Médicaments, maladie de Parkinson et syndromes parkinsoniens : actualités de pharmacovigilance

Drugs associated with restless legs syndrome: a case/noncase study in the French Pharmacovigilance Database

BACKGROUND

Several case reports have suggested that drugs could induce restless legs syndrome. However, no systematic review of this adverse drug reaction (ADR) in a pharmacovigilance database has been published.

OBJECTIVE

To assess the frequency of restless legs syndrome in the French Pharmacovigilance Database.

METHODS

We selected all ADR reports from January 1, 1984 to December 31, 2009 coded as restless legs syndrome. Restless legs syndrome diagnosis was validated from case descriptions. Using a case/noncase approach, reporting odds ratio and 95% confidence interval were calculated for "suspected'' drugs with 2 or more observations.

RESULTS

Twenty-six ADR reports were found. Four cases were excluded because of alternative diagnosis. Fourteen cases were women (64%). Median age was 57. Most frequently suspected drugs were antidepressants (reporting odds ratio, 15.9 [6.4-39.7]; amitriptyline, escitalopram, mianserine, mirtazapine, duloxetine), neuroleptics (17.8 [6.1-51.7]; thioridazine, loxapine, risperidone, aripiprazole) or tramadol (18.2 [6.3-52.8]).

CONCLUSIONS

Restless legs syndrome is a very rare ADR that was more frequently reported in association with antidepressants, neuroleptics, or tramadol.

Antiparkinsonian medication and pathological gambling

Parkinson's disease is a common condition, usually treated by dopaminergic agents, both ergot and non-ergot. Many behavioural abnormalities are associated with such usage, including impulse control disorders (ICDs), dopamine dysregulation syndrome and 'punding'. Pathological gambling, a form of ICD, comprises persistent and maladaptive gambling of various types that disrupts personal, family or occupational activity. Pathological gambling may be associated with other abnormal actions such as pathological shopping, hoarding and hypersexuality. The incidence varies widely from study to study but may be up to 7% of users of dopaminergic agents. Recognition of this problem has led drug regulatory agencies to add precautions concerning pathological gambling to official drug information for the entire class of antiparkinsonian medications. The literature is not entirely consistent and opinions differ greatly, but pramipexole (a dopamine D2 and D3 agonist), and perhaps ropinirole (also a D2/D3 agonist), may be especially likely to be associated with pathological gambling, although the precise nature of the relationship is unclear. Treatment involves reducing the dose of the medication or switching to another medication; unfortunately, the Parkinson's disease may worsen. The mechanism of this adverse effect is believed to be excessive dopaminergic stimulation but probably not specifically involving D3 receptors. A parallel to addictive behaviour with stimulant drugs has been noted.