The beta blocker propranolol can help reduce tremors linked to Parkinson’s disease when the standard treatment for the neurodegenerative pathology, levodopa, no longer succeeds.
- The standard Parkinson’s medication, levodopa, does not always work against the tremors caused by the disease, especially during times of stress.
- A study finds that the beta blocker propranolol helps fight Parkinson’s tremors, even in stressful situations.
- Researchers suggest that the stress hormone norepinephrine acts as an amplifier in patients, and that propranolol manages to block this phenomenon.
When patients with Parkinson’s disease face stressful situations, their tremors increase and the standard treatment, levodopa, often becomes ineffective.
Researchers at Radboud University Medical Center seem to have found a solution: propranolol. This beta-blocker, used for years against high blood pressure, cardiac arrhythmias as well as tremors without a neurological cause, manages to reduce the problems of patients, even when they are stressed.
Their work was published in the journal Annals of NeurologyDecember 21, 2024.
Parkinson’s: propranolol reduces tremors, even in stressful situations
To determine whether propranolol could be useful for patients affected by Parkinson’s disease, the team brought together 27 people who suffered from the neurodegenerative pathology. The volunteers took propranolol one day then a placebo the next. Tremors were measured by a device placed on their hand and an MRI measured their brain activity. These examinations were performed both at rest and during a task involving stressful mathematical calculations. Stress response was assessed by participants’ pupil size and heart rate.
“As expected, without medication, the tremors worsened during stress”specify the scientists in their press release. Most importantly, the data showed that propranolol reduced patients’ tremors at rest and during the stress episode.
Tremors: the role of stress highlighted
The MRIs allowed researchers to understand how this treatment acts on tremors as well as the effect of stress. Once the drug was taken, the brain circuit responsible for the tremors showed less activity. “We know that abnormalities in systems like the dopamine system cause tremors. Based on our study, we now believe that the stress hormone norepinephrine acts as an amplifier. This increases the intensity of tremors in the area of brain movement. Propranolol inhibits this amplifying effect and thus reduces symptoms.explains neurologist Rick Helmich of Radboud University Medical Center.
The scientist and his team also noticed that propranolol also reduces tremors at rest. “Apparently our stress system is sometimes active, even at rest.”notes researcher Anouk van der Heide. “We previously thought that the stress hormone system was only active under stress, but apparently that’s too simplistic. It also plays a role at rest.”
Thus the study confirms that propranolol can be a solution for patients in whom levodopa is not effective. However, Dr Helmich calls for caution when prescribing it, due to its side effects such as low blood pressure.
