Can Seroxat (paroxetine) cause Parkinson´s disease?/nA 73-year-old man has been treated with paroxe

Fråga: Can Seroxat (paroxetine) cause Parkinson´s disease? A 73-year-old man has been treated with paroxetine 20 mg daily since 1993 due to a psychiatric disorder. The last month he has developed tremor in his left hand, arm and leg.

Sammanfattning: We have not found any documentation supporting that selective serotonin reuptake inhibitors may cause Parkinson´s disease. However, parkinsonism has been reported for several selective serotonin reuptake inhibitors. The symptoms usually occur within the first month of treatment and generally resolve within a few days to one month after reducing the dose or stopping the treatment.

Svar: Extrapyramidal reactions (EPRs) including acute dystonic reactions, parkinsonism, neuroleptic malignant syndrome, akathisia, and dyskinesias have been reported for several selective serotonin reuptake inhibitors (SSRIs) alone or in combination with neuroleptics (1,2). Possible mechanisms by which SSRIs cause EPRs include 1) central serotonergic activity which inhibits dopaminergic activity 2) concurrent use of an SSRI and antipsychotic may cause EPRs by a pharmacokinetic interaction, a pharmacodynamic interaction, or a combination of the two (1). In many case reports near maximum recommended dose or maximum doses were used (1). The majority of reactions occurred within the first month of treatment. EPRs generally resolve within a few days to one month after reducing the dose or withdraw the SSRI (1,2).

In SWEDIS (3) there are five reports of parkinsonism, 16 reports of tremor, and six reports of dyskinesia on paroxetine treatment.

Parkinson´s disease is mainly a disorder of middle or late life (4). Although symmetric in the later stages, the disorder typically begins asymmetrically, eg, as a slight tremor of the fingers of one hand or in one leg. The tremor is generally most pronounced in the hands (4). The prevalence of depression in patients with Parkinson is high, 40 per cent (range 25-70 per cent). Moreover, depression may develop before the motor symptoms appear in Parkinson´s disease (5).

In the present case it is not possible to distinguish whether this is the first sign of Parkinson´s disease or some other neurological disease with extrapyramidal symptoms or a drug-induced reaction. The late onset of symptoms in relation to treatment duration speaks against paroxetine as the causing agent. One way to elucidate if the symptoms are caused by paroxetine is to decrease the dose or withdraw paroxetine since the symptoms generally resolve within days to one month after such measures. If that is not the case it suggests that the patients symptoms may be caused by some neurological disease.