined list of the most common AEs to APDs. Polypharmacy was arbitrarily defined as consumption of > 5 medicaments (i.e. the median in the sample). Medications were coded by ATC.

Results: Most frequent explored AEs were: weight loss, fatigue, leg oedemas, dry mouth, nausea/vomiting (NV), memory complaints, somnolence, impulse-control disorders (ICDs), orthostatic hypotension (OH), and psychotic events (PE). Polypharmacy was present in 68 patients (34%) and was related by multivariated logistic regression to weight loss (OR [95% CI]: 2.44 [1.07-5.56]), dry mouth (2.33 [1.25-4.37]), NV (2.72 [1.32-5.62]) and somnolence (1.87 [1.03-3.42]). On the other hand fatigue, oedemas, memory complaints, ICDs, OH and PE were not related to polypharmacy. Some medications were related to each of these AEs. Weight loss was independently related to H+-pump inhibitors (2.71 [1.00-7.45]) or domperidone (2.68 [1.12-6.41]); oedemas to dopamine agonists (2.42 [1.08-5.41]); dry mouth to amantadine (4.03[1.74-11.12]), opioids (OR could not be calculated) or antidepressants (3.16 [1.47-6.79]); memory complaints to statins (2.85 [1.09-7.45]); ICDs to dopamine agonists (OR could not be calculated) and MAO-B inhibitors (3.76 [1.12-12.67]); OH to lack of MAO-B inhibitors (0.08 [0.01-0.68]) and non-benzodiacepinic hypnotics (3.64 [1.46-9.04]); and PE to amantadine (3.03 [1.18-7.77]). Fatigue, NV and somnolence were not related to any particular drug.

Discussion: Polypharmacy was related to the occurrence of some AEs to APDs in this preliminary study including: weight loss, dry mouth, NV and somnolence. Moreover, the presence of several AEs was also related with particular drugs (leg oedemas, memory complaints, ICDs, OH and PE).

Keywords : polypharmacy - antiparkinsonian drugs - adverse events - Parkinson disease