The Use of Botulinum Toxin for Symptoms of Parkinson’s Disease, by Steven Markos, M.D.

There are various potential symptoms a patient may experience due to Parkinson’s disease. Some of these symptoms can be treated effectively with botulinum toxin injections. Cervical dystonia (abnormal neck muscle contractions), sialorrhea (drooling), and some forms of urinary dysfunction such as overactive bladder are FDA-approved uses for botulinum toxin. Botulinum toxin is also an off-label but common clinical treatment option for limb dystonia. To a much lesser extent, some tremors may benefit from treatment with botulinum toxin, though clinical evidence for this is currently lacking.

In general there are several notable potential benefits of botulinum toxin treatment. First, targeted injections to the area(s) of interest with botulinum toxin spares most if not all of the systemic side effects potentially posed by oral medications for the above conditions. In addition, botulinum toxin injections are often more potent and efficacious than oral medications. A single treatment can bring around 3 months of symptom improvement, and subsequent treatments are modifiable and individualized to each patient to optimize the therapeutic response.

Botulinum toxin works by reducing the signalling between a nerve and muscle, or in the case of sialorrhea between a nerve and salivary gland. The goal is to reduce the over-activity of the targeted muscle or gland. With skeletal muscles, when treating dystonia in the neck or limbs, we hope to tone down the abnormal, spontaneous contractions that can cause discomfort and malpositioning of a body part. With sialorrhea, we hope to decrease the excess amount of saliva produced by the salivary glands and decrease or eliminate drooling. With an overactive bladder, botulinum toxin injections (performed by a urologist) tone down the muscles of the bladder to reduce urinary incontinence. Botulinum toxin tends to take at least 3 days to start working, reaches peak effect around 4-6 weeks, and lasts around 3-4 months. At least 3 months must always pass in between subsequent injections. Injections can be repeated as long as there is clinical benefit demonstrated. Often, injections will be more beneficial to an individual when combined with other interventions, including physical therapy, occupational therapy, and a home exercise program that includes stretching.

In summary, botulinum toxin is a safe and effective treatment option to reduce the frequency and severity of several symptoms of Parkinson’s disease. If you experience symptoms of cervical dystonia, limb dystonia, sialorrhea, or overactive bladder due to Parkinson’s disease, consider asking your physician if treatment with botulinum toxin is an option for you.