Aggression has been explicitly added to the patient information leaflet for ropinirole, a common medication used to treat restless legs syndrome and Parkinson's disease, following a European-wide safety review. Tens of thousands of individuals in Britain taking the drug could be at risk of developing aggressive outbursts, according to experts.
The medication, known by brand names Adartrel and Requip, is a dopamine agonist. It functions by mimicking the effects of dopamine, a hormone crucial for regulating movement and mood. Restless legs syndrome, characterized by an uncontrollable urge to move the limbs, affects approximately one in ten adults. The condition's symptoms are thought to be linked to disruptions in the brain's dopamine pathways. Ropinirole is also prescribed for Parkinson's disease, a condition marked by tremors due to diminished dopamine levels.
The behavioral side effects of dopamine agonists are believed to stem from their potential to overstimulate pleasure responses associated with dopamine, leading to impulsive actions. Previously documented behavioral changes linked to ropinirole have included pathological gambling, hypersexuality, and compulsive spending. Aggression was officially added to the drug's warning list on July 8th, alongside these other recognized effects.
Dr. Leyla Hannbeck, Chair of the Independent Pharmacies Association, stated that aggression has long been recognized by pharmacists as a rare but notable side effect of the drug. This update follows a 2025 BBC investigation where approximately 20 female patients accused doctors of failing to adequately warn them about serious side effects, which reportedly led to risky or sexual behaviors. Some women described developing uncontrollable urges to gamble or spend, resulting in significant debt, while others reported engaging in risky sexual behaviors.
One patient, who was prescribed ropinirole for restless legs syndrome that developed during pregnancy, experienced a significant improvement in symptoms initially. However, after a year, she began experiencing unprecedented sexual urges. She claimed she had not been warned about potential side effects, despite the UK's medicines regulator acknowledging that the drug could increase libido and lead to harmful behaviors. The patient reported that her impulses persisted to a point where she felt unable to control her actions, leading her to engage in dangerous situations. Her compulsive behaviors reportedly ceased almost immediately after discontinuing ropinirole.
Impulsive behaviors associated with ropinirole can include addictive gambling, excessive eating or spending, and an abnormally high sex drive or increase in sexual thoughts or feelings, alongside aggressive behaviors. The current patient information leaflet for ropinirole already references changes in sexual interest on five occasions.
Restless legs syndrome is estimated to affect about one in 20 adults, with women being twice as likely to experience it as men. Symptoms typically manifest as a strong need to move the legs, accompanied by uncomfortable sensations such as tingling, throbbing, or itching, and are often exacerbated at night. Treatment for the condition varies depending on the underlying cause, which can include pregnancy, iron deficiency, kidney disease, or certain medications.
Dopamine agonists like ropinirole are generally reserved for cases where other treatments, such as painkillers or anti-anxiety medications, have been ineffective. Robert Bradshaw, superintendent pharmacist at Oxford Online Pharmacy, noted that ropinirole has been a treatment option in the UK for over two decades, helping thousands of patients manage disruptive symptoms and remaining a valued part of standard care.
Patients currently taking ropinirole who observe any changes in their mood, behavior, or impulses are advised to consult with their general practitioner before discontinuing the medication. GSK, the manufacturer, has been approached for comment.