Dopamine Agonist–Induced Impulse Control Disorder in an Older Adult
Patient Background
Mrs. John is a 74-year-old female with a history of mild dementia, managed with donepezil 10 mg nightly. She resided in an assisted living facility and had been cognitively and behaviorally stable prior to the events described.
Clinical Presentation
Mrs. John developed severe nighttime restlessness, characterized by an irresistible urge to move her legs, resulting in frequent nocturnal awakenings and daytime fatigue. She was diagnosed with restless legs syndrome (RLS), and treatment was initiated with pramipexole 0.125 mg nightly, later titrated to 0.5 mg nightly due to persistent symptoms.
Over the ensuing months, her husband and caregiving staff observed marked behavioral changes. Mrs. John became uncharacteristically flirtatious, made sexually inappropriate comments, and displayed impulsive behaviors, including excessive fixation on romantic television programs. These behaviors were a significant departure from her baseline personality.
Clinical Issue Identified
Initial concern focused on progression of dementia. However, careful review of the medication timeline revealed that the onset of hypersexual and impulsive behaviors closely followed pramipexole initiation and dose escalation.
Dopamine agonists such as pramipexole are well known to stimulate mesolimbic dopaminergic pathways, which can precipitate impulse control disorders, including hypersexuality, compulsive gambling, binge eating, and compulsive shopping. Older adults and patients with cognitive impairment are particularly vulnerable.
Although there are rare reports of donepezil-associated behavioral disinhibition, the temporal relationship, dose dependence, and established risk profile of dopamine agonists strongly implicated pramipexole as the primary causative agent
Pharmacist Intervention and Clinical Management
Medication Review and Assessment
Identify pramipexole as the most likely cause of new-onset impulse control disorder.
Exclude delirium, infection, or acute neurologic deterioration.
Recognize that behavioral symptoms are not necessarily indicative of dementia progression.
Therapeutic Optimization
Gradually taper and discontinue pramipexole to minimize withdrawal symptoms and rebound RLS.
Avoid dose escalation or substitution with another dopamine agonist.
Alternative RLS Management
Initiate gabapentin, that binds α₂δ-1 subunit of Voltage-Gated Calcium Channels (VGCCs) as an alternative treatment for RLS.
Gabapentin offers symptomatic relief without dopaminergic stimulation and has a more favorable behavioral profile in older adults.
Monitoring and Follow-Up
Monitor for resolution of hypersexual behaviors and impulsivity over the following weeks.
Reassess sleep quality, daytime alertness, and RLS symptom control.
Continue routine cognitive monitoring while avoiding medications that increase neuropsychiatric risk.
Caregiver Education and Documentation
Educate family members and facility staff on recognizing drug-induced behavioral changes.
Document the adverse drug reaction clearly to prevent future re-exposure to dopamine agonists.
Clinical Rationale and Ramifications
This case illustrates the critical importance of considering medication-induced neuropsychiatric adverse effects when abrupt behavioral changes occur in older adults. Dopamine agonists are a well-established cause of impulse control disorders, and these effects may be misinterpreted as dementia progression, leading to unnecessary diagnostic escalation or inappropriate psychotropic prescribing.
In Mrs. John’s case, failure to recognize the drug-related cause could have resulted in persistent behavioral distress, social consequences within the care facility, and potential exposure to additional medications with significant risk profiles. Prompt identification and deprescribing of pramipexole led to complete resolution of symptoms, restoration of baseline personality, and improved sleep quality.
This case underscores the necessity of temporal medication review, cautious use of dopamine agonists in older adults, and preference for non-dopaminergic alternatives in patients with cognitive impairment. Recognizing adverse drug effects early can prevent harm, preserve dignity, and significantly improve quality of life.