3 Clinical psychopharmacology3.3 Pharmacodynamics

3.3.6.5 Dopamine agonists

Creator: Resident Doctor Committee
Published: 2026-10-14T21:05:16.259Z

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Written by Resident Doctor Committee · Published 14 October 2026

Drugs

Dopamine agonists act mainly at D2-family receptors and cause more hallucinations, sleepiness and impulse control disorders than levodopa.

Agent	Type	Notes
Pramipexole, ropinirole	Non-ergot, D2 and D3	Impulse control risk; pramipexole is renally cleared
Rotigotine	Non-ergot patch	Delivers drug over 24 hours
Bromocriptine, cabergoline	Ergot-derived	Fibrosis and valve risk; treat hyperprolactinaemia
Apomorphine	Subcutaneous	Treats "off" periods; causes nausea

Impulse control disorders

Dopaminergic drugs used for Parkinson's disease and restless legs can cause impulse control disorders by acting on mesolimbic reward pathways, which are rich in D3 receptors.

Sagittal diagram of the brain showing dopamine pathways leaving the midbrain: the mesolimbic pathway (green) from the ventral tegmental area to the nucleus accumbens, the mesocortical pathway (orange) to the prefrontal cortex, and the nigrostriatal pathway (red) from the substantia nigra to the dorsal striatum. — Follow the green mesolimbic pathway from the ventral tegmental area to the nucleus accumbens: this reward route, rich in D3 receptors, is where dopaminergic drugs act to cause impulse control disorders, separate from the red nigrostriatal pathway that serves movement. Oscar Arias-Carrión, Maria Stamelou, Eric Murillo-Rodríguez, Manuel Menéndez-González and Ernst Pöppel, substantially modified, CC BY 2.0, via Wikimedia Commons

Common forms are pathological gambling, compulsive buying, hypersexuality and binge eating.
Punding is prolonged repetitive activity.
Dopamine dysregulation syndrome is compulsive overuse of dopaminergic medication.
Risk rises with total dopaminergic exposure, younger onset and a history of addiction, yet it can appear at low doses or without a dose change.
Patients often hide these behaviours out of pleasure, shame or poor insight, so ask specifically before treatment and at each review.

Other adverse effects

Hallucinations often start as a sensed presence or movement at the edge of vision before becoming formed people or animals.
Sudden sleep episodes come without warning, and patients affected should stop driving and seek licensing advice.

Psychosis

Agonists given for antipsychotic-induced hyperprolactinaemia can worsen psychosis, so review the antipsychotic with specialists instead.
In Parkinson's psychosis, NICE supports selected low-dose quetiapine or clozapine, with required monitoring.

Revision material for the MRCPsych examinations. Not clinical guidance, and not for use in patient care.