SYDNEY, AUSTRALIA – Nearly one-quarter of patients decreasing or stopping dopamine agonist therapy experience dopamine agonist withdrawal syndrome, and one third of those suffer severe symptoms, according to results from the EuroDaws study.
In the prospective, observational study of 51 patients with Parkinson’s disease who were withdrawn from dopamine agonist treatment, 24% (12 of 51) reported symptoms of dopamine agonist withdrawal syndrome (DAWS), and in 33% of those (4 of 12), the symptoms were classified as severe.
Miriam Parry
Previous retrospective studies had suggested a prevalence of 14%-18% for dopamine agonist withdrawal syndrome in clinical practice, however, study investigator Miriam Parry and her colleagues said this was the first prospective clinical study examining the frequency of the syndrome. Ms. Parry, a movement disorders nurse specialist from the University Hospital Lewisham, London, presented the study in a poster at the international congress of Parkinson’s Disease and Movement Disorders.
The researchers assessed patients regularly over a 1-month follow-up period, using a non–motor symptoms questionnaire.
The multicenter European study found the most common withdrawal symptom was anxiety, which presented in 91.7% of cases, followed by pain (50%), hyperhidrosis (41.7%), anhedonia (16.7%), apathy (8.3%), and limb paresthesia (8.3%).
"The third who developed the severe symptoms, patients become very anxious, they cannot perform their everyday activity of daily living, they won’t go out, they develop pain, sweating, apathy, and some become very, very depressed," Ms. Parry said in an interview.
The researchers suggested there was considerable potential for misdiagnosis of the withdrawal syndrome, which is similar to drug withdrawal for addictive drugs, and the symptoms could also be confused with non–motor fluctuations.
Ropinirole, pramipexole, and cabergoline were the three types of dopamine agonists implicated in the withdrawal syndrome, with patients being taken off these treatments because of the emergence of hallucinations or impulse control disorders.
"When we do decide to take them off the treatment, it has to be done in a very slow, gradual manner, and you really have to observe them," Ms. Parry said.
She said following the results, the researchers were also looking at ways to reduce the likelihood of withdrawal symptoms developing, such as slowly escalating the dose when patients are started on dopamine agonists but aiming for a much lower optimum dose of the drugs.
Ms. Parry said that while there were no particular red flags to indicate which patients were likely to develop the withdrawal syndrome, it did seem to occur in patients with preexisting tendencies to those symptoms, as if withdrawal was exacerbating those features.
"DAWS needs to be considered in day-to-day clinical practice and patients should be advised regarding this problem," the researchers wrote.
The study was supported by the U.K. National Institute for Health Research’s Mental Health Biomedical Research Centre and Dementia Biomedical Research Unit at South London and Maudsley NHS Foundation Trust and the Institute of Psychiatry, Kings College London. There were no financial conflicts of interest declared.