Propranolol Reduces Tremors in Parkinson Disease Patients

A recent study published in the Annals of Neurology has found that the beta-blocker propranolol can significantly reduce tremors in people with Parkinson’s disease, both during stressful situations and at rest. What Is Propranolol? Propranolol is a medication typically used to treat high blood pressure and heart rhythm problems. It’s also a common treatment for essential tremor, a condition that causes uncontrollable shaking. This new study explored whether propranolol could also help with the tremors caused by Parkinson’s disease. The Study at a Glance Researchers at Radboud University Medical Centre in the Netherlands conducted a double-blind, placebo-controlled study involving 27 participants with Parkinson’s disease who had prominent resting tremors. How It Worked: Participants were given a single 40-mg dose of propranolol or a placebo on two separate days. Researchers then measured: Tremor severity using accelerometry (a tool to track movements). Brain activity related to tremors using functional MRI (fMRI). Heart rate and pupil size to assess stress levels. Stress Test: To simulate stress, participants were asked to perform mental arithmetic tasks, which increased their heart rate and pupil size (indicating a stress response). What Did They Find? Propranolol was effective in reducing tremors both during stress and while at rest: During Stress: Tremors typically worsened when participants were stressed, but propranolol reduced their severity compared to the placebo. At Rest: Surprisingly, propranolol also lessened tremors even when participants were not under stress. Brain scans showed that propranolol decreased tremor-related activity in the motor cortex, the brain region responsible for movement. Why Does It Work? Tremors in Parkinson’s disease are caused by abnormalities in the dopamine system. However, the study found that the stress hormone noradrenaline plays a role too. Stress Amplifies Tremors: According to Dr. Rick Helmich, one of the study’s authors, noradrenaline acts like an “amplifier” in the brain’s movement areas, intensifying tremors. Propranolol blocks this effect, helping to reduce the shaking. Resting Tremors and Stress Hormones: The team was surprised to discover that the stress hormone system can be active even when a person is at rest, causing spontaneous fluctuations in tremors. What Does This Mean for People with Parkinson’s? Propranolol could offer a valuable new option for treating tremors in Parkinson’s, especially for those whose symptoms don’t fully respond to standard dopaminergic medications. “This medication may provide relief for patients struggling with tremors that worsen under stress or persist during rest,” said lead author Dr. Anouk van der Heide. Looking Ahead While these findings are promising, propranolol isn’t a one-size-fits-all solution. Its effects on heart rate and blood pressure may limit its use for some people. Still, this research opens the door to better understanding how stress affects Parkinson’s symptoms and how to manage them. For those living with Parkinson’s, propranolol might soon become a helpful addition to their treatment plans, offering more control over one of the disease’s most challenging symptoms.